The Study Of The Coupled Effect Between Seepage Field And Geostress Field In The Tunnel Of Daxiangling

The seepage field and stress field coupling theory is a hot issue in the recent year at home and abroad. The study on the issue is of great significance for promoting scientific and technological progress and solving practical engineering problems. First, the characteristics of seepage of fractured rock mass are systematically summarized and the interaction effect between the seepage field and stress field of the fractured rock mass is obtained. Then coupling analysis method of fractured rock mass is described.Da Xiang Ling Tunnel is located in the transition mountains margin of the Sichuan basin and Qinghai-Tibet Plateau. In margin region faults and fracture developed and hydro-geological conditions, seepage field and stress field are complicated. Seepage field and stress field conditions are also very complex. Therefore, Based on the hydro-geological conditions of Da Xiang Ling Tunnel, through systematic analysis of date related drilling, hydrological condition etc. of tunnel site, it is obtained that the seepage character of the rock mass in the tunnel area, the distribution of the ground stress in the tunnel area, the permeability coefficient and storage coefficient of the rock mass. It is also studied that the coupling reaction scope between seepage field and stress field and the characteristics of stress redistribution caused by the tunnel excavation using the numerical simulation. Also on this basis, the redistribution of the seepage field led by stress redistribution and the coupling phenomena of the fluid-structure interaction are gotten.Simultaneously, it is simulated that the tunnel excavation cases in coupling and non-coupling considering the fault effect. In the coupled case, the stress redistribution is different from that in non-coupled, and strain scale than non-coupling cases increased by 9%-32.8%. It is illustrated the fluid-structure coupling interaction has a great impact on the tunnel construction safety.At last, it is simulated that the rock failure modes in excavation with cavity in rock mass considering the coupling. The stress concentration of the cavity is more obvious than that of the effecting district of tunnel after the excavation. After the collapse instability of the cavity rock, the collapse rock squeezes the water in the cavity. So the water pressure is surge and hydrodynamic pressure and hydrostatic pressure have interaction with surrounding rock which stress is redistributed. After the coupling effect, the surrounding rock mass of the tunnel occur instability, and phenomenon of water gushing and collapse take place.