Risk Evaluation of Water Inrush in Dengloushan Tunnel Using Entropy-Catastrophe Method

As a common geological hazard in karst areas, the water inrush has been a great threat to tunnel construction. Therefore, a reasonable risk evaluation of sudden water inrush is the key to tunnel construction. Based on the combination of the entropy method and catastrophe theory, a risk evaluation system of water inrush for tunnel excavation has been established in this study. Taking the ventilation incline of Dengloushan tunnel from Yunnan as an example, the entropy method is applied to rank the importance of seven target segments with different geological condition. After that, the corresponding catastrophe models are selected for each group of evaluation indicators, and the catastrophe affiliations are calculated layer by layer to evaluate the system. The results show that the accuracy of model calculation is in good agreement with practical engineering situation: the three main locations, where concentrated water inrush occurred during the excavation of the ventilation incline, are next to the evaluation segment X6, and the total catastrophe affiliation calculated by the entropy- catastrophe theory model belongs to the extremely high risk. This study provides an effective scientific basis for identifying the water inrush location in Dengloushan tunnel construction, and the relevant conclusions can be used as a reference for other tunnels with similar geological conditions.