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.

Disordered mining activities have significantly affected the eco-geological environment of groundwater in mining area. Based on the fuzzy set theory, this paper considered three factors: the quantity of groundwater resources, groundwater environmental quality and groundwater vulnerability, and established a multi-index and multi-parameter non-linear evaluation system to make a comprehensive evaluation of the groundwater environment in the mining area. The results showed that the groundwater eco-geological environmental issues in this region were serious. The distribution area of poor quality of groundwater environment was very large, accounting for 72.5% of the studied area, and it mainly distributed in the middle and southern regions. The areas with general groundwater quality covered about 19.0% and mainly distributed in the central and northern parts in a strip shape. The areas with good groundwater quality covered about 8.5% and distributed sporadically. Moreover, in the study area, because the groundwater vulnerability was at a high level and the groundwater environmental quality was poor, the groundwater was extremely susceptible to contamination. Therefore, the groundwater environment in the area should be significantly protected during coal mining. In addition, the predicted results can provide a scientific reference for the planning and sustainable development of large coalfields.

Currently, gas disasters in tunnels occur frequently and cause severe casualties and property losses. However, there are few studies on the risk assessment of gas tunnels, especially comprehensive analysis of the safety risk of gas tunnels considering multiple factors. This paper presents a comprehensive assessment method for safety risk of gas tunnel construction based on fuzzy Bayesian network. The results of safety risk assessment are determined by two aspects: risk probability and risk hazard. In the process of assessment, 12 risk indicators were extracted from 32 important factors by the principal component analysis method, and a fuzzy interpretative structural modeling was established and converted into a fuzzy Bayesian network to evaluate the risk probability. The risk index weight was obtained through principal component analysis, and the risk hazard level was calculated by using the fuzzy comprehensive assessment method in combination with the hazard degree of the risk index. After a comprehensive assessment of gas concentration and other field conditions, the relevant parameters such as the fuzzy interpretative structural modeling and fuzzy Bayesian network are determined. This paper selects two construction segments of the Like tunnel as case studies to verify the feasibility and application prospects of this method. The method establishes a safety risk assessment model for gas tunnels, which can allow management personnel to fully evaluate gas tunnel risk and provides a safe construction environment.