Study On The Seismic Damage Mechanism Of Tunnels Through Fault And The Anti-Seismic And Damping Measures

Wenchuan earthquake damage survey indicates that each tunnel through fault has more serious damage in fault section than common segment, so fault section is key point in seismic fortification. This paper studies seismic damage mechanism of tunnels through fault. Based on differences of fault seismic response, mechanism research includes two sections, one is slip fault seismic damage mechanism research, another is non-slip fault seismic damage mechanism research. In non-slip fault section, the through fault tunnel seismic damage influents of difference in fault width and tunnel depth is studied, and the variation is found. In slip fault section, the tunnel seismic damage influence between fault slip and seismic inertia force caused by earthquake is studied, and the primary factor is determined. The tunnel influence of different direction of fault slip is researched, and the most unfavorable slip direction is determined. According to the seismic damage survey, the seismic damage mechanism in multiple fault types is studied also, which provides different condition to fortify. In addition, the safety distance between tunnel and fault is determined by digital simulation in condition that tunnel is parallel to the fault, which provides the basis for fortification. On the basis of mechanism research, the fortification measures for different condition are studied. The damping effect between different spacing of damping seam is studied, and the best spacing for damping is determined. The damping effect of staggered damping seam is studied, in contrast to common damping seam. The damping effect between different thick of damping layer is studied, and the best thick for damping is determined. The two kinds of anti-seismic measures are studied:contact grouting and deep grouting, and the most effective kind is determined.