A Numerical Analysis For The Fault Zone Influence On Surrounding Rock Stability Of Tunnel Construction In Aquifer Strata

Tunnel engineering becomes more and more used to pass through the mountains and enhance the road grade. The complex geological condition and non-even seepage flow have been the familiar points in tunnel engineering. The surrounding rock forms the new discharge passage after tunnel excavation, and intensifies the interactions between water and rock. The ground water weakens the rock strength and increase the difficulty of construction. Therefore, the study on coupled fluid-solid module and the stability of surrounding rock plays an important role.Although some researches on the stability of surrounding rock with crushed zone have been done, which based on the coupled fluid-solid theorem, they are still insufficient. Few publications have been available for the stability of surrounding rock with crushed zone. Researching the distributing rule of external water pressure on lining in aquifer strata becomes an increasingly important issue. This essay makes analysis on the stability of surrounding rock in view of the tunnel in aquifer strata which contains crushed zone. This essay discusses the calculation method of external water pressure on lining, and optimizes the drainage system.Considering of the effect of the coupled fluid-solid theorem, this essay employs numerical simulation method to obtain the characteristics of displacement, seepage field, principal stress and plastic zone to the crushed zone in different angles and different height of water table. The result of this essay shows that as the dip angle of crushed zone enlarges and water table rises, surrounding rock accelerates to destroy and the scope of plastic zone is extending gradually so that the areas of unsteady surrounding rock are enlarging simultaneously.Based on the coupled fluid-solid theorem, this essay analyze the distribution of external water pressure on lining, the influence of high hydraulic pressure to the stability of surrounding rock and the acting force on the lining, thus propose the controlled drainage in tunnels. By calculating the external water pressure on tunnel lining, we propose that providing drain hole in the crushed zone is more conducive to the safety of lining in view of the tunnel in aquifer strata.