泡沫混凝土减震层对隧道地震响应影响分析

应用有限差分软件FLAC^{3D对泡沫混凝土减震层对花岗岩隧道地震响应的影响规律进行分析. 综合考虑围岩位移、塑性区范围、应力场分布、应变增量等指标,得出增设泡沫混凝土减震层可以大幅降低围岩最大主应力以及衬砌结构的内力,有利于围岩的稳定.其次分析了减震层各物理力学参数对花岗岩隧道地震响应的具体影响,得出增加减震层变形模量或粘聚力可以大幅降低衬砌结构中的内力；而减震层的内摩擦角及泊松比的改变对减震层的减震效果影响较小.}

Analysis of influences of foam concrete buffer layer on seismic responses of tunnels

The influences of foam concrete buffer layer on a granite tunnel during earthquake are analyzed using the finite-difference program FLAC^{3D. Based on the studies of displacements, plastic zone, stress field, strain increment of surrounding rock, it can be concluded that the maximum principal stress of surrounding rock and the inner force of liner are reduced significantly by setting foam concrete buffer layer. It is beneficial for the stabilization of tunnel. Then the influences of physical-mechanical parameters of foam concrete are analyzed respectively. It is shown that the inner force of liner is reduced rapidly by increasing the modulus or the cohesive of buffer layer. But the changing of the internal friction angle and Poisons ratio take little influence on the effect of damping of buffer layer. Results of this research can provide certain references for seismic design of granite tunnel.}