将强度折减法引入强震作用下的海底隧道衬砌结构安全稳定性研究，利用FLAC3D软件建立了海底隧道-岩土体-海水相互作用的强度折减法数值模型，综合考虑海底隧道衬砌在强震作用下的位移、剪应变增量和塑性区变化，确定了海底隧道衬砌局部破坏的极限平衡状态和整体破坏的极限平衡状态，分析了海底隧道衬砌在强震作用下的破坏机理。结果表明：海底隧道衬砌在水平地震波的作用下，主要是围岩变形导致隧道衬砌破坏；隧道衬砌破坏位置发生在右侧侧墙中部，破坏形式为剪切破坏；隧道衬砌局部破坏的极限安全系数为1.47，整体破坏的极限安全系数为1.8，2种安全系数的极限状态可对应结构设计中的正常使用极限状态和承载力极限状态。研究成果可为海底隧道衬砌设计提供理论依据。%Strength reduction method is introduced into safety and stability research on subsea tunnel linings under strong seismic effects. A numerical model of the strength reduction method on the interaction between subsea tunnel, soil and seawater is established by means of FLAC3D software. Based on changes of displacement, shear strain increment and plasticity states of subsea tunnel linings under strong seismic effects, the limit equilibrium states for both local failure and overall failure of linings are determined and seismic failure mechanism for subsea tunnel linings is analyzed. The results show that under the effects of horizontal seismic waves, subsea tunnel linings are destroyed mainly because of the deformation of surrounding rocks. The destruction of tunnel linings, which is in the form of shear failure, takes place in the center of right sidewalls. The ultimate factor of safety of the local failure of tunnel linings is 1.47 while that factor of the overall failure is 1.8. The limit states of the two safety factors can correspond to the limit states of both normal usage and the bearing capacity. Research results provide the theoretical basis for the design of subsea tunnel linings.
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