水底液化地层大型盾构隧道地震响应分析

 建立南京长江盾构隧道主隧道、横向疏散通道及地层相互作用的三维模型，采用Byrne模型模拟地层的循环液化，对模型分别输入横向和纵向地震波，研究结构一般部位及主隧道–横向疏散通道交叉接口部位的动力力学(应力和位移)响应特征，并分析了横向和纵向地震波对地层孔隙水压及有效应力的不同影响。分析结果表明：横向激振对结构的损害远大于纵向激振，主隧道–疏散通道交叉接口部位在横向激振动力作用下拉应力峰值约3 MPa，超过结构极限抗拉强度，有拉裂破坏的趋势。最后，提出了结构的抗震措施建议，研究结论有利于类似工程抗震设计。

STUDY ON SEISMIC RESPONSE OF LARGE SHIELD TUNNEL IN SUBMARINE LIQUEFIABLE STRATA

Employing Byrne model to simulate cyclic liquefaction of soils，a three-dimension model that consists of main tunnels，transverse evacuating passage and strata of Nanjing Yangtze River tunnel is established to study structure dynamic mechanical(stress and displacement) responses by inputting transverse and longitudinal seismic waves；and the different influences of transverse and longitudinal seismic waves on pore water pressure，effective stress are studied. The conclusion shows that the damage of transverse earthquake excitation to structure is much more serious than that of longitudinal earthquake excitation，and that the peak value of maximum tension stress of intersecting section of main tunnel-evacuating passage is about 3 MPa under transverse earthquake excitation，which is over the ultimate tensile strength of structure and will lead to a failure tendency of tension fracture. An aseismic mitigation method was proposed，and the achieved conclusion is helpful for the aseismic design of similar projects.