软弱地基上地铁区间隧道周围场地位移和加速度反应分析

Analysis on the nonlinear dynamic soil-metro tunnel interaction in thick-soft site-displacement and acceleration response

地下隧道是一种抗震结构,具有较好的抗震性能,但从已有地下隧道的震害资料和地下管线的震害特点,地下隧道穿越软弱土层时周围土体的相对大位移与坍塌将会对地下隧道造成严重的破坏,因此有必要开展对软土场地上地铁地下结构的抗震性能研究。根据南京地区地铁一号线建设的实际背景,选取南京某一典型深厚软弱地基上双洞单轨区间隧道为研究对象,建立了土-地铁区间隧道非线性动力相互作用的有限元分析模型,分析了3种不同埋深条件下南京地区深厚软弱地基上地铁区间隧道的动位移和加速度反应特性。结果表明,软土层中隧道结构顶、底板之间的相对位移很大,同时,SSI效应对软土层中隧道位移反应的影响也很大。

Underground tunnels are usually considered to have good earthquake resistant behaviors. But as far as those earthquake damages of underground pipelines are concerned,underground tunnels can be damaged severely by the large relative distortion of surrounding soil layers. Accordingly,earthquake resistant behaviors of underground tunnels must be studied in detail. By considering the characteristics of soft soils in Nanjing,a representative soft site is selected as the groundwork of tunnels. By using ABAQUS finite-element software,the nonlinear dynamic soil-metro tunnel interaction is modeled by finite-element. The displacement and acceleration response of tunnels buried in three different depths are analyzed respectively. Results show that the relative displacement between the top and bottom of tunnels buried in soft site is very large. At the same time,the soil-structure interaction has a great effect on the displacement responses of tunnels.