溶洞上方条形基础地基极限承载力有限元分析

Finite element analysis of ultimate bearing capacity of strip footing above Karst cave

针对岩溶地区典型围岩条件,采用有限元方法对岩溶地区条形基础下溶洞顶板稳定性进行分析计算,得出溶洞顶板跨度、顶板厚度不同时地基的极限承载力;分析了极限承载力与各影响因素之间的关系,给出了溶洞顶板安全厚度的有限元分析结果。研究结果表明:溶洞顶板厚度在一定范围内,当顶板跨度从B增加到4B时,地基极限承载力降低1/3;当跨度一定时,地基极限承载力随溶洞顶板厚度增加而增加;当顶板厚度达到安全厚度时,溶洞对地基极限承载力影响可以不计。

The ultimate bearing capacity of surface strip footings located above a cylindrical rock void whose axis parallels with the footing axis was investigated. The performance of strip surface footings with and without an underground void was studied using the finite element method. For each footing, there exists a critical depth below which the presence of the void has negligible influence on footing performance. The ultimate bearing capacity values were obtained from the results of analysis and were related graphically to the influencing factors. The results show that the ultimate bearing capacity of foundation drops 1/3 when the width of rock plate upper cave increases from B to 4B within the limits of depth. As the width of rock plate upper cave is certain, the ultimate bearing capacity of foundation increases with the depth, and the caves have little effect on the ultimate bearing capacity of foundation when rock plate upper cave reaches a critical depth.