软土地区地铁隧道顶部空洞对隧道动力特性影响的试验研究

Experimental study on dynamic characteristics of tunnel in soft soil area of subway tunnel

针对软土地区地铁隧道顶部出现空洞对隧道主体动力性能的影响进行了振动台试验研究。以某市地铁隧道为依托工程,建立了隧道缩尺模型及其所处软土环境,模拟出软土地下隧道顶部出现空洞的状况,分析了隧道顶部空洞处地震加速度响应、地震动应变及震后隧道破坏形态。试验结果表明:隧道衬砌顶部空洞的存在使得空洞附近出现较大动力效应,出现较大的动力响应和变形;衬砌的顶部空洞使得隧道顶部的围岩加速度响应和应变加剧,同时使拱腰加速度响应及应变也有一定的放大效应。隧道顶部空洞在地震时会加重震害。

In the soft soil area,the influence of the hole in the top of the subway tunnel on the dynamic performance of the tunnel is studied by shaking table test. Based on the project of Tianjin subway tunnel, established of the scale model tunnel and the soft soil environment and the condition of the hole in the top of the soft soil tunnel is simulated, so as to analyse tunnel＇s top hole seismic acceleration, vibration and earthquake damage morphology of tunnel strain. The experimental results show that the existence of the void in the top of the tunnel lining causes large dynamic effect, appears larger dynamic response and deformation; lining the top of the hole made on top of tunnel surrounding rock acceleration response and strain intensifies, and the arch waist acceleration response and strain also has a certain amplification effect. Hole at the top of the tunnel will increase damage when the earthquake.