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Land subsidence is a worldwide geological hazard. Differential land subsidence has posed the major threat to urban infrastructure, linear rail transit and underground space development and utilization, and also restricted the sustainable development of the economy and society. This paper systematically elaborates on the research progresses on land deformation acquisition, evolution mechanism and simulation of land subsidence, and focuses on the land deformation acquisition technology based on InSAR monitoring and multi-source deformation data fusion, as well as the correlation analysis, statistical analysis, machine learning and other methods to analyze the relationship between the evolution of land subsidence and various influencing factors based on geotechnical experiment and long time series observation data. On this basis, the advantages and disadvantages of land subsidence simulation models such as groundwater flow field-land deformation model, mathematical statistical model and machine learning model are explored. It is found that multi-source deformation data fusion can improve the spatiotemporal resolution of land deformation. The differences in geological structure, lithology, groundwater exploitation, and dynamic and static loads are factors contributing to the differential evolution of land subsidence. The difficulty in balancing the computational efficiency and interpretability of mathematical models for land subsidence is the main problem in simulation. According to the literature review, the current researches mainly focus on land subsidence caused by groundwater over-exploitation. This paper further proposes the future research directions for land subsidence, under the background of climate change, new hydrological condition and dataset, and based on the fusion of data through remote sensing and field observations, integrating the latest progress of InSAR, GeoAI, cloud platform and other technologies to reveal the evolution mechanism of land subsidence considering the climate change and anthropic activities and provide technical support for regional land subsidence prevention and urban safety.

Landslide disasters occur frequently in Fujian Province, and early warning of landslide disasters on a regional scale is an important means of effective disaster prevention and mitigation. Due to the complex mechanism of landslide disasters, the traditional regional landslide early warning methods have such problems as insufficient accuracy. Deep learning mainly refers to the technology of feature extraction, abstraction, representation and learning by constructing the neural network model, which is a kind of machine learning. As a classical deep learning algorithm, convolutional neural network has more powerful classification and representation ability than traditional machine learning. Taking Fujian Province as the research area, this paper introduces the convolution neural network into the field of landslide disaster early warning and constructs a regional landslide early warning model of Fujian Province. The process is as follows: (1) The SMOTE optimization algorithm is used to optimize the sample database of landslide disasters in Fujian Province from 2010 to 2018, enlarging the number of positive samples and expanding the proportion of positive and negative samples from 1∶3.4 to 1∶2, and the total number of samples reaches 18040. (2) Construct a convolution neural network model structure, which includes an input layer, two convolution layers, two maximum pooling layers, a full connection layer and an output layer. (3) Use the convolution neural network to train the optimized samples (80% of the samples from 2010 to 2018 as the training set), and use the Bayesian optimization algorithm to optimize the model parameters to obtain the regional landslide early warning model of Fujian Province. (4) The model is tested with 20% of the samples from 2010 to 2018 as the test set, and the confusion matrix and ROC curve are used to test the model. The results show that the accuracy of the model ranges from 0.96 to 0.97, the AUC value is 0.977, indicating that the model accuracy and generalization ability are good. (5) The actual situation of the landslide disaster in the flood season of 2019 is taken as a positive sample, negative samples are collected through the method of time-space sampling, and the 2019 regional landslide sample verification set (603 samples) is constructed. The model is further verified by using the confusion matrix and ROC curve. The results show that the accuracy of the model ranges from 0.75 to 0.85, and the AUC value is 0.852. Although only the actual landslide samples in the flood season of 2019 is used for verification, good results is also achieved. In this paper, the convolution neural network algorithm is applied to the regional landslide early warning, which provides a new way to establish the regional landslide early warning model. The preliminary verification shows that the model is effective and will be further applied and verified in Fujian Province in the future.

Kaolin is a common clay in engineering. The microstructure of kaolin is very sensitive to the change of pore environment. At present, the research on the relationship between pore environment characteristics and acoustic wave velocity of kaolin remains to be further studied. In this paper, based on the ultrasonic test theory, RSM-SY6 ultrasonic detector is used to study the change rule of ultrasonic wave velocity of kaolin under different pore environment conditions. In addition, the influence mechanism of pore environment characteristics on ultrasonic wave velocity of kaolin is analyzed from the microscopic perspective of the arrangement mode of clay particles and the interaction between clay particles and pore solution. The results show that (1) the ultrasonic wave velocity of kaolin decreases with the increasing void ratio. (2) With the increasing water content, the ultrasonic wave velocity of kaolin decreases slightly at first and then increases greatly. (3) The effect of pore solution pH value on ultrasonic wave velocity of kaolin is related to the edge isoelectric pH value. When the pore solution pH value is equal to the edge isoelectric pH value, the ultrasonic wave velocity is the maximum. (4) The addition of salt reduces the ultrasonic wave velocity of kaolin. When the concentration of saline solution ranges from 0 to 0.5 mol/L, the wave velocity decreases rapidly. Under the same anion condition, the high valence cation has a more obvious effect on the reduction of ultrasonic wave velocity. This paper provides a reference for the study of the acoustic characteristics of viscous soil, and also provides a theoretical basis for the application of ultrasonic detection technology in soil.

Remarkable achievements have been made in groundwater management in China since the implementation of the strictest water resources management system. Groundwater has been restored to some extent. By the end of 2020, the shallow groundwater level generally showed an upward trend in the Northeast China Plain, the Huang Huai Hai Plain and the Middle and Lower Yangtze Plain, and the decline rate of deep groundwater level was slowed down. Only 291 monitoring stations have an average annual decrease in groundwater level of over 2 m, accounting for 8.7% of the total national monitoring stations. However, there are still many problems difficult to solve, mainly reflecting in some areas where the groundwater level continues to decline, the balance between mining and replenishment has not yet been reached, and land subsidence still occurs. Meanwhile the effectiveness of over-exploitation area management has not been as significant as expected. In this paper, we first briefly review the progress and obtain achievements of strict groundwater management and groundwater over-exploitation area treatment in our country. Then we discuss the main problems faced by groundwater management in China, e. g., unclear delineation of hydrogeological conditions, inadequate accuracy of groundwater monitoring and measurement, inconsistency between groundwater management objectives and current technics, immature external conditions for groundwater management, and difficulty in groundwater ownership registration. The targeted countermeasures are put forward, mainly including strengthen the study of groundwater circulation and transformation from the perspective of watershed or regional water balance, strengthen the research and pilot of groundwater double-control indicator determination method, further strengthen the groundwater monitoring and mining output measurement and statistics, and further clarify the responsibilities of groundwater management. The determination method of groundwater dual-control management index is demonstrated. It is proposed that the quantitative relationship between groundwater exploitation and groundwater level should be clarified, based on the resources, geological environment, and ecological environment functions of groundwater level to determine water level control indicators, and the reasonable dual-control index should be determined considering the actual demand, groundwater management objectives, precipitation years and other conditions. This paper deeply think about the probable problems of strict groundwater management and groundwater over-exploitation treatment in China, and the solving ways of the problems is also proposed. It can provide a basis for sustainable utilization and scientific management of groundwater in China

On 26 June 2023, a catastrophic debris flow occurred in the Banzi Catchment in Wenchuan county of Sichuan province. This debris flow event is a viscous debris flow triggered by short duration heavy rainfall. The volume of debris which transported out of the catchment by debris flow is more than 8.3×105 m3, and the debris flow blocked the Minjiang River. The river blockage formed a barrier lake with an area of about 0.4 km2. To reveal the formation mechanism of the occurrence of the extremely large debris flow events 15 years after the Wenchuan earthquake, This paper adopts a comprehensive method of field investigation, image interpretation, topographic superposition and calculation of forced vortex. This paper also analyzes the formation mechanism of debris flow and the characteristics of river blocking. Based on the results, this paper gives some suggestions of investigation and prevention of debris flow in the Banzi catchment. The research results show that (1) the triggering rainfall is characterized by short duration and high intensity. The main initiation positions are in the channel. The main debris supply is from the debris deposition along the channel. (2) The peak discharge of debris flow is as high as 755.5 m3/s, which is the main cause of river blockage. (3) Since the Wenchuan earthquake, the debris flow activity of the Banzi Catchment has the characteristics of lag and long-term because of the coupled transport of debris on the slope and along the channel. (4) The volume of the debris source which can be eroded along the channel should be paid more attention in subsequent investigation and prevention. The research results are helpful in better understanding of the activity evolution of the post-seismic debris flow. They can also provide scientific references for the prevention of the post-seismic debris flow..

At present, the creep problem of underground engineering surrounding rock still exists, and the creep theory needs to be further enriched. In essence, rock creep is a process of constant accumulation of damage. In view of the damage evolution of rock under creep conditions, triaxial creep tests are carried out on red sandstone taken from Yibo Tunnel in Leshan, Sichuan Province by TAW-2000 to analyze the creep deformation rule of specimens under different confining pressures. Based on Weibull distribution and Perzyna viscoplastic theory, an improved viscoelastoplastic creep model is established which can describe the whole process of rock creep failure. The critical point damage variable is defined by dividing the creep stage, so that the acceleration creep start time can be determined more accurately. The following conclusions are drawn: (1) the model curve in this paper is in good agreement with the test data, which verifies the accuracy and rationality of the model in this paper, and indicates that the viscoelastic-plastic creep model of red sandstone established based on Weibull distribution is feasible. (2) Based on Perzyna viscoplastic theory, a more accurate viscoplastic strain expression is established to describe accelerated creep. (3) The triaxial damage creep model established in this paper based on Weibull distribution and Perzyna viscoplastic theory can describe the whole process of rock creep well, overcoming the shortcoming of the Siyuan model which can not describe accelerated creep. The relationship between rock creep deformation and damage can be better reflected by defining the critical point damage variables of different creep stages, which enriches the creep constitutive theory of rock materials.

Prediction of water inflow of a sub-sea tunnel under the blasting vibration effect is still a difficult subject. This paper takes the sub-sea tunnel between the Wawuzhuang Station and Guizhou Road Station of the Qingdao Metro Line 1 as the engineering background. Based on the equivalent continuum model, the mirror image method is used to deduce the calculation formula for the water inflow of the sub-sea tunnel considering the damage area factor. Through forward modeling and inversion, combined with numerical simulation results and actual engineering monitoring results, the correctness of the formula is comprehensively verified, and the influence mechanism of damage area factors on water inflow is analyzed. The results show that the squeezing effect caused by blasting vibration makes the pore water pressure of surrounding rock around the tunnel rise rapidly in a short time. After reaching the peak value, it began to decline slowly with the weakening and disappearance of blasting vibration. Under the influence of damage zone factors, the water inflow of the tunnel increases gradually with the increasing thickness of the damage zone, but it will not increase continuously with the increase of the coefficient of permeability in the damaged area. Through numerical simulation calculation, the ratio of tunnel water inflow considering blasting damage area is 1.4, and the error is only 4.1% compared with the calculation result of 1.342 deduced in this paper. The calculated results in this study are only 0.53 m3/(d·m) less than the field measured results, and are closer to the measured results than those with the traditional calculation formula, indicating that the calculation formula in this paper is suitable for the calculation of tunnel water inflow considering the factor of damage zone, and are of high engineering application value.

A great mountain seismic often triggers a large number of co-seismic landslides, causing direct damage to local vegetation cover and growth. As an important indicator of landslide activity intensity, the vegetation recovery is of great significance for the activity of post-earthquake geo-hazards. However, due to the limitation of observational data, the current research on vegetation restoration process in earthquake areas is mostly on a small scale. In addition, there is insufficient understanding of the vegetation evolution mechanism in a large area and the relationship between vegetation and the activity of geological disasters. Therefore, this paper uses multi-temporal and long-time series (2000−2020) high-precision remote sensing images to study the vegetation restoration process in the Wenchuan earthquake area. By calculating vegetation recovery rates in different periods, we explore the universal law of vegetation restoration in a large range, and analyze the relationship between vegetation restoration and the change of landslide activity intensity. The results show that by 2020, 71.34% of the landslide area in the earthquake area has been better restored. The proportions of highly active, moderately active, low active and basically stable landslides are 17.6%, 12.4%, 17.7% and 52.3%, respectively. The surface recovery trend of co-seismic landslide indicates that the vegetation in the Wenchuan earthquake area is expected to recover to the pre-earthquake average level about 17 years after the earthquake. However, the process of vegetation recovery and changes in landslide activity are often subject to the combined effects of multiple factors. Although the vegetation recovery of landslide surface reflects the decline of landslide activity after the earthquake to some extent, the effects of the earthquake on landslide activity will last longer than the recovery of surface vegetation to the pre-earthquake level. Referring to the results of previous studies, this paper suggests that the post-earthquake landslide activity will last 25 years or more.The conclusion can provide reference for the assessment and prevention of post earthquake geological disasters in Wenchuan earthquake area.

The heat exchange between geothermal wells and surrounding formations is important to the heat production of geothermal wells. Due to the difficulty in arranging measurement points around geothermal wells in real engineering, it is hard to verify the results of geothermal reservoir modelling, thereby verify the modelling results. Therefore, geothermal wells are only considered as source/sink in most of the previous geothermal reservoir modeling, and the coupled flow and heat transfer between the geothermal fluid and the reservoir is not considered. In contrast, lab-scale experiments are convenient to arrange the measurement points, and the experimental results can verify the coupled geothermal reservoir-wellbore numerical model. However, how to achieve the lab-scale formations with geotemperature gradients is the key issue, and there are no similar studies yet. In this paper, based on the basic principles of heat transfer, a lab-scale simulated formation with high geotemperature gradient is quickly achieved. By determining the geometric size of the simulated geothermal reservoir and caprock, selecting the filled porous media and a simulated reservoir with constant temperature, a simulated formation with high geotemperature gradient is designed. Through the layered heating and boundary dynamic thermal supplementation method, the linear temperature distribution of the simulated formation at the reservoir temperature of 60 °C, 65 °C and 70 °C, respectively, are achieved. The relative error between the numerical simulation obtained by the finite volume method and the experimental results is within the range of ±2.5%, indicating that the simulated and experimental results are in good agreement, which can provide experimental conditions for the coupled reservoir - wellbore heat transfer experiment. The simulated formation system designed and established in this paper can provide experimental conditions for the reservoir-wellbore heat transfer experiment, and then verify the developing numerical software of coupling the reservoir-wellbore flow and heat transfer.

The soil layer in the canal first section of the Middle Route of the South-to-North Water Transfer Project (MR-SNWTP) is mainly composed of expansive soil, and changes in water content of the expansive soil affect the stability of the slope. In order to make a reasonable assessment of the stability of expansive soil canal slopes, it is necessary to test and analyze the relevant physical and mechanical properties of the expansive soil on canal slopes at different water content. In this paper, titration-direct shear tests are carried out on the expansive soil collected from the canal first section of MR-SNWTP to obtain the relationship between the shear strength parameters and water content of the expansive soil. The test results show that the shear strength decreases significantly with increasing water content, and the decay process starts fast and then slows down. The lower the initial water content of the sample is, the slower the cohesion decreases, and the faster the angle of the internal friction decreases, and the shear strengths of the sample with different initial water content all show an inflection point when the water content increases to about 30%, when the decay rate decreases and becomes stable. Hydraulic conductivity tests based on soil-water characteristic curve method and instantaneous profile method are designed to obtain the hydraulic conductivity-water content curve of unsaturated expansive soil. The test results show that the lower the water content is, the smaller the hydraulic conductivity is and the faster the change rate of hydraulic conductivity is. Conversely, the slower the change rate of hydraulic conductivity is, and the more stable the soil water content tends to be. The research results of this paper can be used for quantitative analysis of the relationship between the stability of the expansive soil canal slopes and the groundwater level of the slopes. In practical applications, they can also be used to effectively obtain the distribution characteristics of water content and shear strength in the unsaturated soil of the canal slope, and to obtain the time variation laws of water content and shear strength, and a more accurate stability evaluation model is established based on spatial dynamic shear strength analysis of the expansive soil of the canal slopes.

Israel is located in the Middle East. Due to it’s geographical position and low-amount and uneven-distributed precipitation, Israel is short of natural fresh water resources. National government has developed innovative technologies in producing, transporting and recycling water resources to solve its water shortage crisis. After several-year efforts, Israel has changed from a country with water scarcity to an agricultural country with highly-effective use of water resources. Israel is even called as the ‘Vegetable Basket for European countries’. This paper firstly introduces Israel’s geography and climate condition, as well as it’s water type, then introduces the utilization structure of water resources, and finally introduces six scientific and technological innovations used to prevent water crisis. This paper aims to share experience of effective use and management of water resources and to provide references for international cooperation and academic study.

Since 2002, the China Geological Survey has successively organized and implemented hydrogeological survey and groundwater exploration in water deficient areas, such as severe water shortage areas in west China, Wumeng Mountain area, Yimeng mountain area and red bed area in southern Jiangxi, obtained a large number of exploration data conducive to promoting discipline development, and summarized the law of water abundance. In recent decades, water prospecting and well drilling in bedrock mountainous areas serving poverty alleviation have not been systematically summarized based on water storage structures and their attributes. This paper takes the water storage structure as the theoretical guidance, considers geomorphic catchment, lithological water accumulation, structural water control and other control factors, and takes structure as the main control factor. The factors such as topography, formation lithology, vegetation development and actual value of development and utilization are systematically summarized and water storage structures are divided into 8 types, further divided into 20 types, and more into 35 types, such as the horizontal rock stratum, monocline formation, fold, fault, contact zone, weathered crust, composite and cave reservoir. The common characteristics of different scales and types of water storage structures are analyzed and summarized with reference to and in combination with the neotectonic water control theory and groundwater system theory. From the aspects of spatial combination characteristics of water storage structure, boundary hydrogeological properties, hydrodynamic conditions, scale effect, symbiotic characteristics of water control and practical value of development and utilization, this paper puts forward the correlation between the lithology and geological structure, the relativity of permeability and water separation, the balance between catchment and water storage, the unity of scale and system, the inheritance of formation and transformation and the matching of scale and purpose. The research results refine and improve the classification of groundwater storage structure types in bedrock mountain areas with water shortage, summarize the attribute characteristics of water storage structure, deepen the understanding of the concept and connotation of water storage structure, not only further promote the research of hydrogeology in bedrock mountain areas, but also provide references for water prospecting and well locating in water shortage areas, and guide the sustainable utilization of water resources in water shortage areas.

The traditional field contact measurement for obtaining parameters of the rock mass discontinuity is of low efficiency and big workload, and the accuracy of the results are affected by human factors. In this paper a method is presented to automatically recognize the discontinuity based on the three dimensional (3D) digital surface model (DSM) of rock mass obtained with the digital photogrammetry and structure from motion (SFM) algorithm. The steps of rock mass DSM reconstruction include collecting rock mass images, matching image features based on the Scale-Invariant Feature Transform (SIFT) algorithm, reconstructing sparse point cloud, encrypting point cloud, and reconstructing the rock mass surface model. The main flow of the discontinuity recognition method include smoothing the DSM of rock mass, changing the searching radius and the angle threshold to split model plane, searching the discontinuity based on the regional growth principle, and fitting the discontinuity based on random sampling consistency to get the orientation. The method is applied to the underground experimental roadway in the Beishan area of Gansu, and the reconstruction of 3D digital surface model of roadway and the orientation acquisition of discontinuities are realized. The discontinuities are also mapped on the roadway model by groups. A comparison the results with those of the manual field measurement method and the existing discontinuity recognition software shows that the method proposed in this paper is of good accuracy and can provide a certain reference for engineering applications.

Identifying the permeability structure of the dam foundation rock mass is important for the formulation of seepage control schemes. For the horizontally-stratified red-bed rock mass of the Yellow River Guxian Dam foundation, this paper adopted a "continuous, high-resolution" water pressure test data processing method to analyze the relationships between rock mass permeability and elevation, lithology and shear zones, clarifiy the permeability structure of the dam foundation rock mass, and propose seepage control advice. The results indicate that the Guxian Dam foundation rock mass is characterized by a structural and random permeability behavior. The structure shows that the permeability decreases with elevation. The randomness shows that the permeability randomly fluctuates due to lithology and shear zones. For the river-bed dam foundation rock mass, the bottom elevation of the weathering and unloading zone is 450 m or so, and the 1Lu bottom boundary is at the elevation of approximately 340 m. For the rock mass of the dam abutment, the 3Lu bottom boundary is located at the elevation of 560～580 m. The section of 350～360 m elevation has a certain thickness of soft rock, a poor development of shear structure, and a low permeability. It can be regarded as a confining layer and a potential target for the optimization of seepage control schemes. In view of the universal applicability, the method proposed in this paper can be used for reference in similar projects.

The abandoned mines along the Yangtze River in Jiangsu Province is the key area along the Yangtze River Economic Belt, which need to be restored and governed. Among the ecological restoration projects, it has been one of the difficulties that how to quickly and intuitively track the progress of the distribution and restoration of a great many abandoned mines in the region. In this paper, the author takes the 10 km area on both sides of the Belt as study object. And selects high-resolution remote sensing images in each year from 2017 to 2020 as the data source. By human-computer interactive interpretation on the ArcGIS platform and field verification, the author obtains the information such as the distribution of open-pit abandoned mines, geological environment problems and ecological restoration in the study area. This paper mainly focus on the geological environment problems existing in abandoned mines and summarizes the ecological restoration measures. It is shown that it ’s a wide area need to be restored in Zhenjiang and Nanjing. The area of open-pit abandoned mines mainly focus on the quarries and transit sites of the mines, with construction limestone and construction sand mines as the main types of mines involved. The environmental problems mainly include topography and geomorphological destruction, geological disasters, ecological environment damage and soil and water pollution, etc. And the part rehabilitated and being rehabilitated of the study area show an increasing trend from 2018 to 2020. As of October 2020, the restoration area of abandoned mines has been effective, with 67.08% of the area restored. The main ecological restoration measures include natural restoration, soil backfilling, land leveling, slope cutting and integrated land management. It is recommended that the original landform of the mining area should be protected to the maximum extent and the land resources fully utilized when carrying out restoration and treatment. The results and suggestions provide technical reference for the ecological restoration and treatment of open-pit abandoned mines in the same type of area.

Biological reinforcement is a new branch that has developed in the field of engineering geology in recent years, among which, the microbially induced calcium carbonate precipitation (MICP) reinforcement technology is an effective method. MICP reinforcement technology utilizes the metabolic activity of widely existing microorganisms in nature to induce the precipitation of calcium carbonate with cementing and filling effects, thereby improving the strength of soil, reducing its permeability, and enhancing its engineering performance. Over the past two decades, significant progress has been made in theoretical research, model experiments, and field trials of MICP reinforcement technology. To promote a deeper understanding of MICP reinforcement technology, this paper systematically introduced the reinforcement mechanism and influencing factors of microbial-induced calcium carbonate reinforcement technology based on the current research on MICP reinforcement technology. In addition, the application of MICP reinforcement technology was discussed thoroughly. The current problems and challenges of MICP technology were analyzed in depth. The results show that the strengthening mechanism of MICP is formed based on microbial-induced mineralization, which includes the filling and cementation of soil pores by calcium carbonate precipitation. The influencing factors of the solidification effect of MICP mainly are the properties of bacterial solution and cementing solution, pH , temperature, soil type, and reinforcement method, by influencing the formation of calcium carbonate and cementing effect. The MICP reinforcement technology has shown great potential in soil reinforcement, crack resistance, impermeability, wind erosion resistance, and remediation of contaminated water/soil. At present, the MICP reinforcement technology still has some problems, including solidification uniformity, soil durability, economic benefits, environmental safety, and sustainability. To solve these problems, it is necessary to further integrate microbiology, soil mechanics, materials science, environmental science, and other disciplines to conduct in-depth research, which will help deepen the understanding of MICP reinforcement technology, promote MICP technology to achieve more comprehensive development in the engineering geological field, and further promote application of this technology.

The recharge and discharge of groundwater are mainly vertical surface infiltration recharge, evaporation discharge (evaporation can be shown as negative value of infiltration) and lateral surface water recharge and discharge. One of the most basic problems in hydrogeology is the evaluation criteria of sustainable exploitation of groundwater, which involves the increment of recharge and the decrease of discharge. Therefore, the prediction model of groundwater exploitation must include the above two kinds of recharge and discharge factors, otherwise the evaluation of groundwater cannot meet the requirements. However, the classic Theis unsteady well flow model (1935) only involves the recharge and discharge of the side boundary, and does not considers the surface infiltration recharge of the upper boundary, even when groundwater is pumped near the river. In this way, the analytical model cannot be basically used for prediction, and can only be used for well flow test to obtain the aquifer parameters in dry season. Therefore, the goal of this paper is to develop the Theis unsteady well flow model with surface infiltration recharge. For the problem of phreatic flow, the equation of groundwater flow cannot be established by using head as the dependent variable in a confined aquifer. We use the potential function of the second linearization method to establish groundwater flow equation in the phreatic aquifer. For the solution of the generalized mathematical model of the complex hydrogeological problem with rainfall infiltration and a pumping well, we adopt the method of decomposing it into several simple sub-models and synthesizing them into the solution of the original complex mathematical model. Based on the principle of mass conservation and assuming that the seepage obeys the Darcy’s law and satisfies the Dupuit's assumptions, the differential equation of groundwater flow is established. Then, for the well flow problem with uniform and stable infiltration recharge in two parallel rivers and two kinds of strip regions formed by a river parallel to an impermeable boundary, the general equation of groundwater flow and several kinds of water table equations under specific conditions and their flux equations are obtained. In addition, the “boundary to boundary reflection method” is proposed and applied to solve the same problem in a strip of region between a river boundary in parallel to an impermeable boundary, which reduces many derivation processes. Finally, as a preliminary application of the above theoretical results, it is also an important application, that is, there is a pumping well near the river whose water quality cannot meet the requirements, and the critical flux equation of the pumping well is calculated on the premise of not absorbing the river water. The important and concise relation equation is obtained. The equation can also be used to calculate the critical pumping rate of pumping wells in coastal areas without seawater intrusion. In this paper, the groundwater flow network diagram at a certain time in the process of unstable well flow under the above conditions is given. Compared with the flow network of well flow near the river, which is commonly seen in the literature, the flow network has obvious characteristics.

The rough back of a wall causes the deflection of the soil stress direction behind the wall. At present, there are few studies on the influence of the deflection of the soil stress direction on the earth pressure in cohesive soils. For this reason, this paper firstly discusses the deflection law of the principal stress of the soil behind the wall, and adopts a layered formation of curved thin-layer elements along the principal stress trace. By analyzing the force of the curved thin-layer element, the static balance equation of the curved thin-layer element is established, and the formula for the distribution of the earth pressure of the cohesive soil along the wall height in the translational mode is derived, and the new analysis method of the cohesive earth pressure is obtained. Finally, the method in this paper is compared with the actual measurement results and the existing theory and the parameters are analyzed to verify the reliability and rationality of the method in this paper. The research results show that the calculation results considering the effect of wall-soil friction can more accurately reflect the distribution law of cohesive soil along the wall height; the magnitude of earth pressure decreases with the increasing cohesion. With the increase of wall-soil friction angle soil, the pressure resultant force gradually decreases, and the height of the point of application increases slowly.

How to identify deformed landslides in advance and conduct early risk assessments on them has become a research hotspot in the field of geological disaster prevention and control. In response to the above problems, the Jiangdingya landslide in the Bailong River Basin in Zhouqu is taken as a back analysis case, and a comprehensive study of the early identification and risk assessment of the landslide is carried out. In this paper, a full-process analysis method is proposed, which combine the small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) technology interpretation, geo-mechanical analysis and dynamic process simulation. The research results show that the SABS-InSAR technology interpretation can effectively identify the range of the Jiangdingya landslide and its early deformation. It may be preliminarily determined that the failure mode of the Jiangdingya landslide is trailed and the plane characteristics of the landslide body is generally about 680 m in length and 210 m in width. Based on the early identification information and through geo-mechanical analysis, it is finally identified that the instability problem of the Jiangdingya landslide is a typical deformation problem of the front edge of the old accumulation layer landslide. The failure mode is the traction slip failure, the average thickness of the landslide body is in about 35 m, the overall slope of the sliding bed is relatively slow, and the moving speed is not large after instability. On the basis of the above analyses, a Coulomb friction model that conformed to the sliding friction characteristics of the Jiangdingya landslide body is selected. Based on the depth integral continuum equation, the dynamic process of the Jiangdingya landslide body is calculated and the speed of the landslide body is monitored. In terms of velocity monitoring curves and accumulation pattern, the sliding velocity of the landslide body is not large, the maximum value is about 2.2 m/s, the overall performance is pushing the Bailong River channel, and the possibility of blocking the river is relatively small. In addition, when the displacement of the front edge of the Jiangdingya landslide body is completed, the speed of the landslide body from the front edge to the rear edge quickly drope to zero, and the movement process is characterized by the traction movement. The analysis results of the Jiangdingya landslide in this paper are consistent with the actual event of the Jiangdingya landslide. The comprehensive analysis method and research model can provide a good reference for the early identification and risk assessment of similar landslides in the Bailong River Basin in Zhouqu county.

The Baqu glacial lakes outburst debris flow is close to a station of the Sichuan-Tibet Railway, which may threaten the construction and running of the railway. In this paper, the methods of in-site investigation and remote sensing were used to identify the basic geological characteristics of the Baqu gully. The kinetics parameters of debris flow were calculated by using the code-design-formulae method. Meanwhile, the stability of barrier dams of 7 glacial lakes in Baqu was evaluated based on the dimensionless blockage index (DBI). The results show that the DBI value of the 1# barrier dam was in the unstable region, and the DBI value of the 3#, 4# and 6# barrier dams were between the unstable region and the stable region, and there was a possibility of outburst. In this paper, we used RAMMS, a single-phase flow numerical method, to simulate and analyse the evolution process of glacial lakes outburst in the Baqu gully under 4 scenarios. The simulation results show that the evolution process is divided into 4 stages: initiation, confluence, runout and deposition, which lasted for 4.5 hours. The results also show that the maximum velocity, depth and discharge of the debris flow at the mouth of the channel were 5.92 m/s, 4.35 m and 1 954.42 m3/s (5.1 times of that of the rainstorm debris flow), respectively, under the condition of glacial lake 1#—4# and 6# outburst. In addition, the influence area of outburst flood in 4 scenarios affected the proposed station, and the maximum depth was 1.91 m, 3.36 m, 1.53 m and 4.35 m, respectively. Therefore, in the design of the station, it is necessary to take engineering measures such as drainage canal or diversion dike for protection and treatment, so as to ensure the safe running of the station. The above results can provide reference for the line selection of the Sichuan-Tibet Railway and the prevention and control of glacial lakes outburst debris flow in the Eastern part of the Qinghai-Tibet Plateau.

Located in east-central Qinghai-Tibet Plateau, the Sichuan-Tibet traffic corridor is one of fastest uplifting and geomorphic evolution regions on the earth. Under the coupling of internal and external dynamics, the landslide in this region is extremely developed, which seriously restricts the planning and construction of highways, railways and hydropower projects. Based on the data collection and analysis of regional geological data, this paper selects lithology, slope gradient, aspect, slope shape, topographic relief, terrain roughness, fault density and distance to rivers as contributing factors. Combined the advantages of traditional information value method and logistic regression, this paper uses the logistic regression-information value method to evaluate the landslide susceptibility of the study area. Through the multi-collinearity test and significance test of the contributing factors, it is found that the selected contributing factors have no multi-collinearity and have a significant impact on the occurrence of landslides. ROC curve is used to test the results of landslide susceptibility, and the AUC value is 0.81, which shows that the model can well predict the occurrence of landslides. The results show that the high risk areas in the study area mainly occur in the regions of the Longmenshan fault zone, Jinshajiang fault zone, Lancangjiang fault zone, Nujiang fault zone and Bianba-Luolong fault zone, as well as on the sides of deep valleys of large rivers with steep slope and large topographic relief. The middle risk areas widely exist on both sides of the tributaries of large rivers. The results are helpful in understanding the development and distribution of landslides in the Sichuan-Tibet traffic corridor, and also provide a scientific basis for the project planning and construction, disaster prevention and mitigation in the study area.

Evapotranspiration is the link of water and energy transfer in the continuum of groundwater, surface water, soil, plants and the atmosphere (GSSPAC). Evapotranspiration is also a key in the study of land surface water balance. Affected by meteorological conditions, geological landforms, hydrogeological conditions and human activities, the mechanism of evapotranspiration process is complex, and its temporal and spatial variability is quite large. Based on many published journal papers, this paper comprehensively analyzes water resources and observation methods for evapotranspiration proposed by scholars at home and abroad. The results show that (1) surface water (rivers, lakes, etc.), soil water, groundwater and vegetation intercepted water are the major water sources of evapotranspiration. (2) The methods for measuring evapotranspiration can be divided into hydrology method, plant physiology method, micro-meteorological method and isotope method. These methods have advantages in studying the process and driving mechanism of evapotranspiration. (3) Different evapotranspiration measurement methods are suitable for different spatiotemporal scales, and more reliable evapotranspiration data can be obtained by integrating various measurement methods. According to the current situation of evapotranspiration researches, the next step is to strengthen the coupling mechanism researches of water transport in the GSSPAC system, and strengthen interdisciplinary researches to further clarify the interaction mechanism of water, energy and material cycle and flow. In addition, through the construction of monitoring network on different climate and geomorphic units, we can gain basic data of evapotranspiration variation under the interaction of multiple influencing factors, which can support large-scale and refined evapotranspiration researches.

An aquitard is an important part of an aquifer system. It is always difficult to determine the hydrogeological parameters of the aquitard. Traditional laboratory tests are difficult to overcome the influence of stress state and environmental change on the aquitard layer parameters. Therefore, evaluation of hydrogeological parameters under in-situ state is of great significance. This article selects a silt layer in the Hohhot Basin, and primarily designs and carries out pumping tests and solute transport tests. The unstructured grid with the controlled volume finite difference method is used to establish a 3D coupling model of groundwater flow and solute transport. Groundwater levels and concentration data are used to estimate the hydrogeological parameters of the aquitard. The results show that the variation in groundwater levels and solute concentrations in the pumping wells calculated by the model can fit well with the actual observation data, and the coefficient of permeability of the pumping aquifer identified by the model (4.8 m/d) is similar to the analytical result (4.17 m/d). The numerical model conforms to the actual hydrogeological conditions. The vertical hydraulic conductivity of the aquitard studied in this paper is 1.2×10−4 m/d, and the specific storage is 1.0×10−5 m−1. The method presented in this paper may provide references for the parameter determination of an aquitard.

The Prandlt formula is often used to calculate the anti-uplift stability of foundation pits in deep soft soil areas, which often fails to meet the specification requirements and brings great confusion to the design of foundation pit support. Based on the analysis of the difference in mechanical boundary conditions between the foundation pit excavation and the Prandlt formula for calculating the foundation bearing capacity, this paper points out the shortcomings of the improved calculation methods such as the Prandlt formula, critical width method, and takes into account the shear strength of the soil inside the foundation pit method, and puts forward an improved calculation formula considering the shear effect of the soil inside and outside the foundation pit support. Through sensitivity analysis of each parameter of the four calculation formulas, it is found that the internal friction angle is the most important factor affecting the stability of foundation pit wall bottom against uplift. The excavation depth and the insertion depth of the supporting body are the main influencing factors, the cohesion of soil body is the secondary influencing factor, and the influence of soil weight can be ignored. The friction angle of soft soil is small. Under certain excavation depth, the stability against uplift of foundation pit wall bottom can be guaranteed only by increasing the insertion depth. Therefore, considering the favorable effect of shear strength of soil on the inner and outer sides of foundation pit support, the foundation pit design can be reasonably optimized. This paper also verifies the rationality of taking into account the shear strength effect of soil on the inner and outer sides of the foundation pit support through engineering case studies. At the same time, according to the statistical analyses of wall bottom stability calculation of many projects, it is pointed out that the current standard is too high and unreasonable in soft soil areas. It is suggested that the standard limited value of the standard calculation method should be appropriately reduced on the basis of accumulated engineering experience.

Ammonia, nitrite and nitrate are typical pollutants in shallow groundwater and in the vadose zone, and their migration and transformation processes are highly concerned. In recent years, new studies have focused on the three-nitrogen in the groundwater level fluctuation zone. This paper comprehensively uses the literature measurement analysis method to quantitatively analyze the related research trends, and systematically summaries the latest research results of the formation and characteristics of the groundwater level fluctuation zone, the migration and transformation process of the three-nitrogen and their biogeochemical processes in the fluctuation zone. The results show that environmental indicators such as soil moisture content, redox potential, contents of dissolved oxygen and organic matter in the groundwater level fluctuation zone have remarkable zoning rules, and the microbial community structure and functional genes are more diversified with obvious layers. As the groundwater levels fluctuate, the three-nitrogen in the vadose zone is easy to leach into the groundwater and migrate. As the groundwater levels rise, nitrification weakens, denitrification enhances, and as the groundwater levels drop, nitrification enhances, and denitrification weakens. Finally, this paper prospects the research hotspots and directions in the future: (1) the groundwater chemical evolution analysis is combined with the high-throughput sequencing method of molecular biology to explore the three-nitrogen transformation and microbial action mechanism in the groundwater level fluctuation zone. (2) In addition to nitrification and denitrification, the researches on dissimilation reduction, assimilation reduction and anaerobic ammonia oxidation processes are increased. (3) The groundwater level fluctuation process with more scenarios and influencing factors are analyzed, and the key influencing factors of the three nitrogen transformation in the groundwater level fluctuation zone are identified.

In recent years, the unloading of excavation engineering activities such as foundation pits and tunnels has caused excessive lateral deformation of cohesive soil, which result in more and more engineering accidents. At present, the inclinometer is often used to monitor the horizontal displacement of the soil around the foundation pit. However, due to the special engineering properties of soft soil, the inclinometer cannot be driven to deform with the soft soil during monitoring. The effect of monitoring is often unsatisfactory and inaccurate to reflect the true deformation. Therefore, it is necessary to strengthen the research of lateral deformation monitoring technology of soil in the construction of excavation unloading engineering. In this paper, based on the directional characteristics of the deformation of magnetic minerals under loading, the magnetic fabric test is used to study the magnetic anisotropy of the cohesive soil sample after unconfined compression test and then to compare with the results of the confined one. The paper then discusses the mathematical relationship between the main magnetic susceptibility value and the strain as the consequence of the analysis of the influence of the axial stress and the moisture content of soil on the magnetic anisotropy under unconfined compression. Finally, the feasibility of the calculation of the law of force and the deformation from the magnetic anisotropy of the cohesive soil is explored. The research results show that the deformation of the cohesive soil under force has good consistency with its orientation of magnetic mineral. This understanding has important theoretical significance and practical application value for effectively monitoring the deformation of soft soil around unloading projects in soft soil areas.

The application of steel short piles in practical engineering is restricted due to its unclear bearing mechanism. However, due to advantages such as low cost, high strength, minimal soil displacement, easy construction, and convenient transportation, these piles are widely used in photovoltaic power projects in desert areas. In order to accurately reveal the horizontal and vertical bearing performance of steel piles in desert regions, horizontal load tests for different types of steel piles (including cross-sectional shape, cross-sectional area, and burial depth) and vertical compression and uplift load tests were conducted in a specific sandy site. The study analyzed the influence of parameters such as cross-sectional shape, cross-sectional size, and pile length on the bearing performance of steel piles. Research findings indicate: (1) The horizontal bearing performance of pipe piles and H-shaped steel piles is signifi-cantly better than that of C-shaped steel piles and trough-shaped steel piles. Compared with C-shaped steel piles and trough-shaped steel piles, pipe piles and H-shaped steel piles exhibit advantages in resisting wind loads, with the horizontal bearing performance of H-shaped steel piles closely related to the cross-sectional size and pile length. (2) The vertical bearing capacity of pipe piles and H-shaped steel piles is also significantly better than that of C-shaped steel piles and trough-shaped steel piles. Moreover, the compressive and tensile bearing performance of H-shaped steel piles is positively correlated with cross-sectional size and pile length. When the length of pile is the same, the vertical bearing capacity of H-shaped steel piles is similar to that of pipe piles. (3) The bearing performance of H-shaped steel piles is more prominent compared to other pile types (C-shaped steel piles, trough-shaped, and pipe piles) in sandy soil area. Furthermore, when compared with traditional pipe piles, H-shaped steel piles requires less materials and can create greater economic value, making them an excellent choice for the foundation of desert photovoltaic bracket foundations. The research results in this paper have reference for engineering applications.

With the increasing attention paid to groundwater contamination issues, the increasing demand was needed for small-scale site contamination hydrogeological work. The site contamination hydrogeological work has some particularities, which includes small scale, high resolution, and not only studying of contamination processes with the source leakage, but also studying of contaminant removal under the remediation state. Especially the transportation and reactions in the aquifer for in situ injected fluids (gases, liquids and microbes) of remediation agents need to be concerned greatly. The traditional large-scale hydrogeological work is difficult to meet the special needs above, therefore, it is necessary to propose “site contamination hydrogeology” for site-scale groundwater pollution risk management. This paper focuses on the characterization of stratigraphic media and pollution plumes in small-scale contaminated site, quantitative description of the pollutant-water-rock reactions, and the role and influence of pollutants in heterogeneous strata in multiphase systems. Finally, the main research content and key issues for site contamination hydrogeology were proposed, including: high-resolution characterization of sites at small scales, quantitative description of the physical, chemical, and biological reactions of pollutants in the underground environment during pollution and remediation processes, the migration and transformation of pollutants at the site scale in underground environmental media, transport and reaction of remediation agents (additives) in underground environments, and the pollution control and remediation in heterogeneous and low-permeability formations.

The retaining piles for foundation pits are usually arranged with equal pile lengths. However, in foundation pit projects in deep and soft soil areas, the retaining piles need to be embedded in good soil below the soft soil, so the pile lengths are longer. The economy is poor when the pile lengths are arranged with equal pile lengths. In order to examine the effect and performance of long and short pile combined support with partial retaining piles embedded in good soil in deep soft soil foundation pits, current design methods are used to calculate the structural internal force and deformation of retaining piles under the conditions of full length pile support and full short pile support. Therefore, it is estimated that the deformation of retaining piles under the condition of using long and short pile combined support should be between full length pile support and full short pile support. Through 3D numerical simulation, a comparative analysis is conducted on the combined support of long and short piles with different lengths to determine the appropriate length of short piles, and the analysis results are used to guide the actual project design and monitor the project. The research results show: (1) The length of the short pile supported by the combination of long and short piles can be taken as the second inflection point for calculating the bending moment of the retaining pile under the condition of full length pile support, achieving joint stress and coordinated deformation of the short pile and long pile. (2) The design and calculation method for long short pile combined support based on current design and calculation software presented in the paper is feasible. (3) The design method of long and short pile combination support can effectively save project costs. The monitoring data show that the application of long and short pile composite support in the project is successful, and the research results can provide references for deep soft soil foundation pit engineering.

The current studies of the cylindrical cavity expansion in sand still lack a deeper analysis for the results obtained in sands with different initial states. In addition, most of previous studies have not considered the influence of the shape of yield surface of sand, which made their results difficult to be popularized in different types of sand. In order to obtain a general solution to expansion of cylindrical cavity in sand under the drained condition, a unified state parameter model - clay and sand model (CASM) with Rowe’s stress–dilatancy relation is used to describe the characteristics of elastic-plastic deformation of sand. By employing that large strain occurs in sand and introducing an auxiliary variable, several partial differential equations to calculate the effective stress and specific volume of sand in the elastoplastic zone are derived on the basis of the Lagrangian description.Under the elastic-plastic boundary conditions and the elastic solution of cylindrical cavity expansion, a semi-analytical solution for drained cylindrical cavity expansion in sand is obtained by solving the governing equations numerically. The results show that the solution of cylindrical cavity expansion established in this paper can be used in many types of sand by changing the values of stress-state parameter n and spacing ratio r* to select an appropriate shape of yield surface of sand, and the greater the values of n, r* are, the greater the initial yield deviatoric stress of loose sand and the subsequent expansion pressure, but these situations will reverse in medium dense and dense sand. The ultimate expansion pressure increases with the decreasing initial state parameter of the sand, and together with the volume variation rule of sand changes from always contraction into dilatation first and then contraction, the radius of the elastic-plastic zone decreases first and then increases, and the hardening response of sand changes from always hardening into softening first and then hardening. The ultimate expansion pressure increases with the increasing coefficient of earth pressure at rest of sand, but the volume change law of sand has little change. This study provides a reliable theoretical support for the analysis of related geotechnical engineering problem.

Collapsible coefficient is an index to evaluate loess collapsibility, which is measured by laboratory test with collected intact samples. Collapsible coefficient varies with normal pressure loaded in test. It is better to use the real normal pressure in foundation when measuring the collapsible coefficient, but for reasons of convenience, the pressures are always designated as definite values in the codes or standards of construction in collapsible loess areas. However, the designated pressure for Q3 (Malan) loess in the standards is reasonable and applicable, while that for Q2 loess is still necessary to discuss. In this paper, the collapsible loess foundation of the Huaneng Electric Plant in Zhengning, Gansu Province is used as a case, the Q2-Q4 loess samples were collected in a 35.0 m deep shaft in 1 m intervals and the basic physical properties were measured in laboratory first. The collapsible coefficient is measured with the double oedometer method under low to high pressure for all the samples. Based on the test results, the collapsible coefficient with respect to depth determined with the present used GB 50025—2018 standard and the real pressure in foundation in the cases of various basement widths and basement pressures are compared. The results show that (1) the coefficient of collapsibility has a peak value. The initial collapse pressure and peak collapse pressure of Q3 loess are higher than those of Q2 loess. The peak coefficient of collapsibility of Q3 loess is higher than that of Q2 loess, which decreases with depth. (2) For Q3 loess, the collapsible coefficient and subsidence determined by the pressure of the present standard are close to those determined by the real pressure in foundation, while for Q2 loess, those determined by the pressure of the present standard in foundation deviates increasingly with depth to those determined by the real pressure. (3) Therefore, a modified test pressure for measuring collapsible coefficient of loess is proposed. It is demonstrated that the collapsible coefficients determined by the modified test pressure agree well with those by the real soil pressure.

Since 2019, the Ministry of Natural Resources has comprehensively promoted the research and development of universal equipment and the automatic monitoring and forewarning of geological hazard. As of June 2023, it has been applied to 55 000 potential points of geological hazard in 17 key geological hazard prevention provinces, and the national geological hazard monitoring and forewarning system has entered a rapid development stage. At present, the system receives more than 10 million monitoring data every day, and has made positive progress in massive data storage management, parallel processing of time series data, intelligent analysis of big data and multi-parameter risk early warning. However, there are many challenges in data security of the system, especially in data consistency, data tamper resistance and system reliability. On the basis of systematic research on the characteristics of the blockchain technology and its typical application in related fields, this paper proposes a “trusted data flow” technology based on distributed ledger and consensus mechanism, according to which the overall framework of “blockchain + NRWSL” is formed, and a prototype system is established. The test data show that the improved system can solve the problem of data inconsistency between provinces and Ministry of Natural Resources, identify and prevent illegal data tampering, ensure the stable operation of the system under multi-node failure conditions, and the overall performance loss of the system is less than 20%. The research results provide technical methods for the application of blockchain technology to geological hazard risk early warning systems at all levels in China, and also provide top-level design ideas for improving the security of geological hazard monitoring data and the early warning system.

Aiming at the problem of quality control of a deep mixing pile in construction process, this paper introduces a novel digital construction cloud platform incorporated in the equipment minor-disturbance four-axial soil mixing pile, realizing the real-time tracking and feedback in construction process. After inputting the parameter related to different strata into the platform, the variation of parameter is automatically controlled in construction. After inputting the threshold of underground pressure, the minor-disturbance to subsoil is realized with a measured soil lateral displacement and upheaving in millimeter scale. With a measurement of verticality of drill rod in real time, the pile verticality can be controlled to 1/250. The management cloud platform realizes a dynamic management of quality control for all parties in the construction. This practical results are beneficial to completely improve the construction quality of the deep mixing pile and digital construction level of soft soil.

Located in the city of Xianyang in Shaanxi Province, the Hanyang Mausoleum is the first fully closed underground museum in China and in the world. The fissure disease of its outer pit is developing, which seriously endangers the safety of the pit wall and the pit bottom cultural relics, and it is urgent to protect and strengthen the pit. In the past, more was learned about the disease and prevention of the ruins in the open air and semi-closed environment, while the completely closed environment was seldom examined. This paper takes the outer pit K21 of the Hanyang Mausoleum as the research object. The number and distribution characteristics of cracks are determined through field investigation. On this basis, the causes of cracks are studied and classified. The stability of pit wall and its influencing factors are analyzed by numerical simulation methods. The research results show that there are 53 cracks in the K21 outer pit, mainly occurring on the south and north sides of the surface and the pit wall. The surface longitudinal cracks are unloading cracks, the surface transverse cracks are dry shrinkage cracks, and the pit wall cracks are mainly structural cracks. The longitudinal unloading crack is the main reason for the reduction of pit wall stability. The earthquake, artificial load or the further development of cracks will lead to the pit wall to be unstable. It is recommended to use anchor bolts to reinforce the pit wall, and reset and pre-tighten the unloading cracks by applying prestress. This study is of important guiding significance for the investigation and protection of the fissure disease in the museum sites.

Collapse risk identification is the basis of collapse disaster prevention. High level collapse is characterized by sudden, hidden and large height difference, which brings great challenges to information collection, disaster identification and risk assessment. In order to solve this engineering problem, this paper takes the Jiulongxia high slope in the Bailong River basin as an example, Based on the 3D model of oblique photography, the establishment of high-level collapse identification index and its structural plane information extraction method, proposes a collapse risk assessment model combining stereographic projection qualitative analysis and InSAR quantitative analysis, and forms a whole process model of high level collapse identification and risk assessment combining collapse identification, stability analysis and deformation monitoring. The results show that there are 22 collapse dangerous rocks in the study area (including 7 high risk rocks, accounting for 32%, 11 medium risk rocks, accounting for 50%, and 4 low risk rocks, accounting for 18%), with a distribution height of 37 m – 640 m. High risk dangerous rocks are mainly concentrated in the prominent mountain mouth in the south, the eastern slope and the western slope toe. These analysis results are consistent with the historical data of highway disaster maintenance, which verifies the feasibility of tilt photography and InSAR technology in high level collapse risk identification. The results provide a basis and reference for the application of this technology in collapse disaster prevention.

Under the impact of climate change, significant changes have taken place in the ecological environment and water cycle of the Yangtze River source area. Soil water is an important component of the hydrological cycle, and a correct understanding of the spatial and temporal distribution patterns and environmental response mechanisms of soil water is the basis for a deeper understanding of the hydrological cycle and ecological environment changes in the Yangtze River source area. It is also of great significance for promoting the sustainable development of the Yangtze River source area. In this paper, based on ground in-situ observation data, combined with the latest long time-series and multi-sensor combined global soil moisture dataset developed by the European Space Agency (ESA CCI SM V07.1), the spatial and temporal evolution of surface soil water in the Yangtze River source area is revealed, and the impact mechanism of structural function and permafrost type on soil water is discussed. The results show that the surface soil moisture in the Yangtze River source area is mainly concentrated between 0.15 and 0.20 m3/m3, with the highest value occurring from June to October. In the vertical direction, the soil moisture content mainly shows an increasing-decreasing-stable trend from the surface to the deep soil layer, and the deep soil water has a significant lag characteristic relative to the surface, with a lag time of generally 1−2 months. In the horizontal direction, the surface soil moisture overall shows a southeast high and northwest gradually decreasing trend. The closer to the structural fault zone, the lower the soil moisture content, and with the increasing depth, it shows a certain aggravating trend. The surface soil moisture content in the permafrost area is higher than that in the neighboring seasonal frozen soil area. The fluctuation range of the surface soil moisture content in the seasonal frozen soil area is smaller than that in the permafrost area. Over the past 40 years, the surface permafrost has shown a trend of gradual melting, and since 2000, the melting of permafrost has intensified, with a significant increase in surface soil moisture content. The results of this study are of great theoretical significance for the in-depth understanding of the hydrological cycle and ecological environment changes in the Yangtze River source area, and can provide a reference basis for the hydrological cycle and water resources management in the Yangtze River source area.

Chemical weathering of silicate minerals is an important source for Ca, Mg, Na and K. However, in comparison with other major elements (e.g., Ca, Mg and Na) in waters, how K behaves during water-rock interaction remains poorly understood. Recent studies have shown that large K isotopic fractionation could occur during various processes of low-temperature water-rock interaction such as chemical weathering and adsorption, making K isotopes gradually become a powerful tracer for the sources, migration and transformation of K cycling in the subsurface. This overview summarizes K isotopic compositions of major reservoirs at the Earth’s surface, including upper continental crust, hydrosphere and other reservoirs (plants and fertilizers). We conclude that 41K is enriched in hydrosphere than upper continental crust, providing an opportunity to identify the K source in groundwater.The magnitudes and mechanisms of K isotope fractionation during common water-rock interaction processes are also summarized (i.e., silicate dissolution, secondary mineral formation, adsorption, cation exchange), demonstrating that limited K isotope fractionation occurs during silicate dissolution, while clay formation results in enrichment of 41K in waters and adsorption and cation exchange leads to depletion of 41K occurring in waters. These different behaviors of K during these water-rock interactions provide an opportunity for tracing the migration and transformation process of K in groundwater. This paper presents the latest research that applied K isotopes to trace silicate weathering and water pollution. Since K isotopes are an excellent tracer for silicate weathering, they can be used to reveal the sources, migration and transformation of K cycling in aquifers with abundant CO2. Additionally, the distinguishable behavior of K isotopes during chemical weathering, clay adsorption and cation exchange can be used to identify various water-rock interactions. Future K isotopic studies in the field of hydrogeochemistry should focus on: (1) constraining the contribution of multi-endmember control on sources of potassium in groundwater; (2) quantifying K behavior during long-term groundwater circulation; and (3) using multiple isotopes to trace carbon cycle-related processes.

The drilling methods and the partitioning inter-well tracer tests which are often used to characterize dense non-aqueous phase liquids (DNAPL) source zones cost a lot. Compared with common methods, the single- well “push-pull” partitioning tracer tests not only save money, but also reduce the disturbance to the contaminated site, which can be used to estimate the residual DNAPL. However, the accuracy of this method in estimating residue DNAPL has not been quantitatively verified. To solve the problem, this paper analyses the influence of several factors on estimating the accuracy of residual DNAPL based on the numerical method, including tracer type, the injection and pumping rate and contaminant source zone architectures. The results display that Hexanol with a smaller partition coefficient than DMP can be selected for tests, as the tracer are recovered more fully, which can result in the average accuracy of residue DNAPL estimated to increase by 35.11%. When the injection rate of the tests increases from 100 m³/d to 130 m³/d and the pumping rate increases from 120 m3/d to 150 m3/d, the tracer can expose to a larger contaminant source area so that the average accuracy of the homogeneous source zones increases from 42.45% to 60.26% while the average accuracy of the heterogeneous source zones increases from 27.69% to 48.72%. The increase of the complexity of the source zone architectures will hinder the tracer migration, and the average accuracy of the heterogeneous source zones is 13.15% lower than that of the homogeneous source zones. The single well “push-pull” partitioning tracer test is more suitable for the ganglia-dominated contaminant source zones, and the average accuracy of the ganglia-dominated contaminant source zones is 15.74% higher than that of the pool-dominated source zones. The single-well “push-pull” partitioning tracer tests combined with numerical analysis can effectively estimate the distribution of residual NAPL, and are recommended for use in the fine investigation of DNAPL contaminated sites, so as to provide a reference for the risk assessment and the site remediation.

Deep heterogeneous carbonate reservoirs have become more and more important in the deep exploration of geothermal resources in China. The essential seismic exploration technology has many difficulties, such as serious attenuation of deep energy, low signal-to-noise ratio, difficult imaging of inner basement in tectonic uplift areas. In order to acquire high-quality deep seismic exploration data, a large number of vibroseis excitation parameters and geophone receiving parameters experiments have been received in a typical areas of the Central Hebei Plain in North China. On the basis of a large number of field experimental data, a qualitative analysis of the original single-shot records is carried out, and quantitative analysis is also carried out from the aspects of frequency band energy, inter-channel frequency, signal-to-noise ratio, etc., to study the parameter selection such as the number of vibroseis, sweep frequency, sweep length, vibration times, driving amplitude and geophone combination mode, which can affect the quality of the seismic data. In this paper, the field construction parameters for 2D seismic exploration of deep carbonate reservoirs in the North China Plain are optimized as follows: 4 sets of 28 tons vibrate 4–6 times, 75% driving amplitude, non-linear sweep (slope –3), 6–84 Hz sweep frequency, and 12 s sweep length. The quality of the single-shot records and data processing profiles are greatly improved after parameter optimization, which can be more clearly divided into the bottom interface of the Gaoyuzhuang Formation of the Jixian System and the top interface of the Archean Erathern in the Niutuozhen uplift tectonic area. The optimized seismic acquisition parameters are of certain reference and guiding significance for deep seismic exploration in sedimentary basins.

The exploitation and utilization of clean energy is a resource and environmental issue of common concern for global sustainable development. As a vital strategic and sustainable future energy, hot dry rock (HDR) has attracted more and more attention. In this paper some thoughts on the future research direction of HDR resources in China are provided based on a worldwide experience summary, hoping to provide a useful reference for the future exploration and engineering development of HDR. Since the concept of HDR was put forward in the 1970s, the number of worldwide HDR construction has been increasingly growing. Although a lot of theoretical and technical breakthroughs have been made, only a small fraction of projects still in operation due to the lack of sustained financial support, induced microearthquakes and other issues. At present, the global development of HDR is gradually entering a new stage of exploration, and the basic theories of HDR to tackle the key problems are strengthening around the world. Since 2012, the China Geological Survey has organized and implemented the nationwide terrestrial HDR resources survey, evaluation, exploration and development, and significant stage progress has been achieved. A series of fundamental maps have been compiled, such as terrestrial heat flow value, curie surface depth, distribution of acidic rock, and heat-controlling structure in China. The resource potential of terrestrial HDR in China has been preliminarily estimated and a sounding basis for the target site selection is provided. HDR exploration and evaluation have been carried out in typical areas of Qinghai, Shandong, Hebei, Shanxi and Jiangsu provinces, and a breakthrough has been achieved in the Gonghe Basin of Qinghai. The first HDR resources exploration and production demonstration project in China was carried out in 2019, which made a series of meaningful outcomes in deep HDR exploration, high-temperature hard rock drilling, large-scale reservoir stimulation, reservoir connectivity and flow circulation, organic Rankine cycle (ORC) power generation, etc. The large-scale reservoir stimulation was carried out in 2020, and the first power generation test was completed in 2021. In general, the global exploration and development of HDR has made great progress. Practice has proved that HDR resources are a promising green energy and are expected to become an inexhaustible energy support for the world in the future. However, there is still a large gap between the existing path of HDR development and utilization and the economics of its supporting technologies compared with commercial development expectations at present. Although the development of HDR resources in China has achieved a breakthrough from “0” to “1”, there is still a long way to go from the international level. In order to solve the problems of large-scale and economic development, it is still needed to promote disruptive technological innovation in high temperature hard rock drilling and completion, fine characterization of deep reservoirs, safe large-scale reservoir construction, efficient heat transfer and heat recovery and other aspects.

Land subsidence has become a serious issue in Cangzhou for a long time. In order to make reasonable use of groundwater resources, it is necessary to establish a warning groundwater level under the premise of controlling the development of land subsidence. How to quantitatively determine the critical gorundwater level (CWL) for comprehensive control of land subsidence? In allusion to this scientific problem, this paper takes the soil samples of three typical settlement areas in Cangzhou as the research object, and analyzes the formation consolidation characteristics. By correlating the stratum thickness, we improve the method of calculating the CWL with the previous consolidation pressure. Based on the monitoring data of land subsidence and groundwater level in Cangzhou for many years, the comprehensive quantitative evaluation of the CWL in Cangzhou are carried out. The results show that the soil within a depth ranging from 0 to 150 m in Cangzhou is normally consolidated or under-consolidated, and the soil below the depth of 150 m is generally over-consolidated. The inelastic water release deformation is an important factor affecting the change of land subsidence rate in this area. Using the improved method, the CWL in Cangzhou, Suning and Dongguang is 66.8 m, 67.5 m and 67.8 m, respectively. Based on the data of the cumulative land subsidence and groundwater level change in the urban of Cangzhou, we obtain the exponential function relationship between the cumulative land subsidence and groundwater level. The subsidence rate is taken as the index, and the critical groundwater level in the urban of Cangzhou ranges from 65 to 70 m. On the basis of verifying the consistency of the calculation results of the two methods, we determined 65 m as the critical groundwater level for the prevention and control measures of land subsidence in Cangzhou. The results provide a reliable basis for the local government to formulate a reasonable groundwater exploitation plan.

During the process of developing and utilizing geothermal resources, various challenges are encountered. One such challenge is the decrease in temperature and pressure of the geothermal reservoir as a result of the increasing geothermal exploitation and duration. In addition, the discharge of geothermal tail water poses a risk of thermal pollution, leading to environmental concerns. To address these issues effectively, reinjection of geothermal fluids into the reservoir can be implemented as a viable solution. Prior to initiating the geothermal development and utilization, it is crucial to conduct scientifical and rational planning of the layout of production and reinjection wells. This involves exploring optimal strategies for the production-reinjection scheme that prevents the premature thermal breakthrough and maximize the efficient utilization of geothermal resources, thereby extending the lifespan of the geothermal reservoir. The Fengpei Basin, a Cenozoic rift basin that developed since the Paleogene period, exhibits a widespread distribution of geothermal reservoirs, primarily composed of the Ordovician limestone with karst and fracture characteristics. Building upon the geothermal resource exploration results in the Anguo Town in Peixian County in Jiangsu Province, this study utilizes key parameters obtained from pumping tests and reinjection experiments, such as well spacing and the reinjection-to-production ratio. This paper establishes a 3D coupled numerical model of geothermal water seepage and heat transfer by using the Feflow6.2 software. The recoverable reserves of geothermal fluid within the geothermal reservoir are simulated and predictd, specifically the Ordovician limestone formation. Furthermore, a simulated optimization of the development and utilization scheme for the production-reinjection wells is conducted. The results reveal that an appropriate well spacing of 389 m between the producing well (RPX01) and the reinjection well (RPX02) is recommended. Moreover, the reinjection-to-production ratio, namely the ratio of average aquifer hydraulic conductivity, is determined to be 1.29, supporting a sustainable approach of one-for-one pumping and reinjection. With a stabilized drawdown of 50.61 m, the production well has a capacity to recover 1000 m3/d of geothermal resources. Under the conditions of a production rate and a reinjection rate of 1000 m3/d, as well as a reinjection temperature of 40 °C, the simulation predicts a decrease in groundwater level by 45.49 m and a temperature reduction of 1.44 °C after ten heating seasons. This represents the optimal cyclic development and utilization scheme among the simulated scenarios. The above results provide a scientific basis for decision-making in the construction of the clean energy heating demonstration area in rural northern Jiangsu. They contribute to the establishment of a scientifically sound and sustainable approach for utilizing geothermal resources, while considering the challenges associated with the thermal breakthrough and the environmental impact of geothermal tail water discharge.

The consequences of landslide waves are far beyond the landslide itself that has attracted widespread attention. The prediction and evaluation of this kind of disaster has always been difficult, and the precise description of landslide surge motion characteristics and energy conversion law is the key and premise to solve the problem. In this paper, we use gravel to mimic granular landslide and establish a 3D landslide wave model in a rectangular flume, aiming to analyze how the landslide volume, velocity and water depth affect landslide accumulation, wave characteristics and energy conversion. The results show that (1) the waves generated by solid impacting the water are affected by the landslide size and shape. Slides with larger thickness and faster speed tend to produce nonlinear transition wave, and thin and slow slides generally produce nonlinear oscillation wave. (2) The volume effect and velocity effect based on the test reveal that the surge scale of a certain water depth is positively correlated with the landslide volume and velocity. The water depth effect explains the differences of waveform and velocity under a certain wave energy. Statistic results show that under the shallow water conditions, surge height on average is 67% higher and wave speed on average is 51.17% higher than those under the deep water conditions. (3) The conversion rate between landslide energy and wave energy ranges from 1.00% to 3.07%. 3D experiments encounter more energy dissipation due to diffusion and its conversion rate is lower than that in the 2D experiments. This study discusses the kinematic characteristics of granular landslide, first wave generation, propagation and inundation, and proposes the basic law of energy conversion between landslide and water. It id of certain value and significance for landslide wave hazard prevention and mitigation.

With the implementation of the South-North Water Diversion Project and the implementation of groundwater suppression, the local groundwater levels in the North China Plain have gradually rebounded. However, there is a lack of systematic studies of the trends of groundwater balance elements and their impacts on the ecological environment. This paper takes the Baoding Plain, a typical area in the North China Plain, as an example, and uses the water balance method to calculate the groundwater recharge and discharge terms, applies the factor analysis method to analyze the causes of the changes in groundwater balance elements from 1975 to 2019, and calculates the amount of recoverable and suppressed groundwater resources by using the optimal exploitation coefficient method, which provides a basis for the development and utilization of groundwater resources in the study area. The results show that in the past 40 years, the groundwater recharge term was smaller than the discharge term in the Baoding Plain, which is in a negative equilibrium state, and the main change elements are canal irrigation infiltration, canal system seepage, well irrigation return, river seepage, rainfall infiltration and artificial exploitation. The main factor affecting the change of groundwater equilibrium elements is human activity, with a contribution rate of 77.2%. After the groundwater recharge and discharge imbalance is slowed down, the increase of groundwater level burial depth becomes smaller, the area of groundwater level depression cone gradually decreases, and the area of the Baiyangdian wetland gradually recovers. The optimal exploitation coefficient of groundwater resources in the Baoding Plain is determined to be 0.64, the exploitable groundwater resources range from 8.89×108 to 11.35×108 m3/a, and the amount of compression exploitation ranges from 2.68×108 to 5.14×108 m3/a. The research results can provide a scientific basis for the sustainable development of groundwater resources and ecological environment in similar areas.

Urban underground space resource is one of the vital resources of the city. Shenzhen is the city with limited land resources and urgently needs to carry out geological suitability evaluation of underground space to guide the development and utilization of underground space. However, the development of underground space resource is restricted by a variety of geological factors. It is necessary to use appropriate methods to evaluate the geological suitability of underground space development. Taking the Nanshan District of Shenzhen as the study area, this paper proposes a constraint evaluation system that takes the constrained geological factors as the first-level evaluation index and combines the geological background of the study area with the planning of underground space resources utilization in Shenzhen. The geological suitability of shallow underground space (0−15 m) and sub-shallow underground space (>15−30 m) in the study area of the conventional system and constrained system is evaluated by using the empirical score evaluation method and fuzzy comprehensive evaluation method. The results show that (1) compared with the conventional evaluation system, the constraint evaluation system improves the overall weight of the constraint geological factors. (2) According to the evaluation results of the constraint system, the poor and unsuitable areas are mainly distributed in the fault zone, high incidence of geological disasters and surface water area, which is more consistent with the actual geological conditions of the study area. (3) Attention should be paid to the geological problems such as stratum instability and ground collapse caused by sand liquefaction in the unsuitable areas during the development and utilization of the key development zones in planning. Meanwhile, geological problems such as rock fragmentation and groundwater enrichment in the region of restricted active faults should be avoided reasonably. This study strongly supports the planning of underground space resource utilization in the Nanshan District of Shenzhen.

The Sichuan Basin located in the intersection of the Tethys−Himalaya and Pacific domains is a multicycle sedimentary basin surrounded by orogenic belts. The geothermal resources are good, but with complex geological structures. Geothermal conditions and heat generation models are different in different tectonic zones in the basin, which seriously restrict the geothermal exploration, development and utilization of geothermal resources. In this paper, the distribution of geothermal resources, characteristics of geothermal fluids, heat flow and geothermal gradients in the Sichuan Basin are comprehensively analyzed by collecting the existing geothermal and petroleum exploration and development data. The geothermal reservoirs and caprocks, the burial depth and the resource conditions of different types of the basin-mountain structure areas in the Sichuan Basin are analyzed. The suggested exploration target for exploration and development are proposed in different tectonic units of the Sichuan Basin. The results show (1) the terrestrial heat flow values in the Sichuan Basin and its surrounding areas are from medium to low, and the geothermal gradient varies between 16 °C/km and 30 °C/km. The terrestrial heat source is obviously controlled by active faults and basement structure, and the hydrothermal systems are conductive and belong to the low-moderate temperature geothermal resources in the Sichuan Basin. (2) The distribution of geothermal resources in the Sichuan Basin is mainly controlled by basin structure, stratigraphic distribution and hydrologic conditions. (4) There are at least 4 karst-type geothermal reservoirs in the marine strata, and 1 − 2 glutenite-type geothermal reservoirs in clastic strata. Geothermal water is of SO4—Ca type and is brackish. The Middle-Lower Triassic and Middle Permian carbonate rocks are considered as the best marine reservoirs, especially in the eastern and western basin. Secondly, other marine karst-type geothermal reservoirs are selected for exploration. The continental clastic rocks should be cautious because their caprocks, groundwater recharge and heat source are worse than the geothermal conditions of the marine carbonate rocks. This study may provide important guidance for further promoting geothermal exploration, exploitation and utilization in the Sichuan Basin.

When using machine learning models for landslide susceptibility evaluation, the non-landslide sample points are usually selected randomly outside the landslide influence area, leading to a certain error. To improve the accuracy of landslide susceptibility evaluation, this paper couples the self-organizing map (SOM) neural network, information (I) model, and support vector machine (SVM) model, and proposes a SOM-I-SVM model-based method of landslide susceptibility evaluation, comparing with K-means clustering to verify the reliability of this model. The Maojian District of the city of Shiyan is taken as an example, and seven factors of the distance from water system, slope, rainfall, distance from structure, relative height difference, distance from road, stratigraphic lithology are selected by correlation and importance analyses of environmental factors to establish a landslide susceptibility evaluation system. Based on these, the graded information values of each factor are calculated and used as input variables for landslide susceptibility evaluation. The SOM neural network and K-means clustering are used to select non-landslide samples, and the sample data set is substituted into the I-SVM model to predict landslide susceptibility. The prediction accuracies of the four models, SVM, I-SVM, KMeans-I-SVM and SOM-I-SVM, are compared, and the area under the ROC curve (AUC values) are 0.82, 0.88, 0.90 and 0.91, indicating that the SOM-I-SVM model can effectively improve the accuracy of landslide susceptibility prediction.

The Shuitoushang landslide in Ershe in Qijiagou Village of Xinchang Town in Tongjiang County is a typical red-bed terrace landslide in eastern Sichuan. There are few studies on the seepage analyses of such landslides in this area, but similar slopes are widely distributed in the area. In this paper, on the basis of a large number of field investigations, surveys and data collection of disaster sites, the satellite remote sensing, UAV aerial photography, airborne LiDAR, indoor tests and other technical means are comprehensively used to analysis the landslide. Based on the mathematical model of Fredlund & Xing soil-water characteristic curve, the SEEP/W module in Geo-Studio is used to conduct the seepage analysis, and the analysis results at different time stages are coupled with the SLOPE/W module. Then the dynamic relationship between the stability coefficient, rainfall and time is obtained, revealing the deformation process and formation mechanism of the landslide. The results show that: (1) the continuous rainfall causes the groundwater level to rise and the slope stability to decrease, eventually leading to the overall instability and failure of the Shuitoushang landslide. (2) The deformation process of the landslide and the characteristics of groundwater exposure are basically consistent with the results calculated by Geo-Studio, indicating that the results based on Fredlund & Xing model can provide more accurate simulation results in similar areas. (3) Reclamation of terraced fields (paddy fields) will reduce slope stability. The results can provide theoretical support for hidden danger investigation and active prevention of similar landslide disasters in mountainous areas of Sichuan, and provide a reference for disaster prevention and mitigation.

Xietongmen County is located in the alpine mountain area of the Qinghai-Tibet Plateau, where the Kaga hot spring occurs. Geothermal energy is expected to be developed to solve the local heating problem, but research on the genesis and reserves of geothermal energy has not been carried out. By analyzing the geological structure and geothermal activity law of the survey area, and carrying out detailed geological survey, audio frequency magnetotelluric sounding and soil radon measurement near the Kaga hot spring, this paper discusses the genesis and thermal reservoir characteristics of ths Kaga hot spring by comprehensively using geological and geophysical exploration data. The research results show that (1) the audio frequency magnetotelluric and soil radon measurement results clearly reveal the extension and superposition relationship of the deep NE, NW and SN trending faults in the area, indicating that the area has a good permeable channel and thermal storage space. (2) The heat source in the study area is composed of the middle and shallow Eocene Oligocene magmatic rock decay exothermic heat source and the deep high-temperature magmatic melting heat source. The fracture zone is not only a deep thermal reservoir, but also a channel for the upwelling of deep hot water. The alluvial proluvial and other accumulative layers in the upper part of the Quaternary system are good caprocks of geothermal water, while the unconsolidated sediments in the lower part of the Quaternary system and some bedrock weathering crusts constitute shallow geothermal reservoirs in the area. These indicate that the geothermal application potential in this area is large, but it should be noted that, according to the three-dimensional display of audio frequency magnetotelluric sounding results, it is found that the deep S1 and S2 abnormal areas are connected at the shallow part, and the surface hot spring vent is just above its connecting channel, so the impact of the water volume of this hot spring vent needs to be evaluated when drilling water nearby. Finally, combined with the geothermal characteristics and electrical characteristics of geothermal water in this area, the “geophysical geothermal geology” model of the survey area is constructed, providing reference and guidance for the exploration and development of geothermal resources in other regions of Tibet.

The Baiquan Spring in Xinxiang has many functions, such as water supply, agricultural irrigation, humanities, tourism and ecology. It is of great significance to study the dynamics of the spring flow rate and establish a dynamic prediction model for the spring water resources evaluation and protection. In order to further study the dynamic characteristics of the Baiquan Spring flow rate in Xinxiang and evaluate karst water resources in the spring area, based on the data of annually measured spring flow rate and annual average precipitation in the spring area from 1964 to 1978, the main influencing factors of the spring flow rate are determined by using the stepwise regression analysis, and a stepwise regression model is established, with remarkable regression effect. On the basis of the stepwise regression analysis, this paper establishes the GM(1, 2) model, NSGM(1, 2) model and GM(0, 2) model for the dynamic prediction of the spring flow rate. The results show that (1) from 1964 to 1978, the Baiquan spring flow rate was mainly controlled by the precipitation in the spring area, and the spring flow rate lagged behind the precipitation for one year, reflecting the dynamic characteristics of the spring water in the natural state. (2) The accuracy levels of the three grey models are the highest (excellent). (3) From 1964 to 1978, the measured discharge of the Baiquan spring ranged from 2.347 to 6.448 m3/s, with an average of 3.904 m3/s. The predicted values of the stepwise regression model range from 1.882 to 6.383 m3/s, with an average of 3.904 m3/s. The predicted value of the GM(1, 2) model varies between 2.327 and 6.448 m3/s, with an average of 3.939 m3/s. The predicted values of the NSGM(1, 2) model range from 2.133 to 6.448 m3/s, with an average of 3.927 m3/s. The predicted values of the GM(0, 2) model range from 1.787 to 6.448 m3/s, with an average of 3.907 m3/s. (4) The average relative errors of the stepwise regression model and the three grey models mentioned above are 7.794%, 7.292%, 7.122% and 7.797% respectively, all of which are less than 10%, indicating that they can be used for dynamic prediction of the spring water. Among them, the NSGM(1, 2) model has a higher accuracy and better fitting to the inflection point of the curve. (5) According to the spring flow rate from 1964 to 2030 predicted by the four models, the exploitation resources of the karst water in the Baiquan spring area should not exceed 1.69 m3/s from the angle of spring protection. The research results can not only provide scientific basis for spring flow dynamic prediction and spring area water resources evaluation, but also provide reference for the study of groundwater dynamics in similar areas.