为了分析岩溶区下伏溶洞空腔的嵌岩桩基稳定性，以湖南省益娄高速公路大塘村大桥的桩基为研究对象，利用有限差分软件 FLAC3D 建立了考虑实际地层情况及溶洞空腔的三维数值计算模型，并通过枚举法设计了不同嵌岩深度及顶板厚度的分析工况。研究结果表明：随着嵌岩深度的增加，顶板塑性区会逐渐贯通并产生拉剪破坏；当嵌岩深度为2 m、顶板厚度为3 m 时，桩基底部及空腔附近一定区域产生较小的应力集中，桩顶、桩底及顶板的的变形沉降量较小，可以满足桩基稳定性的要求。%In order to analyze the stability of rock-socketed pile foundations in karst area,the pile foundation of the Da Tang-cun bridge in Yi-Lou highway was chose as the research object,the FLAC3D software was used to build the three dimensional numerical calculation model on the condition of actual geological and the analysis conditions of the different rock-socketed depth and karst cave roof thickness were designed by enumeration method.The results show that:With the increasing of rock-socketed depth,roof plastic zone connected gradually,and it led to tension-shear failure;When the rock-socketed depth is 2m and roof thickness is 3m,the smaller stress concentration took place at the bottom of pile and near the area of cavern,the displacement at the top of pile,bottom of pile and roof are small,which can satisfy the requirement of the stability of the pile foundation.
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