长江一级阶地岩溶塌陷对地铁车站结构影响研究

Study on the influence of karst subsidence in the first terrace of Yangtze River on the structure of subway station

针对武汉长江一级阶地岩溶塌陷区或类似地质条件下的地铁车站结构设计,分析长江一级阶地岩溶地质特征以及溶洞分布规律,提出岩溶塌陷区地铁车站概化分析模型,对车站范围岩溶塌陷机理进行分析。据此进一步建立三维有限元模型,对不同岩溶塌陷空腔程度下车站结构受力及变形进行对比研究。结果表明,车站底板处于塌陷扰动区时,其受力和变形受塌陷坑尺寸影响较大;塌陷区易造成结构相对位移差或土体承载力不够,可能影响车站的结构安全;采取适当的基底处理措施阻止岩溶的继续塌陷,辅以一定的结构跨越承托措施,有利于预防不确定因素引起的岩溶塌陷。研究结果可为此类地质条件下地铁车站设计及选择合适的岩溶处理方案提供参考。

Aiming at the structural design of the subway station in the karst collapse area in the first terrace of Yangtze River in Wuhan or other places with similar geological conditions,the karst geological characteristics and the distribution law of karst caves in the first terrace of the Yangtze River were analyzed.The generalized analysis model of the subway station structure in the karst collapse area was proposed,and the karst collapse mechanism within the station was analyzed.A three-dimensional finite element model was established to conduct a comparative analysis of the stress and deformation of the station structure under different degrees of karst collapse cavities.The results show that when the station baseplate is in the collapse disturbed area,its stress and deformation are greatly affected by the size of the collapse pit;the collapse area is easy to cause the relative displacement difference of the structure or the insufficient bearing capacity of the soil,which may affect the structural safety of the subway station;it is helpful to prevent karst collapse caused by uncertain factors to adopt appropriate basement treatment measures to prevent the continuous collapse of the karst,supplemented by some structural spanning or supporting measures.The research can provide reference for the design of subway station and the selection of appropriate karst treatment schemes under such geological conditions.