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Rapid flow-like landslides frequently occur in mountainous regions. To mitigate the disasters caused by these landslides, it is crucial to develop robust numerical models that can accurately predict their run-out processes. Models based on the material point method (MPM) offer significant advantages in simulating large deformation issues in geomaterials, including landslides. However, applying these models to accurately simulate real-world rapid flow-like landslides remains a challenge, primarily due to the complexities involved in handling the three-dimensional (3D) sliding bed boundary. This paper introduces a novel 3D MPM model specifically designed for simulating rapid flow-like landslides that propagate across curved beds. The constraints of the sliding bed on the landslide are imposed by the boundary nodes close to the bed. These boundary nodes carry information about the normal vector of the sliding bed, derived directly from the digital terrain model (DTM). Furthermore, the model integrates a hybrid formulation that combines the Full Lagrangian Implicit Particle (FLIP) method with the Particle In Cell (PIC) method, facilitating a stable solution for the velocity and position of material points. The effectiveness of the proposed model is confirmed through a numerical analysis of a rigid block sliding down an inclined plane and an experiment of sand flow on a curved bed. The simulation results from these two benchmark scenarios align closely with both analytical and experimental data, attesting to the validity of the model. The model is then applied to analyze a rapid flow-like landslide that occurred in Gansu Province, China, characterized by a curved sliding bed. The outcomes illustrate the model's capability to efficiently capture the landslide's climbing and turning motions induced by the meandering topography. Moreover, it successfully reproduces the main deposition characteristics observed in the field, demonstrating the model's strong suitability for simulating the propagation of rapid flow-like landslides on naturally curved beds. [ABSTRACT FROM AUTHOR]

To ensure viability, it is necessary for an intertwined supply network (ISN) system to optimise network structure to provide flexible redundancy in response to changing environment. Considering resilience methods are usually designed as reactions to single discrete disruptions rather than situational reactions to real-time changes, this study proposes a novel redundancy optimisation approach dynamically providing each demand market with a pair of supply routes to optimise the flexible redundancy of ISN, thereby ensuring the survivability of supply chains and demand markets under continuous changes. Based on this, we propose the ISN design (ISND) model to capture the trade-off between total cost and viability performance under facility and transportation disruption. The Lagrangian relaxation algorithm, combined with the sub-gradient method and the improved cellular genetic algorithm, are utilised for solving problems of different scales. To test the performance of the model and corresponding algorithms, we also conduct a numerical analysis of the data from medical equipment ISN in southern China. The results indicate that the ISND model can effectively optimise ISN structures, which makes it possible to dynamically provide flexible redundancy; the two algorithms also show good calculation efficiency. The relationship between ISN structure and viability performance is thus observed and explained. [ABSTRACT FROM AUTHOR]

Double-story high-speed railway stations have become increasingly popular due to their smaller footprint and improved operational efficiency. However, ensuring passenger comfort in such stations requires careful consideration of train-induced vibrations. This study investigates the train-induced vibrations in Beijing Fengtai Railway Station, which is Asia's largest and China's first double-story high-speed railway station. To carry out this work, a vibration source load model and the finite-element model of the station were first established, where the model was verified using field-measured data. Following these, the vibration characteristics of the station under various train passing conditions, including different track positions and train speeds, were investigated numerically in both time and frequency domains. The findings of this study provide valuable insights for the vibration control of the railway stations of the similar modes and scales. [ABSTRACT FROM AUTHOR]

In geotechnical engineering, a bedding slope often leads to geological disasters, particularly in the case of bedding-locked rock slopes. This study focuses on a typical bedding-locked rock slope in western Henan Province, China. The deformation and fault characteristics were examined through the development of laboratory analogue experiments which allowed for the analysis of the physical and mechanical properties of the rock slope when subjected to a load. The deformation and faulting mechanisms of the slope were studied through the application of different strength loads to the slope model, as well as through the combination of its physical properties. The deformation and fault process were then simulated through the application of numerical modeling. The results reveal that the upper part of the slope features a linear slip surface, while the lower part features a circular arc slip surface, resulting in "linear + circular arc" damage geometry and a relatively flat shear surface. Maximum and minimum lateral displacement occur around the top and the foot of the slope, respectively, leaving the intermediate values at the middle. The shear strength is greater at the locking section, with the highest value found at the foot of the slope, followed by the middle and the top. The evolution of slope deformation can be divided into three stages: the loose deformation stage at the slope top and back; the stage of crack development, extension, and interlayer misalignment; and the stage of complete through crack formation and complete instability damage of the slope. Thus, the process of the deformation and damage of a rocky slope under loading conditions can be described as follows: load-induced loosening and deformation at the top and back of the slope, crack development, expansion, and interlayer misalignment, as well as tension crack expansion at the foot of the slope. The latter can expand and intensify interlayer misalignment, leading to the destruction of the locking section and ultimately causing the destabilization of the entire slope. [ABSTRACT FROM AUTHOR]

Tight conglomerate rocks consist of gravels and rock matrices. The existence of these stiff gravels leads to heterogeneity in conglomerates and makes it difficult to characterize rock mechanical properties, which then affects drilling and hydraulic fracturing operations in tight conglomerate hydrocarbon-bearing reservoirs. This case study introduces a series of experimental and numerical analyses for the better understanding of rock deformation and elastic wave propagation patterns in a tight conglomerate reservoir in Junggar Basin, China. Tri-axial compression tests, acoustic test, and finite element modeling of rock deformation and elastic wave propagation in conglomerate rocks are presented. Experimentally tested samples exhibit good brittleness and shearing failure patterns, while well correlated static-dynamic elastic moduli and P-S wave velocities are captured. Numerical results show that the existence of stiff gravels leads to strong direction-dependent stress and strain anisotropies. Stress concentrations are also induced by gravels radially and axially. In the elastic wave domain, stiff gravels facilitate the propagation of elastic waves. The gravel close to the wave source also induces stronger compressive/tensile states in the wave domain, indicating that the existence of gravels in conglomerates can alter waveforms. This integrated approach improves the quantitative understanding of stress, strain, and elastic wave responses in heterogeneous tight conglomerates. This case study also serves as a reference for the brittleness evaluation and geomechanical evaluation in the study area. The contribution of this work is primarily about the integrated experimental study, solid deformation modeling, and elastic wave modeling of tight conglomerate rocks. [ABSTRACT FROM AUTHOR]

Large-span spatial structures, with good appearance and plasticity are mostly used nowadays in urban landmarks. During the construction process, the loads are accumulated along with the construction conditions and the responses vary from the construction paths. Hence, a safety evaluation or monitoring of the construction process appears significant. During monitoring, the installation moment of strain gauges is not always the ideally non-loading status, the absolute or real strains in the structural components are difficult to acquire. Furthermore, the displacement monitoring for all key points reduces the construction efficiency. Herein, a response-increment real-time comparison strategy of stresses and unloading point displacements within numerical analysis is announced to avoid the above shortcomings. Based on a real large-span truss structure located in China, four construction schemes are proposed and investigated by simulation method. With the proposed construction scheme and monitoring strategy, a stress and displacement monitoring for the large-span truss structure was conducted. Through the comparison between the monitoring and simulation data, the proposed strategy is verified feasible for the construction monitoring, the efficiency is accelerated and the safety is guaranteed. [ABSTRACT FROM AUTHOR]

Coalbed methane extraction not only reduces natural emissions of a greenhouse gas, it also allows for safer coal mining and reduces the risk of underground disasters. The pressure environment of coal is an important factor in the gas extraction effect, so it is important to accurately assess the pressure distribution in front of the working face. In this paper, we analyzed the pressure distribution of the coal mass in front of the working face by means of numerical simulations. We then proposed the concept of self-relief pressure zone based on the numerical simulation results to accurately determine the efficient gas extraction area. Finally, a field test was conducted in the Qinshui Basin of Shanxi Province, China. Numerical simulations indicated that there is a self-pressure relief zone of about 4.86 m to 5.06 m in front of the working face. The total stress of coal seam in self-relief pressure zone is obviously small, showing obvious plastic deformation characteristics. Field tests showed poor methane extraction when the borehole was in a stress concentration zone. The amount of pure methane extracted significantly increases when the borehole enters the self-relief pressure zone in front of the working face. For the test working face, the width of the pressure relief zone in front of the working face is about 8.9 m to 14.7 m. Furthermore, we analyze the mechanism of the effect of self-relief zones on gas extraction and discuss how self-relief zones can be used to improve gas extraction in coal seams. Thus, these findings have important theoretical foundations for the field application of gas extraction with pressure relief in coal mines. [ABSTRACT FROM AUTHOR]

Mountain Excavation and City Construction (MECC) represents a prominent anthropogenic endeavor aimed at facilitating urban expansion in the Loess Plateau of China. It is important to comprehend the long-term settlement behavior at MECC engineering sites to effectively assess the project's success in reshaping landscapes and expanding urban areas. In this study, a typical MECC project, specifically the upstream area of the Liujiagou Valley within the new district of Yan'an City, is selected as a case study to investigate long-term settlement characteristics. The research involved conducting creep tests on soil samples with varying dry densities and moisture content and continuous in-situ monitoring of ground surface settlement at 17 specific points. Furthermore, a numerical model was developed and calibrated using the in-situ monitoring data to predict the long-term settlement. The findings reveal that an increase in soil dry density and a decrease in soil water content contribute to reduced deformation. Notably, settlement primarily manifests within the filled areas, with greater soil thickness exacerbating settlement effects. Over time, cumulative settlement exhibits a progressively diminishing rate of deformation until it attains a stable state. These results provide insights for assessing the long-term stability of MECC projects, facilitating decision-making in future endeavors within this region. [ABSTRACT FROM AUTHOR]

An increasing number of field investigations have revealed that the transverse cracks in semirigid asphalt pavement are more likely to initiate in the top of the asphalt layer rather than in the bottom of the asphalt layer, which conflicts with the widely accepted view that bottom-initiated reflective cracking is the dominant distress. To analyze the initiation cause of this kind of surface crack, a numerical simulation model coupled with multiphysics fields was built. It was based on the viscoelastic-plastic damage model, using the finite-element software Abaqus to calculate the damage distribution coupled with the temperature field as well as the loading field. The simulation results show that asphalt layers have two main damage regions in the semirigid base crack section, located in the top asphalt layer and the bottom asphalt layer. The increase of asphalt layer thickness and the decrease of heavy loads are the most possible causes of surface-initiated cracks replacing reflective cracks in semirigid pavements in recent years in China. [ABSTRACT FROM AUTHOR]

Shale oil represents a relatively new form of unconventional oil and gas resource, and the extensive exploration and development of shale oil resources carry significant implications for China's oil and gas supply and demand dynamics. At present, within the realm of low-maturity shale oil extraction technologies, the reservoir must be subjected to elevated temperatures ranging between 400 to 60 °C. Prolonged exposure of wellbores to such high temperatures can result in a substantial decrease in cement strength, the formation of microcracks due to cement cracking, and damage stemming from thermal stresses on the casing. Casing damage stands out as a prominent factor contributing to wellbore integrity failures and well shutdowns within the context of shale oil development. Given the limited natural energy reservoirs of shale oil formations, it becomes necessary to supplement the reservoir's energy during the development process. Furthermore, shale oil exhibits high viscosity and poor flowability, and conventional water injection methods yield limited efficacy. This situation can induce significant shifts in the stress field and rock mechanical parameters, potentially activating specific formations and complicating the load dynamics on the casing. Consequently, the risk of failure increases. In light of these considerations, this study uses numerical simulations to study the integrity of high-temperature injection and production wellbores in shale oil and aims to encompass a comprehensive evaluation and analysis of the principal factors that influence casing damage, the fluctuations in thermal stress, and the yield strength of various steel grades of casings exposed to alternating stress conditions. Subsequently, this paper developed a model for simulating the temperature and pressure within shale oil and steam injection wellbores to support engineering design analysis. The research results indicate that the application of pre-stress results in a significant increase in stress at the casing pipe head while causing a noticeable decrease in stress within the pipe wall. When N80 casing is used, the entire casing experiences thermal stresses surpassing the casing's yield limit. Stress concentration may arise at both ends of the external seal, potentially leading to casing contraction, shear failure, and, under non-uniform stress conditions, casing bending deformation. The temperature of steam injection significantly influences the temperature field of the casing wall, with stress values experiencing a marked reduction when the steam injection temperature decreases from 350 °C to 200 °C, underscoring the substantial impact of temperature on casing thermal stress. As the steam injection process advances along with injection-production cycles, shear stresses at the interface can exceed the bond strength, resulting in relative slippage between the cement and the casing. The bonding force between the wellbore and the cement primarily depends on the interface's friction, particularly in the context of friction during wellhead lifting. This study endeavors to determine rational injection and production parameters under varying conditions, optimize completion methods, reduce casing damage, and extend the casing's operational life; it aims to offer critical technical support for the safe and efficient development of shale oil resources. [ABSTRACT FROM AUTHOR]

Purpose: The induction of geological disasters is predominantly influenced by the dynamic evolution of the stress and plastic zones of the multilayer rock formations surrounding deep-rock roadways, and the behaviours and mechanisms of high in situ stress are key scientific issues related to deep-resource exploitation. The stress environment of deep resources is more complex owing to the influence of several geological factors, such as tectonic movements and landforms. Therefore, in practical engineering, the in situ stress field is in a complex anisotropic three-dimensional state, which may change the deformation and failure law of the surrounding rock. The purpose of this study is to investigate the tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses. Design/methodology/approach: Based on data from the Yangquan Coal Mine, China, a finite difference model was established, and the elastic-plastic constitutive model and element deletion technology designed in the study were analysed. Gradual tunnelling along the roof and floor of the coal seam was used in the model, which predicted the impact tendency, and compared the results with the impact tendency report to verify the validity of the model. The evolutions of the stress field and plastic zone of the coal roadway in different stress fields were studied by modifying the maximum horizontal in situ stress, minimum horizontal in situ stress and lateral pressure coefficient. Findings: The results shown that the in situ stress influenced the stress distribution and plastic zone of the surrounding rock. With an increase in the minimum horizontal in situ stress, the vertical in situ stress release area of the roof surrounding rock slowly decreased; the area of vertical in situ stress concentration area of the deep surrounding rock on roadway sides decreased, increased and decreased by turn; the area of roof now-shear failure area first increased and then decreased. With an increase in the lateral pressure coefficient, the area of the horizontal in situ stress release area of the surrounding rock increased; the area of vertical in situ stress release area of the roof and floor surrounding rock first decreased and then increased; the area of deep stress concentration area of roadway sides decreased; and the plastic area of the surrounding rock and the area of now-shear failure first decreased and then increased. Originality/value: The results obtained in this study are based on actual cases and reveal the evolution law of the disturbing stress and plastic zone of multilayer surrounding rock caused by three-dimensional in situ stress during the excavation of deep rock roadways, which can provide a practical reference for the extraction of deep resources. [ABSTRACT FROM AUTHOR]

Rapid delivery of emergency supplies is of vital importance in disaster relief, and innovative means of delivery has been actively explored. Recently, a novel delivery approach that takes advantage of both trucks and drones is emerging in the commercial field. This synchronized truck-drone delivery (STDD) mode can benefit from the large capacity of trucks as well as the speed and flexibility of drones, which makes it promising for sending ungently-needed supplies to disaster-stricken sites, especially the areas severely damaged and thus inaccessible by trucks. This paper attempts to optimize the synchronized truck-drone paths for quick responses in disaster relief, when accounting for the priority of different disaster-stricken sites. We propose an integer programming model and develop exact algorithm to solve small-scale problems. For large-scale problems, we propose an algorithm based on dynamic programming. We verify that the STDD mode is more efficient than truck-only delivery. Further numerical analysis suggests that a drone with higher speed and longer endurance is not always the best choice. The efficiency of rescue efforts relies on careful calibration of the speed ratio of the drone to the truck and the maximum flight distance of the drone. Finally, the application of the model is illustrated by a case study of the 2008 earthquake at Wenchuan County in Sichuan Province of China. [ABSTRACT FROM AUTHOR]

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• The influences of the geometric parameters of the reactor on the SCPP-HPCR are investigated. • A formula is proposed to calculate the CO 2 emissions reduction of the system. • The optimal operating conditions of the SCPP-HPCR is analyzed. • 2.38 kg of CH 4 is degraded and 375.52 kg of CO 2 is reduced through the system one day. The increase of 1.09 °C in global temperature resulted in significant catastrophes because of the extreme climate. The climate change rate can be slowed down by reducing the levels of CH 4 and CO 2 in the atmosphere. The solar chimney power plant integrated with a honeycomb photocatalytic reactor (SCPP-HPCR) uses the photocatalytic technology to remove atmospheric CH 4. In addition, CO 2 emissions can be reduced from coal fired power plant due to the generating capacity of the system. In this paper, the influence of the geometric parameters of the reactor and turbine on the overall performance of the SCPP-HPCR is studied by numerical simulation. The obtained results showed that the flow resistance inside the system was mostly caused by the HPCR at low turbine speed, and primarily by the turbine at high turbine speed. Reducing the pore diameter of the reactor could improve the photocatalytic performance of the SCPP-HPCR more than increasing the turbine speed. The SCPP-HPCR having a pore diameter of 3 mm, porosity of 0.85, and constant turbine speed of 180 rpm, built in Qianyanzhou, China, could remove 2.38 kg of CH 4 and reduce 375.52 kg of CO 2 in one day. [ABSTRACT FROM AUTHOR]

High-speed railways often run over underground metro stations. Dynamic load induced by high-speed train can influence the internal force of underground structure and hence can pose danger to the underground structure. Hence, it is necessary to estimate the safety of underground structure due to high-speed train load. In this paper, the effects of dynamic load induced by high-speed train on metro station are investigated by carrying out three-dimensional numerical analysis. Guinan high-speed railway, which is designed to run over Jinqiao metro station in Nanning, Guangxi province of China are adopted as the background of this case study. The hardening soil model with small-strain stiffness was adopted to model the behaviour of soil. Two typical speed of railway train (i.e., 160 km/h and 350 km/h) are considered in this study. Based on the numerical analysis, vertical vibration acceleration and bending moment of the structure of the metro station are presented and analysed. [ABSTRACT FROM AUTHOR]

We consider a bottleneck system in a state of disequilibrium, in which commuters are heterogeneous in the values of travel time and schedule delays. Three representative dynamical systems are used to formulate the day-to-day departure time choice of commuters, and a Walrasian toll charge scheme is utilized to control the evolutionary process of traffic flows. The toll charge scheme is anonymous; that is, toll charges are identical for all user classes, and the scheme's implementation does not need to resort to information on the values of travel time and schedule delays. We find that the system optimum (SO) flow pattern can be achieved at the stationary state under the implementation of the toll charge scheme. The equivalence between the stationary state and the SO, the existence of the toll charge for achieving the SO, and the convergence of day-to-day traffic flows to the SO under the implementation of the toll charge scheme are theoretically proved. The distributions of traffic flows and toll charges at the SO state during morning rush hour are analytically shown. The application of the toll charge scheme to a network with multiple trip origins is presented. The effectiveness of the toll charge scheme for achieving the SO is also examined by numerical analyses. Funding: This work was supported by the National Natural Science Foundation of China [Grants 72171007, 71890972/71890970, and 72021001]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2022.1191. [ABSTRACT FROM AUTHOR]

Here, we report our recent progress in the design, fluid thermodynamics simulation, and high-power test of the2nd harmonic cavity for the China Spallation Neutron Source Phase II. A high-performance and large-size magnetic alloy (MA) core was developed as the load material for the radiofrequency cavity to achieve a high gradient of 40 kV/m. The water-cooling structure and cooling efficiency were studied and improved through numerical analysis and thermal experiments. The long-term stability of the cavity, especially the waterproofness of the MA cores with high heat load, was verified by high power tests. [ABSTRACT FROM AUTHOR]

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The lack of diagnostic taxonomic characteristics in some species complexes leave the species delimitation of Oxytropis DC. unresolved. Seed morphological features have proved to be useful diagnostic and taxonomic characteristics in Fabaceae. However, there are few systematic studies on the seed characteristics of Oxytropis. Here, we used scanning electron and stereoscopic microscopy to investigate the seed characteristics of 35 samples obtained from 21 Oxytropis species from northwest China. Our examination showed two main types of hilum positions, terminal and central, and five different types of seed shapes: prolonged semielliptic, reniform, prolonged reniform, quadratic, and cardiform. Seven different sculpturing patterns were identified: scaled, regulated, lophate with stellated testa cells, simple reticulate, rough, compound reticulate, and lophate with rounded testa cells. The seeds ranged from 1.27 to 2.57 mm in length and from 1.18 to 2.02 mm in width, and the length-to-width ratio ranged from 0.89 to 1.55 mm. The seed shape was constant within species and was useful for species delimitation within the genus Oxytropis when combined with other macroscopic traits. In contrast, the sculpturing patterns were highly variable at the species level and could not be used for species identification. Results of the cluster analysis and principal component analysis (PCA) indicated that the seed traits of Oxytropis species are useful for taxa identification at the species level, but have low taxonomic value at the section level. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To analyze the relationship between ground motion and different soil depth and effectively reduce the damage degree of ground motion, the amplification effect and law of soil depth on ground motion are studied. First, taking the earthquake area as the research object, drew the site distribution map of the earthquake area, modified the drilling site in the earthquake area by using the engineering drilling data, calculated the hysteretic coherence function of the site amplification system according to the random vibration theory, draw the number of site amplification systems and the PGA distribution map of the earthquake area, and complete the research on the effect of soil site depth on the ground motion amplification effect. By collecting ground motion monitoring data and investigating typical post-earthquake landslides and collapses, the characteristics of ground motion parameters, dynamic response characteristics of slope and dynamic parameter variation characteristics of aftershocks on slope are studied using statistical analysis, qualitative description, semi quantitative analysis and numerical simulation. The influence law of ground motion on the depth of coating site is analyzed to reduce the damage degree of ground motion. The test results show that this method can effectively analyze the influence of the depth of the coating site on ground motion, reduce the damage degree of ground motion, promote the construction of strong earthquake loss assessment system, enhance the practical application effect, improve the current situation of strong earthquake observation in China, determine the construction of strength, express loss assessment system, and improve the response speed and reliability of strength express loss assessment. It provides reference value for post-earthquake loss assessment. [ABSTRACT FROM AUTHOR]

A landslide located in northern Sichuan Province, China was investigated. A series of numerical models of the landslide stabilized with piles and anchor cable frame beams were developed using a three-dimensional finite-element method. The Strength Reduction Method was employed to investigate the stability of slopes, the internal forces of piles, and the axial forces of anchor cables. A parametric study consisting of pile position, pile length, and pile spacing was carried out. The results show that compared to anchor cable frame beams, the combination of piles and anchor cable frame beams is a more effective retaining structure to improve slope stability. During slope destabilization, the proportion of thrust shared by piles gradually increases, while the proportion of thrust shared by anchor cables gradually decreases. Piles installed on the leading edge of a trail-mode landslide can make the slope mostly stable. As the piles move from the leading, middle, and trailing edges of the slope, the proportion of thrust shared by the anchor cables gradually increases, while local instability may occur in front of the pile. Increasing the pile length can improve the stability of the slope. However, excessive embedded length of piles has little effect on further improving the slope stability. The critical embedment length of piles found in this study is 1/3 of the total length of the pile. The critical pile spacing found in this study is 2.5 times the width of the pile section. Beyond this spacing, the effective soil arch between the piles is difficult to develop and the anchor cables may share more proportion of the landslide thrust. This study provides a reference for reinforcement system design of engineering projects considering piles and anchor cable frame beams. [ABSTRACT FROM AUTHOR]

Objectives: For the traditional conformal conic projection, Newton 's iterative method is generally used to solve the reference latitude. However, the method requires to be iterated repeatedly, which leads to relatively low computational efficiency and is not easy to be extended and utilized. Therefore, non-iterative expressions for the reference latitudes B0，B1，B2 of the spherical conformal conic projection are derived in this paper to facilitate theoretical analysis and numerical computation. Methods: In order to simplify the fussy iterative algorithm in calculating the reference latitude of the traditional conformal conic projection, the average latitude and the average latitude difference were introduced. With the help of the powerful computer algebra system Mathematica, the non-iterative algorithm of the conformal conic projection based on the sphere model is proposed. Compared with the traditional ellipsoid iterative algorithm, the country and provinces with different latitude differences are taken as examples. Results: Numerical examples show that the maximum relative error of the reference latitudes B0，B1，B2 calculated by the non-iterative formula of the sphere model derived is less than 2.011% and the relative error of length deformation is less than 1 × 10-6. For provinces with different latitude differences, the smaller the latitude difference, the closer the reference latitude calculated based on the sphere model to that based on the ellipsoid model, the smaller the relative error of length, and the closer the length deformation. Conclusions: The derived non-iterative expressions overcome the tedious iterative process and make the theoretical analysis more convenient, which enriches the map projection theory to a certain extent. The established mathematical model can be extended to the non-iterative algorithm for solving the reference latitude for rectifying and authalic conic projection under the sphere model and each conic projection under the ellipsoidal model, and the algorithm is applicable to the whole map of China and all provinces. Therefore, the non-iterative algorithm of spherical conic projection derived can be used to replace the traditional complex iterative algorithm in the process of making small and medium scale maps in China. [ABSTRACT FROM AUTHOR]

2E12 is a new aluminum alloy material made in China. It is to be used in aircraft fuselage skin structure. Damage tolerance performance is one of its key indicators for the material. According to the requirement of damage tolerance design, this paper designs three typical test pieces of fuselage panel structure, including single-span crack, double-span crack and crack repair. Firstly, the numerical analysis of crack propagation and residual strength is completed, and then the verification test is carried out. The results are compared with those of 2024 aluminum alloy. The results show that the damage tolerance of 2E12 aluminum alloy material can meet the design requirements. Compared with single crack propagation, the existence of multi-crack increases the crack growth rate significantly, and the total life of multi-cracks is shortened by about 30%. The error of crack propagation analysis and test results is less than 10%. The residual strengths of all test pieces are in good agreement, and the difference between the analytical results and the experimental results is about 2.3%. [ABSTRACT FROM AUTHOR]

Karst landforms constitute one of the most harmful geological conditions, which have an adverse effect on the deep foundation structures of bridges. During earthquakes, the existence of karst caves can cause serious seismic damage to the bridge pile foundation. In order to investigate the seismic response of rock-socketed piles under vertical loads in complex karst cave conditions, finite element numerical simulation analyses were carried out, referring to the practical major bridge structure rock-socketed pile project in China. The peak strain distributions of rock-socketed pile foundation influenced by single-karst cave factors under the combined action of vertical loads and ground motions were investigated, and the influences of complex multi-caves were further explored. The results showed that the restraint effect of the bedrock near the pile would gradually decrease with the increase of the height of the karst cave and the decrease of the height of the karst cave roof; under the condition of a beaded karst cave, the constraint of bedrock between the karst caves makes the pile present the distribution characteristics of "multi-segment and multi-broken line"; under the condition of an underlying karst cave, the existence of the underlying karst cave would decrease the restraint of the bedrock at the bottom pile and increase the peak strain of the pile to a certain extent. This paper revealed the seismic response law of the rock-socketed pile under vertical loads within various complex karst cave conditions and developed reasonable reinforcement measures aiming at dangerous locations, providing important engineering guidance and a reference for the seismic design of rock-socketed pile foundation in complex karst areas. [ABSTRACT FROM AUTHOR]

The development of underground space is fast because of the lack of space. To build shafts in underwater tunnels, the vertical tunneling method (VTM) was invented in 1974 in China, which can act as a freshwater intake or sewage outlet. During the operation of the VTM, the jacking force is one of the essential factors that draw attention. This paper conducts a numerical study of the jacking force and its influencing factors during the vertical tunneling process. First, based on the finite element software ABAQUS, a numerical model of the vertical tunneling process is established according to the VTM project in Beihai, China. Second, in accordance with the Latin hypercube sampling method and the multivariate significance analysis, the mechanical parameters are determined or back-analyzed. Then, the calculated jacking force of the numerical model is compared with the measured jacking force. It turns out that the changing trend of the jacking force in the numerical model and the measured jacking force is relatively consistent. Finally, the influencing factors of the jacking force, such as elastic modulus and the angle of internal friction, are analyzed based on the numerical model. The results show that the elastic modulus and the angle of internal friction of soil are the main influencing factors of the jacking force. The secondary factors are Poisson's ratio, static earth pressure coefficient, unit weight, and cohesion. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mechanism of the impact of inter-firm social networks on innovation capabilities has attracted much research from both theoretical and empirical perspectives. However, as a special emerged and developing complex production system, how the scenario factors affect the relationship between these variables has not yet been analyzed. This study identified several scenario factors which can affect the firm's technological innovation capabilities. Take the manufacturing scenario in China as an example, combined with the need for firms' ambidexterity innovation and green innovation capability, a multi-objective simulation model is constructed. Past empirical analysis results on the relationship between inter-firm social network factors and innovation capabilities are used in the model. In addition, a numerical analysis was conducted using data from the Chinese auto manufacturing industry. The results of the simulation model led to several optimization strategies for firms that are in a dilemma of development in the manufacturing scenario. [ABSTRACT FROM AUTHOR]

Wildfires are becoming a global natural disaster under climate change. A worthwhile concern is that the rainfall thresholds that trigger debris flows in catchments affected by recent wildfires are much lower than those that trigger debris flows in catchments with similar environments but that have not experienced wildfires. In this study, we investigated a major post‐fire debris flow event in Xiangjiao catchment triggered by heavy rainfall in 2021. Through the combination of field observation, laboratory experiments and several numerical models (rainfall interception, infiltration, erosion and runoff models), the physical mechanistic analysis and numerical simulation of the post‐fire debris flow in Xiangjiao catchment was carried out. Results show that the simulated deposited area, erosion depth, and the occurrence time of debris‐flow initiation correlate well with the actual situation. It is demonstrated that the numerical simulation method used in this study can be used to effectively describe the characteristics of the initial and propagation stages of the post‐fire debris flow generated by runoff and provide important insights and guidance for the prediction and prevention of debris‐flow disasters in catchments affected by wildfire. Plain Language Summary: Wildfires are becoming more and more common under more frequent extreme weather. After the wildfire, the overall environment would be substantially changed, which will lead to more frequent debris‐flow disasters. Consequences of these changes are worthy to be deeply investigated. In this study, we investigated a major 2021 post‐fire debris flow event in Xiangjiao catchment, China, triggered by heavy rainfall. Through the combination of field observation, laboratory experiments, and numerical models, the physical mechanistic analysis and numerical simulation of the post‐fire debris flow in Xiangjiao catchment was carried out. Key Points: The mechanism of post‐fire debris flows caused by runoff in Xiangjiao catchment is analyzedUsing multiple numerical models and multi‐source data, the 2021 Xiangjiao post‐fire debris flow is simulatedThe numerical simulation results are analyzed and correlated well with the field investigation [ABSTRACT FROM AUTHOR]

An analytical method for determining the stresses and deformations of landfills contained by retaining walls is proposed in this paper. In the proposedmethod, the sliding resisting normal and tangential stresses of the retaining wall and the stress field of the sliding body are obtained considering the differential stress equilibrium equations, boundary conditions, and macroscopic forces and moments applied to the system, assuming continuous stresses at the interface between the sliding body and the retaining wall. The solutions to determine stresses and deformations of landfills contained by retaining walls are obtained using the Duncan-Chang and Hooke constitutive models. A case study of a landfill in the Hubei Province in China is used to validate the proposed method. The theoretical stress results for a slope with a retaining wall are compared with FEMresults, and the proposed theoreticalmethod is found appropriate for calculating the stress field of a slope with a retaining wall. [ABSTRACT FROM AUTHOR]

Seasonally frozen soil regions refer to those areas where soil is frozen for 15 days or more per year. More than half of land surface is occupied with the seasonal snow cover in China. The freeze-thaw process can significantly change the soil properties, as well as the water and heat transferring in the vadose zone. Among them, temperature and water vapor have posed a significant impact on the soil moisture, due to the soil subjected to the dry condition in most of the seasonally frozen regions (belonging to the arid and semi-arid areas). It is gradually recognized as the significant effect of vapor flow on the soil water movement for both freezing and non-freezing periods over the past several decades. It is a high demand to couple the water, vapor, and heat transport suitable for the actual conditions of seasonally frozen soil regions, in order to reveal the influencing mechanism of soil hydrological cycle. The coupled theory of water, vapor, and heat transport was firstly proposed by Philip and de Vries. The total soil water flux was then divided into four components, including the liquid water flux and water vapor flux driven by water potential and temperature gradients, respectively. Since then, extensive researches were also carried out to continuously improve on the coupled transport. Once the soil was frozen, the liquid water, vapor, and ice were coexisted in the unsaturated zone. Two aspects were also observed in the influence of phase changes between liquid water and ice on the coupled water, vapor, and heat transport. Several hydraulic parameters were calculated to determine the hydrological cycle, such as the soil freezing curve, and hydraulic conductivity for the liquid water. The spatial and temporal distributions of soil moisture in the vadose zone were dominated by the seasonally freeze-thaw process as well. The contents of unfrozen water and ice also changed significantly with the variations of soil temperature. Numerical simulation was gradually utilized in this research field with the ever-increasing computational capacity and simulation accuracy. Great challenges were still remained on the coupled numerical model, due to the influence from the ice-water phase change. An appropriate coupling model was crucial to the numerical simulation via the reasonable simplification. The underlying mechanism of coupled water and vapor flow was gradually revealed from the simulation using different models. Specifically, the vapor flux was one of the most important components in the soil water movement, usually accounting for 10%-30% of the total water flux. Furthermore, the vapor flux was depended mainly on the relatively low soil moisture and large temperature gradient in the shallow layer. The vapor flow was much more significant during the freezing period, due mainly to the impeded flow of liquid water in the presence of ice. Consequently, some research directions that needed to be strengthened in this field were proposed to deepen the theoretical fundamentals and the practical tasks in the seasonal frozen soil areas. Firstly, the condensation and accumulation of water vapor can greatly contribute to the vegetation under soil drought and freezing stress. It is of great significance to maintain the desert vegetation ecosystem, where the soil water is critical to the vegetation growth in the fragile ecological areas. The vegetation module can be combined with the coupled model water, vapor, and heat transferring. Further studies can be implemented to explore the specific impact of liquid water and vapor on the surface vegetation in seasonal frozen region. Secondly, the coupled transport of liquid water and vapor can also impact many engineering construction activities as well, such as the frost heave in the railway embankments that caused by the continuous liquid water and vapor transport from the deep soil layer. Finally, in-situ monitoring and simulation can be strengthened to reveal the detailed process of liquid and vapor transport below the surface impermeable layer. The finding can also provide the scientific basis for the disaster prevention and control during freeze-thaw process. [ABSTRACT FROM AUTHOR]

To solve these problems of poor supporting effect and serious deformation and failure of surrounding rock of mining roadway under deep mining stress, a FLAC-3D numerical calculation model is established with −800 m level no. 2424 upper roadway in the Suncun Coal Mine as the background to compare the stress, deformation, and failure law of surrounding rock of mining roadway under once support and multi-level support with the same support strength. It is found that the multi-level support technology has obvious advantages in the surrounding rock of the horizontal roadway on the 2424 working face. From this, the key parameters of multi-level support are determined, and the field industrial test is carried out. The results show that the overall deformation of the surrounding rock is obviously reduced after multi-level support. The displacement of the two sides is reduced by about 40%, the displacement of the roof and floor is reduced by about 30%, and the plastic zone of the roadway is reduced by about 75%. The peak value of concentrated stress decreases from 98.7 MPa to 95.8 MPa, which decreases slightly. The integrity and stability of the surrounding rock are excellent, and the support effect is satisfactory. The research can provide reference and technical support for surrounding rock control of deep high-stress mining roadways. [ABSTRACT FROM AUTHOR]

As the hydropower development strategies of China continue to be implemented, a host of large hydropower projects have been completed or are being constructed in southwest China. During construction of the Jinchuan hydropower station, this study examined the stability of the surrounding rock during the excavation and unloading of hydraulic tunnels under demanding geological conditions. Microseismic (MS) monitoring technology was employed to monitor the deformation and failure of the surrounding rock online and in real time, based on engineering geological data and site surveys. To analyze the stability of the surrounding rock in the spillway tunnel and to study the temporal and spatial evolution characteristics of MS events, source parameter analysis and numerical modeling were performed. The 3D finite-difference numerical modeling software FLAC3D was used to simulate the mechanical response of the surrounding rock during the excavation and unloading of the spillway tunnel and the diversion tunnel. The numerical modeling results were compared with the monitoring results and site surveys to determine the failure mechanisms of the surrounding rock during the construction and unloading of the hydraulic tunnels. The research results can serve as a guide for studying the stability of the surrounding rock in similar hydraulic tunnels. [ABSTRACT FROM AUTHOR]

Aiming to address the production potential and evaluation method of coal-bed methane (CBM) for low-rank coal, taking Coal Seam 4 of Dafosi mine field in Binchang mining area as the research object, the adsorption and desorption experiments, drainage numerical simulation and analysis of the gas production characteristics were carried out. The gas content, coal seam thickness and permeability, and other geological parameter combinations of CBM recoverability were determined. The numerical simulation results reveal that CBM has considerable production potential due to its large thickness and high permeability. Therefore, the geological control mechanism of CBM recoverability is strong desorption capacity, large coal-seam thickness and high reservoir permeability. Combined with the practical analysis, the gas content is the first factor to determine the recoverability. Moreover, the classification evaluation index is established, and the four-level classification index requirements for the optimisation are determined. Furthermore, the concept of CBM enrichment and the high-yield area is defined, and various geological indexes and conditions are specified. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most of the coal mines in Southwest China are located in mountainous areas with high vegetation coverage, and most activities are carried out under the mountains. The deformation monitoring and mechanical behavior analysis of the mining area helps reveal the typical mountain deformation and failure mechanism caused by underground mining activities and reduce the risk of mountain collapse in the mining area. In this manuscript, a research method for mountain stability in mining areas is proposed, which combines InSAR deformation monitoring with numerical analysis. Based on the high-precision deformation information obtained by DS-InSAR and the landslide range, a three-dimensional explicit finite difference numerical analysis method was used to reconstruct the landslide model. According to the layout of the coal mining working face, the variation mechanism of overlying stratum stress and the mountain slip in the coal mining process is inverted, and the mechanism of mountain failure and instability in the mining area is analysed. Based on the sentinel data, the experiment performed time series monitoring and inversion analysis of the mountain collapse in Nayong, Guizhou, China. The results show that mining activities a certain distance from the mountain will affect mountain stability, and there are specific mechanisms. From 2015 to 2017, the stress redistribution of overlying strata above the goaf area resulted in dense longitudinal cracks in the landslide body due to coal mining. The mountain is in a continuous damage state, and the supporting force to prevent collapse continues to decrease, resulting in a gradual decrease in landslide stability. Both the time series DS-InSAR monitoring results and numerical simulation results verify the actual occurrence and development of the on-site subsidence. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Currently, large-diameter monopile-supported offshore wind turbines (OWTs) are widely used in offshore areas of China. However, considerable numbers of wind farms are located in seismically active areas with liquefiable soil layers. Therefore, shaking table tests and numerical simulation based on a scaled model of Siemens SWT-4.0-130 OWTs were carried out to investigate the failure mechanism of the OWT system in liquefiable sand under combined wind, wave and seismic loads. The scaling law focusing on the governing physical mechanism of the OWT system considering multi-field coupling are presented and verified. The dynamic responses of the OWT and the excess pore pressure fluctuation around the soil-monopile domain in different operating states are discussed and compared. The results show that the proposed scaling laws can well restore the dynamic characteristics of the prototype. The seismic excitation is the dominant load for inducing the structural response under combined wind, wave and seismic loads. Due to the coupling effect, the dynamic responses under combined wind and wave loads were slightly less than the superposition of structural responses under separated wind or wave loads. Liquefaction of the shallow soil layer within the range of four times the pile diameter was detected when the PGA reached 0.4 g (three-dimensional input) or 0.64 g (one-dimensional input), which induced obvious tilt and settlement of the OWT model after the test. The sudden increase in the pore pressure resulted in the liquefaction of soil, which further led to a significant decrease in the natural frequencies and decay of the acceleration responses at the tower top. The above findings are expected to provide valuable experience for the 1 g underwater shaking table tests on OWT systems and insights for the practical design of OWTs in seismically active areas. • The scaling laws focusing on the governing mechanism of the OWT system are derived. • Shaking table tests are conducted to reveal the failure mechanism of the OWT system. • The influence of dynamic PSI and the coupling effect of dynamic loads are evaluated. [ABSTRACT FROM AUTHOR]

Considering the operation efficiency of the metro system, the boarding queuing problem is a complex and intractable dilemma caused by the security and ticket checking process in urban metro stations, especially for the mass-transit metro system in China. In this study, a novel scheme of fare differentials based on demand control and congestion management for reducing congestion in the metro boarding process was proposed. In addition, we extended Vickrey's point-queue model into a boarding congestion model incorporating the bidesired departure time considering the security and ticket checking process in stations as a continuum bottleneck. The train-run and departure time choosing behaviors of passengers under different schedule gaps of the adjacent train runs are explored when the boarding system achieves user equilibrium in the proposed model. Then, we examined the demand regulatory mechanisms of fare incentives (fare differentials) in reducing the queuing boarding time in metro stations when the optimization of the schedule gaps is ineffective in the pattern of mass-scale travel demand. The analytical solutions of these two optimal methods (schedule gaps and fare differentials) for boarding congestion management are presented. After comparing the two congestion-reduced methods, the fare incentive rule has a better regulation effect on the smoothing of travel demand. The results of the sensitivity analysis using numerical simulations reveal the regulatory mechanism of fare differentials in reducing the queuing time and increasing the incremental revenue. (1) The demand threshold is only related to the boarding capacity and schedule gaps (i.e., the greater the boarding capacity and schedule gaps, the greater the passenger capacity of the metro station). (2) The effect of fare incentives in reducing the boarding congestion is better if the lower fare is implemented in the later train runs. (3) A lower fare differential between two adjacent metro runs can be used to regulate the proportion of staggered passengers in the queuing line to reduce the crowd gathering in the metro station hall when travel demand is high, meanwhile, a higher fare differential between two adjacent metro shuttles can increase incremental revenue effectively. (4) The measure of fare differentials causes worse results in both the reduction of the queuing time and the increase of the incremental revenue when the metro travel demand is lower than the demand threshold. This conclusion is consistent with the pattern of reality and experience. Therefore, the definition and judgment conditions of demand thresholds, introduced in this study, can provide theoretical guidance when implementing fare incentive policies in aviation and metro networks. [ABSTRACT FROM AUTHOR]

The talus-like rock mass is a special kind of geomaterial widely distributed in southwestern China, which has induced serious engineering disasters for tunneling engineering. However, the mechanical behavior of the talus-like rock mass remains unclear as the previous studies mainly focused on similar geomaterials such as the soil–rock mixtures. In this paper, we have carried out both experimental and discrete element method (DEM)-based numerical analyses to investigate the shearing characteristics of the talus-like rock mass collected from a real project site. Large-scale direct shear tests reveal that the strength parameters increase with the block content, which is different from the traditional soil–rock mixture. A dependence has been discovered in that the specimen dilation becomes more obvious under lower normal stress and larger block content. It is also observed that higher normal stress is beneficial for crushing blocks. The force chains obtained in the DEM simulations show that distinct internal structures are generated in the rock samples with different block contents. The distribution of coordination number establishes the dependence of fabric stability on block content during shearing. Bond-break evolution reveals the tendencies of crushed particles were consistent with those of experimental tests. The findings provide a more in-depth understanding about the mechanical behavior of the talus-like rock mass, which helps to uncover the cause of the collapse of the real tunnel project. [ABSTRACT FROM AUTHOR]

This work systematically summarized four types of methods for predicting tunnelling induced ground movements, namely analytical solution, empirical equation, numerical simulation and model test method. The theory of four types of analytical solutions was firstly presented. The widely-used empirical equations and determination methods for the key parameters were introduced. The development of numerical analysis methods with respect to soil constitutive model and simulation technique was discussed. The 1g model test and centrifuge model test were presented in brief as well. Some suggestions on predicting tunnelling induced ground movements in China were presented according to the advantages and disadvantages of various methods. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rock resistivity is a major geophysical technical parameter in geological and geotechnical engineering, geothermal prospecting, and oil and gas exploration. Its accurate measurement is of great significance to achieve the goal of "carbon peak and carbon neutrality". To solve anisotropic problems, a method to test the radial resistivity in cylindrical core samples has been proposed and has been deemed the universal method, as it has the virtues of no specially processed sample being needed and nondestructive testing. However, there is still a difference in the radial resistivities obtained from this method and another testing method that is commonly used for cuboid samples. Furthermore, the differences between these methods have not yet been made clear in China or elsewhere. Therefore, we compared the results of the above-two testing methods via numerical simulations after establishing the potential field distribution, and, in combination with their methodological principles, illustrated the differences between the resistivities determined in samples with distinct shapes obtained using the two testing methods, summarized the conditions when there was zero difference and considerable difference when using the two methods, and provided a theoretical basis for the reasonable selection of an appropriate method to test the resistivity anisotropy. [ABSTRACT FROM AUTHOR]

On 5 April 2021, a high-position landslide occurred in Tiejiangwan, Liujiang Town of Hongya County, Sichuan Province, China. The detached mass transformed into a debris avalanche traveled about 1300 m with an elevation difference of 665 m and caused three fatalities. Then landslide deposits were initiated by continuous rainfall and evolved to a debris flow five days later, forming a secondary disaster chain. The rapid characterization of a landslide-debris flow chain (LDC) is a critical step in remediation works and future early warning of failure. This paper proposes a rapid disaster information integration and assessment method for providing information on LDC occurrence, failure mechanisms, and potential hazard-affected areas via examining and characterizing the Tiejiangwan LDC based on multi-method including geomorphological mapping, structural characterization, kinematic analysis and numerical simulation. The results suggested that the first landslide initiated from a mountain ridge that experienced historical deformation extended over the fractured argillaceous siltstones. Constrained by three discontinuity sets, the failure mode was determined as planar failure along a sub-vertical defect. The cause of first landslide can be attributed to a jointed effect of structural plane, tectonic activity, terrain and slope structure, while rainfall is the dominating triggering factor. Deposits with loose structure subjected to persistent rainfall and gully topography contribute to the occurrence of secondary debris flow. Using UAV and LiDAR identification, the unstable elements in the surrounding cliffs of the source area are derived and a three-dimensional simulation was implemented to detect the energy, velocity, height and reach of detached blocks. The proposed method leads to rapid characterization of LDC and assists the evaluation of cliff instability of these environments. Highlights: We proposed a rapid and integrated assessment system for landslide-debris flow chain occurrence, failure mechanisms, and potential hazard-affected areas identification. Quantitative study was conducted on the evolution from landslide deposits to debris flow. 3D simulation was performed to reveal the runout behaviors of surrounding potential dangerous rockfall areas. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Equivalent load cycle sequence (ELCS) is important basic information to know that affects the reliability of the evaluation of wind-induced fatigue on metal roof claddings. In this study, an estimation method of wind-induced fatigue of metal roof claddings is proposed. Based on the measured wind pressure–time history data of the roof claddings on a full-scale low-rise building located along the coast of South China during a typhoon, a new ELCS (NELCS) that reflects typhoon and actual structure wind pressure characteristics in China's coastal areas is obtained by using the rainflow counting method. The locations of fatigue hot spots of metal roof panels are analyzed by using the finite element analysis method, and the relationship between hot spot stress and wind pressure is obtained. The fatigue damage accumulation of metal roof claddings under the ELCS of a typhoon process is counted by the linear cumulative fatigue theory, commonly known as Miner's rule. The fatigue damage accumulation of roof claddings with different purlin distances and design wind loads is analyzed using this method and then compared with the results from the dynamic loading test of an air chamber. Results show that the physical test findings are close to the numerical calculation results, which proves that the numerical calculation method has high accuracy and reliability. The comparison between NELCS in this study and the Australian standard low-high-low (LHL) sequence shows that the LHL loading sequence is conservative. [ABSTRACT FROM AUTHOR]

The problem of excessive wear of pantograph strips frequently occurs on China's Z City Metro Line 1. After on-site investigation and analysis by the metro operating company, it was speculated that the problem was related to abnormal track irregularities. Therefore, taking Z City Metro Line 1 as the main research object, the measured track irregularity of the whole line was analyzed and compared with other typical track spectra, and a track-vehicle-pantograph-catenary coupling dynamics model was established to analyze the relationship between the pantograph-catenary dynamic characteristics and the track irregularity. The two frequency ranges of the track irregularity that have a significant impact on the pantograph-catenary contact were found. Finally, after numerical calculation and analysis, it is recommended to focus on the irregularities with the two wavelength ranges of 9~16 m and 3~4 m in the maintenance. [ABSTRACT FROM AUTHOR]

The prefabricated vertical drain (PVD) is an essential means to mitigate the settlement of soft soil foundations in coastal areas of South China. The commonly used elastoplastic analytical method cannot directly reflect the interaction of different PVDs and the resulting displacement of soft soil. At the same time, these elastoplastic analysis and numerical simulation methods are greatly influenced by the values adopted for rock and soil material parameters. In this paper, we present a stochastic medium model that can directly reflect the interaction of different PVDs and the resulting displacement of soft soil. It is not affected by the characteristics of rock and soil themselves and can also reflect the actual deformation process of soft soil. According to engineering practice, the settlement curves of soft soil foundations in coastal areas of South China with PVDs exhibited distinct normal distribution characteristics, which was consistent with the description of settlement by the stochastic medium model. Hence, based on the stochastic medium model, this paper analyzed the settlement mechanism of PVDs and established a stochastic medium model for the settlement calculation of PVDs. A function for the soft soil foundation in the coastal area of South China cross-section settlement curve was presented by back analysis of the PVD model. We chose the stochastic medium model based on this methodology to explore the interaction between different PVDs. The above models were then applied to an expressway in South China. Comparing actual settlement monitoring values to calculated values obtained with the PVD model, the error between the two models was less than 15%. This research provides a new settlement calculation method of PVDs in soft soil foundations in the coastal area of South China and a new basis for designing soft soil foundations. [ABSTRACT FROM AUTHOR]

With the rapid development of agriculture in China today, the demand for agricultural machinery is rapidly increasing. A large amount of exhaust gas emissions poses a severe threat to the environment. To better promote engine fuel and air mixing, enhance engine performance, and achieve low emissions, we conducted a numerical study of the pre-chamber and nozzle design in a gasoline engine for an agricultural tractor by using the G-equation method in Converge CFD software. The relevant optimization of the three model parameters in the G-equation was performed using the improved particle swarm algorithm (PSO). The model parameters after optimization by the PSO algorithm were: a 1 = 0.77 , b 1 = 2.0 , b 3 = 1.0 . It was confirmed that the predicted engine performance was enhanced greatly with the pre-chamber system. More importantly, the results reveal that the volume and area ratios of the pre-chamber played a crucial role in the performance of the pre-chamber. Through a series of parametric studies on the pre-chamber and main chamber characteristics, we can identify the best sets of volume and area ratios based on the combustion reaction progress, the turbulent mixing profiles, and the exhaust gas emission. The turbulent maximum strength and the exhaust gas concentration of nitrogen oxides can differ by 13 and 18 times, respectively. In practical design, we recommend the optimization of the concerned metrics with the findings in the paper. [ABSTRACT FROM AUTHOR]

This paper developed a quantitative evaluation necessary to ensure ground stability, so a quantitative indicator (bearing capacity). A homogeneous axisymmetric model was generated, considering China's stress field and the Karst topography characteristics, simultaneously obtaining stress component expression. We then determined the bearing capacity calculation formula by combining the strength theory of shear failure and the stress component expressions. Finally, the comparison of the bearing capacity calculation results between theoretical analysis and a numerical simulation indicated that the error was less than 5%, and the result verified the rationality of the formula. [ABSTRACT FROM AUTHOR]