| Tunnel leakage has always been a problem for domestic and foreign experts,scholars and builders.China has made a long time to deal with the problem of tunnel leakage.Many large-scale sudden flooding accidents occurred during the process of high pressure mountain tunnel construction,and the tunnels that have been built and put into operation exist water leakage defects in the vast majority,besides many environmental problems caused by tunnel drainage are grave at the same time.These problems are in serious conflict with the increasingly environmental protection problems and the rapid growth of traffic demand caused by economic development.Therefore,the study of tunnel water treatment is particularly urgent and significant.In order to prevent the high pressure karst tunnel instability,combined with the domestic and foreign water inrush disaster case,relying on the State Administration of production safety supervision and management project "Karst tunnel bridge tunnel transition section of surrounding rock stability and construction mechanics behavior" and the Science and technology project of Sichuan Education Department "Research on the mechanism and prevention measures of karst tunnel water inrush disaster" Based on Yuanliangshan tunnel,starting with a large number of relevant information and literature,through the literature research,the key issues to deal with the problem of tunnel water need to count on the tunnel lining structure of the water pressure calculation and reasonable water treatment methods,based on the comparative analysis between theoretical analysis and engineering example statistics,combined with the basic seepage theory,the problem is simplified rationally,and analyzed the calculation formula of the lining water pressure obtained from the calculation based on the hypothetical under the relevant conditions.The theoretical derivation has been supplemented and analyzed combined with the numerical simulation and field engineering application,so as to solve the problems and difficulties in the design and construction of high pressure karst tunnel.The main research results are as follows:(1)Through theoretical analysis,confirming the water blocking and limiting discharge mode as the main research direction,through 10 data statistics of tunnel water disasters occurring from construction to operation period and water pressure influence factors and characteristic analysis,showing the intimate connection lining water pressure and the geological condition,so taking the location relationship between the tunnel and different permeability coefficient of strata as the main breakthrough.(2)Through the characteristics of the groundwater driftnet,the calculation model of the infiltration layer of infinite aquifer in the tunnel and the stratum is simplified.Using the basic theory of rock mass hydraulics and seepage mechanics combined with mathematical physics,the expression of water pressure of tunnel lining and water inflow with different position is deduced,and the formation water grouting consolidation circle correlation coefficient was analyzed and the effect of the composite lining for water pressure,water pressure distribution,water efficiency and water inflow was also analyzed,and the reasonable value of inject grouting area is obtained.(3)According to the Yuanliangshan tunnel on Yuhuai Railway as the simulation object,the FLAC3D was used to simulate the different parameters of grouting reinforcement under different conditions.The seepage field of the’ surrounding rock of the tunnel and the distribution of the water pressure behind the secondary lining are obtained under the condition of different formation,tunnel location and working condition.(4)The characteristics of water pressure distribution and the related influencing factors were analyzed according to the characteristics of Yuanliangshan tunnel and the monitoring of water pressure.In comparison with the theoretical results and the numerical simulation results,the rationality of the theoretical derivation and the correctness of the calculation expressions are verified,it can provide reference for the analysis and calculation of water pressure in practical engineering. |
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