Study Of Risk Assessment Of Inrush Water Hazards In Karst Tunnels

The inrush water geological hazards are common in Karst tunnels. Based on the projects—“Applied technology research of double wave advanced detector for water hazard in tunnels” respectively from Ministry of Science and “3D network simulation and hazards prediction of fractured rock tunnels based on GIS and theories of data mining” respectively from Technology and National Natural Science Foundation. This thesis take the inrush water hazards of Shanghai Kunming high-speed rail tunnel in Dadu mountain as study subject to do fatalness assessment of Inrush Water Geological Hazards in Karst Tunnels. The specific content and results of the study are as follows:1. According to the material from field survey, local relevant department and internet, this thesis introduces the regional geological environment background of Guanling Buyei and Miao Autonomous County from five aspects. And also studied the geological conditions of the Dadu mountain tunnel engineering area.2. Do classification research of water source storage types and inrush water forms in Karst tunnels according to the material collected. Analyzed the formation mechanism of water inrush disaster in karst area according to formation lithology, geologic structure, landform, karst hydrodynamic zoning and other unfavorable geological conditions.3. The assessment system of inrush water hazards in tunnels is established, by selecting 13 influence factors(lithology, rock structure, formation of strata, rock stratum contact zone, faults, folds, joint development degree, negative terrain area ratio, surface slope, vertical zoning of groundwater, groundwater level and tunnel location elevation difference, development of special soil and karst cave) from five aspects(Formation factor, tectonic factor, landform, hydro geological factor and other unfavorable geological conditions) according to the geological environment background of the Dadu mountain tunnel and the formation mechanism of inrush water hazards in Karst Tunnels. Do risk grade classification of each evaluation index. The attribute interval recognition model is used as the evaluation model in the thesis. Combination weight is established based on the analytic hierarchy process and entropy weight method.4. 10 typical segments in the Dadu mountain tunnel were taken as case studies. Quantized the every evaluation indexes for the calculation of attribute interval recognition model to establish the data base for calculation. AHP and entropy weight method were used to analyze the subjective and objective weight of each evaluation index. Combined the subjective and objective weight according to the smallest distance function calculation method, and combined weight. The single attribute measure intervals were calculated according to the classification standard of evaluation indexes. Combining with the attribute measure intervals and the combined weight of every evaluation indexes, the comprehensive attribute measure interval can be calculated. The risk levels of water inrush in karst tunnels of Dadu mountain can be estimated by the confidence criterion and the comprehensive attribute measures. Comparing the evaluation results with both the water inflow by predicted and part of the excavation materials, the evaluate results and the method of this thesis are objective and reasonable.