STUDY ON SURROUNDING ROCK DEFORMATION OF LARGE BURIED DIVERSION TUNNEL THROUGH FAULT ZONE

Fracture zone is a common bad geological phenomenon in the process of deep tunnel excavation. Taking Xianglushan tunnel of Central Yunnan Water Diversion Project as the engineering background, the deformation of surrounding rock on both sides of the arch, arch bottom and arch waist of the tunnel is studied by establishing the numerical model of tunnel excavation through the fault zone, and the influence of tunnel through different fault zone widths, dip angles, strike and buried depths on the deformation of surrounding rock is further analyzed. The results show that due to the existence of fault zone, the vertical displacement and horizontal displacement of surrounding rock change obviously. The closer the tunnel is to the core of the fault zone, the greater the deformation of surrounding rock on both sides of the tunnel arch, arch bottom and arch waist, and the deformation of surrounding rock near the center of the fault zone reaches the maximum value. The vertical and horizontal displacements of the surrounding rock increase with the increase of the width of the fault zone and the buried depth of the tunnel, and decrease with the increase of the inclination of the fault zone. The variation of fault zone strike has little effect on the vertical and horizontal displacements of surrounding rock. For vault settlement, the influence degree of comprehensive factors from small to large is the strike of fault zone, the dip angle of fault zone, the width of fault zone and the buried depth of tunnel.