群洞效应对紧邻交叠盾构隧道及场地土地震响应影响的初步分析

随着地下空间开发利用的深度和广度的进一步发展，近距离、复杂、相互穿越的大型地下空间工程必将大量涌现，各地下工程必将影响到其他相邻地下工程的抗震性能。以武汉地铁二号线和四号线工程在洪（洪山广场站）中（中南路站）区间的紧邻四孔交叠盾构隧道为依托，建立不同隧道数目的计算模型，分析了00093;群洞效应00094;对近距离多孔盾构隧道地震响应以及对场地土动力特性的影响规律。计算分析结果表明：①下卧隧道能在一定程度上阻断地震波的传播，起到减震的作用；②上层隧道的存在降低了周围土层对邻近隧道的约束作用，即降低了邻近隧道的抗震性能；③00093;群洞效应00094;对场地土基本周期以及地表加速度放大效应的影响均不显著；④浅层上覆土层对隧道抗震性能及场地土加速度放大效应影响显著。

Effect of group cavities on seismic response of adjacent overlapping shield tunnels and site soils

More and more adjacent, complicated underground structures will run across each other with the further exploitation and utilization of underground space, and hence, the seismic ability of underground structures will be influenced by the adjacent underground structures. Focused on the subway tunnels between Hongshang Square Station and Zhongnan Road Station on Wuhan rail transit lines No. 2 and 4, the relevant models for different numbers of tunnels and different tunnel net distances are established, and the seismic responses of tunnels and site soils influenced by group cavities effect are analyzed. The results show that: 1) the lower tunnel can cut off the transmission of seismic waves, and therefore, it can play the function of shock absorption; 2) the existence of the upper tunnel weakens the constraining effect of surrounding soils on the adjacent tunnel, and as a result, the seismic ability of the adjacent tunnel will be reduced; 3) the group cavities have little effect on the fundamental period of soils and acceleration magnification effect; and 4) the shallow overlying soil has a significant effect on the seismic ability of tunnels and acceleration magnification effect of site soils.