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Leakage of lining structure is one of the main geological disasters of the tunnel, which brings heavy economic losses and casualties. Aiming at the problem of lining leakage of the Kaiyuan Tunnel in Jinan, this research has carried out a geological survey, conducted statistics, and classification of the leakage situation of the Kaiyuan Tunnel. The causes and main control factors of various types of seepage are analyzed. To locate the leakage accurately, electrical resistivity tomography, transient electromagnetic method, and ground penetrating radar are used to carry out comprehensive geophysical exploration. Two catchment zones and fractured zones are determined based on the existing geological topographic maps, geological profile maps, and geological analysis results. Transient electromagnetic detection results coincide with the known fractured zones, which confirms the existence of fractured zones and defines the scope of fractured zones. Moreover, the detection results based on ground penetrating radar show that the main adverse geological conditions inlining and surrounding rock are water diversion area, hidden water diversion area and surrounding rock fragmentation area. Subsequently, three kinds of grouting material, ultra-fine cement, ordinary Portland cement, and polymer cement, were selected for seepage control of the 800–900 m and 1310–1330 m test sections for plugging treatment. The grouting effect was analyzed and evaluated based on ground penetrating radar detection and field working conditions. Especially, the grouting radar detection shows that the grouting effect of polymer cement slurry is ideal, the grout in the water conduction area is basically filled, and the lining cracking and damage have been significantly repaired and improved. This paper verifies the accuracy and good feasibility of the interpretation criteria of comprehensive geophysical detection for typical lining defects, which can be popularized and applied in relevant tunnels and underground projects.

The characteristics, heterogeneous distribution and origins of carbonate cements within beach-bar sandstones in the Boxing Sag and implications on the mass transfer from mudstone to sandstone during diagenetic process was investigated systematically by an integrated analysis invoking petrography, carbon and oxygen stable isotopes and porosity-permeability, with specific references to the contrasts among the sharp (S)-change lithology (S-mudstone-S-sandstone interbeds), the gradual (G) -change lithology (G-mudstone-G-sandstone interbeds) and the center of sandstones. There are distinct differences in the occurrence, content, distribution, carbon and oxygen isotopic compositions and precipitation temperatures of the carbonate cements among the S-sandstone, G-sandstone and center of sandstone. Material sources of carbonate cements in the S-sandstones are mainly derived from the diagenetic alterations of the nearby S-mudstones through mass transfer with the participation of organic CO2, while in the G-sandstones, the material sources are mainly internal and originated from the calcareous matrix. Dissolution of feldspars and conversion of clay minerals provided the main materials for the precipitation of carbonate cements in the center of sandstones. Mass transfer of carbonate cements mainly occurred between the S-mudstones and the S-sandstones with limited transmission distance, which controlled the distribution of carbonate cements in the S-mudstones. There was almost no mass transfer between the G-mudstones and G-sandstones because of the small concentration gradient, instead, the depositional components and recrystallization controlled the carbonate distribution of the G-sandstones.

Rock burst is a dynamic process involving the sudden release of elastic energy accumulated in overstressed rocks and coal masses during underground excavations, capable of causing a great number of fatalities, failure of supporting structures, and damage to equipment. To minimize the risk, a fuzzy comprehensive assessment model was established to predict and evaluate rock burst in underground caverns, and some indices were selected and analyzed. The result vectors and weight vectors were expressed by interval numbers and the membership degrees were determined by a sigmoid membership function. In addition, synthetic weight was obtained by combining subjective weight with objective weight, and final vectors were categorized into different levels through possibility ranking analysis. Finally, the proposed method was applied to a practical case, the Jiangbian hydropower station in China, for further verification. Considering that some indices were conceptually dependent on one another, the multicollinearity of these indices was evaluated according to results based on different indicator systems. The evaluation results showed a high consistency with the actual situation. Moreover, the indicator system, which made full use of the obtained data, had more reliable results than other indicator systems. The proposed fuzzy comprehensive assessment method provides valuable guidance for rock burst assessment.

A nonlinear fuzzy interval method for risk assessment of floor water inrush in coal mines was established, consisting of a multi-index evaluation system and a computational model. The multi-index evaluation system is formed by the destination, criteria, and indicator layers and the risk levels of floor water inrush were divided into five grades. Geological structure, hydrologic condition, the state of the floor aquifuge, and the mining condition were analyzed. Thirteen factors were considered as assessment indices. A computational model is proposed based on nonlinear fuzzy mathematics and the analytic hierarchical process (AHP). Considering the uncertainty of evaluation indices obtained from field exploration, the interval number was adopted to represent variables. Gaussian membership function was used to determine the membership function and membership degree, and the 1–9 AHP scales method was used to calculate the interval number judgment matrixes. The final evaluation levels were obtained by the relative superiority analysis method. The proposed method was successfully applied to the 13301 working face of the Wanglou mine and four additional coal mines in China. The results were highly consistent for these practical situations, which verify the reliability of this study.

Purpose Because of the properties of loess, the occurrence of collapse following deformation of a large settlement is a common problem during the excavation of tunnels on loess ground. Hence, risk management for safer loess tunnel construction is of great significance. The purpose of this paper is to explore the influence of factors on collapse risk of loess tunnels and establish a risk assessment model using rough set theory and extension theory. Design/methodology/approach The surrounding rock level, groundwater conditions, burial depth, excavation method and support close time were selected as the factors and settlement deformation was the verification index for risk assessment. First, using rough set theory, the influence of risk factors on the collapse risk of loess tunnels was calculated by researching engineering data of excavated sections. Then, a collapse risk assessment model was developed based on extension theory. As the final step, the model was applied to practical engineering in the Loess Plateau of China. Findings The weights of surrounding rock level, groundwater conditions, burial depth, excavation method and support close time obtained using rough set theory were respectively 10.811 per cent, 18.919 per cent, 24.324 per cent, 40.541 per cent and 5.406 per cent. The assessment results obtained using the model were in good agreement with field observations. Originality/value This study highlights key points in collapse risk management of loess tunnels, which could be very useful for future construction methods. The model, using easily obtained parameters, helps in predicting the collapse risk level of loess tunnels excavated under different geological conditions and by different construction organizations and provides a reference for future studies.

Water inrush in karst tunnels is a dynamic process in which internal and external factors are involved. The evaluation of this process is fuzzy, complex, and uncertain. In the current research, few articles give full consideration to the fuzziness and randomness of the water inrush evaluation with useful dynamic feedback. A new assessment method has been proposed for the water inrush evaluation based on a combination of the weighting method and normal cloud model. Specifically, an evaluation index system is forged and each index is quantitatively classified into four grades. A synthetic weighted algorithm combining the analytic hierarchy process, entropy method, and statistical methods is proposed to assign the index weight rationally. Based on the cloud generator algorithm, three numerical characteristics are calculated and a sufficient number of cloud droplets are generated. The membership degree of each index belonging to each grade is constructed and the integrated certain grades are determined. In this paper, the multi-factor normal cloud assessment method is applied to the risk assessment of the Qiyueshan tunnel. The assessment result of the risk grade is accurate, that is, the water inrush risk of different samples at the same risk grade can be reflected in figures. The results not only show high consistency with other assessment methods but are also in good agreement with the excavation results. The proposed cloud model method demonstrates good practical reference for risk assessment of tunnel construction in karst areas and can be applied to tunneling, mining, and other engineering practices in the future.

Springs are a source of drinking water and a famous tourist attraction in Jinan, China. In this paper, a multi-index evaluation method was proposed based on a normal cloud model. This model is new graphic model, which could synthetically picture the randomness and fuzziness of concepts. Ten parameters were selected, and water quality was classified into five levels. Three numerical characteristics were calculated, and the weights were assigned by an integrated weighting algorithm. The uncertainty of each spring was calculated by a cloud generator and the integrated certainty grades of water quality were determined. To ensure the accuracy of the normal cloud model, the proposed method was used to assess the water quality of springs in Jinan, China. The results obtained by the proposed method were compared with that of the other four methods. The results obtained by different methods are highly consistent. The proposed cloud model-based method can reflect the water quality level and provides a practical guide for water quality evaluation, as demonstrated in Jinan springs.

The emergence of wireless body area network (WBAN) technology has brought hope and dawn to solve the problems of population aging, various chronic diseases, and medical facility shortage. The increasing demand for real-time applications in such networks, stimulates many research activities. Designing such a scheme of critical events while preserving the energy efficiency is a challenging task, due to the dynamic of the network topology, severe constraints on the power supply, and the limited computation power. The design of routing protocols becomes an essential part of WBANs and plays an important role in the communication stacks and has a significant impact on the network performance. In this paper, we briefly introduce WBAN and focus on the analysis of the routing protocol, classify, and compare the advantages and disadvantages of various routing protocols. Lastly, we put forward some problems and suggestions, which provides ideas for the follow-up routing design.

Hydraulic tomography (HT) is a well-established approach to successfully describe subsurface hydraulic heterogeneity. This work explored the potential of HT and the simultaneous successive linear estimator algorithm to map the distribution and connectivity of karst conduits and their hydraulic parameters at the engineering scale. Three generalized synthetic karst conduit models, auxiliary conduit, cave and waterfall, were established. A series of pumping tests were conducted at different locations as forward simulations to collect hydraulic head responses. These responses were then used for the HT inversion analysis to estimate hydraulic parameter fields of karst aquifers under steady-state and transient conditions. Our results show that high-density observation wells substantially assist with interpreting the reliable spatial distribution of hydraulic parameters. With the increase in the number of pumping wells in the HT inversion, the estimates of hydraulic conductivity and specific storage became more accurate for the auxiliary conduit model, but for the cave and waterfall models, there was no significant improvement. The hydraulic conductivity (K) tomograms from transient hydraulic tomography (THT) better indicated the heterogeneity of the three karst models than those from steady-state hydraulic tomography (SSHT) because a large number of hydraulic head records were introduced into the THT inversion process. Moreover, when reliable geological data are available, the accuracy of the estimated hydraulic parameter maps can be greatly improved even if only infrequent hydraulic head measurements can be obtained, implying that a priori geological information may be extremely valuable in mapping karst conduit heterogeneity. Finally, the robustness of HT in mapping karst conduits is verified through the simulation of independent cross-hole pumping tests. This study proved that hydraulic tomography utilizing groundwater responses from a series of cross-hole pumping tests is an efficient and cost-effective way and provided a feasible method for accurate identification of hydraulic heterogeneity of karst aquifers.

The Late Paleozoic is considered to be an important stage in the evolution of the Central Asian Orogenic Belt (CAOB). The Bogda Mountains, a northeastern branch of the Tianshan Mountains, record the complete Paleozoic history of the Tianshan orogenic belt. The tectonic and sedimentary evolution of the west Bogda area and the timing of initial uplift of the West Bogda Mountains were investigated based on detailed sedimentological study of outcrops, including lithology, sedimentary structures, rock and isotopic compositions and paleocurrent directions. At the end of the Early Permian, the West Bogda Trough was closed and an island arc was formed. The sedimentary and subsidence center of the Middle Permian inherited that of the Early Permian. The west Bogda area became an inherited catchment area, and developed a widespread shallow, deep and then shallow lacustrine succession during the Mid-Permian. At the end of the Mid-Permian, strong intracontinental collision caused the initial uplift of the West Bogda Mountains. Sedimentological evidence further confirmed that the West Bogda Mountains was a rift basin in the Carboniferous-Early Permian, and subsequently entered the Late Paleozoic large-scale intracontinental orogeny in the region.

Scientific site selection can significantly reduce construction risk and cost during construction of underground petroleum storage. Based on the analytic hierarchy process (AHP) theory and ideal point theory, a new site selection model for large underground petroleum storage is established in this paper. Nine indicators are selected as evaluation indices, including joint development, natural water-sealed condition, rock mass strength, in situ stress, environmental ecological vulnerability, regional stability, technical and economic conditions, topography, and meteorological conditions. Based on AHP theory, the weight of each evaluation index is determined. Secondly, the positive and negative ideal solutions of these evaluation indices are determined using ideal point theory. The ideal point evaluation function of each evaluation index is built to calculate the degree of closeness for the evaluation samples. Finally, the accuracy of the model is verified by using the model to evaluate the first underground petroleum storage project in China. The results show that the first six indicators are main controlling factors, and the sum of their weight is 88.3%. The result of the evaluation site level is good (II), which is suitable for construction. Moreover, the feasibility and accuracy of the evaluation criteria, and evaluation method is verified after cooperation with the power coefficient method and expert evaluation method. The research results can provide some references to the site selection of similar key projects.

Many studies have focused on the tectonic evolution and sedimentary processes of the Beisantai Uplift, NW China during the late Permian. However, the sedimentary characteristics of the area are still not well documented due to a complex tectonic evolution of the uplift and the limited distribution of core data. To understand the sedimentary evolution of this study area, a “source-to-sink” system research is adopted. First, the research redefines the sequence stratigraphic framework of the late Permian, which corresponds to a complete third-order sequence that can be further divided into a transgressive system tract (TST) and a regressive system tract (RST). Then, the integration of three-dimensional (3D) seismic reflection data, well logs, mud logs and core data provides new insights into the transportation and sedimentary processes within the “source-to-sink” system. The different characteristics of the source area, transfer system and sedimentary paleogeomorphology between the TST stage and RST stage ultimately led to significantly different sedimentary characteristics in the two stages. In the TST stage, the “source-to-sink” system exhibited a continued transgressive depositional characteristic that matched the sediment discharge evolution. The steeper sedimentary paleogeomorphology enabled the development of large-scale fan deltas with few beach bars. During the RST stage, the “source-to-sink” system had low sediment discharge and a smooth sedimentary paleogeomorphology. The “source-to-sink” system was predominantly characterized by small-scale beach bars with few fan deltas. With the decreasing level of sediment discharge and continued smoothing of the sedimentary paleogeomorphology, the beach bars expanded.