研究目的：合理地确定岩溶地区土洞地基的承载力。
研究方法：根据弹塑性理论，推求得到岩溶地基中土洞周边土体的应力状态。在土体自重应力和基底附加压力的作用下，土洞周围的土体将产生应力集中，利用莫尔-库仑屈服准则，判断土洞洞壁土体是否产生塑性破坏。当按《建筑地基基础设计规范》GB 50007-2002第5.2.5条计算地基承载力时，还应同时确保土洞周围的土体不产生塑性破坏并得到基底容许压力P值，取fa和P的较小值，即为岩溶区土洞地基的地基承载力。
研究结果：推求得到了土洞地基的地基承载力计算方法和计算公式。
研究结论：通过计算分析发现，地下水对地基承载力影响很大，地下水位下降，将降低地基承载力；地基中土洞内存在有充填物，且充满整个土洞时，地基的承载力大大提高。
Research purposes: The subgrade bearing capacity for soil cave is determined reasonably in karst region.
Research methods: Based on the elastic and plastic theory, the stress distribution of soil cave in foundation can be deduced in karst region. With the action of self-weight stress of soil mass and additional contact pressure, the stress concentration will be taken place in soil mass around soil cave periphery. By the Mohr-Coulomb yield criteria, whether the soil mass around soil cave is destroyed can be determined. When subgrade bearing capacity is calculated according to the item 5.2.5 of “Code for design of building foundation" GB 50007-2002, it should assured simultaneously that the soil mass around soil cave cannot be had the plastic failure, and the P value of contact allowable pressure can be obtained, the less value between fa and P is the subgrade bearing capacity for soil cave.
Research results: The calculation formula for subgrade bearing capacity of soil cave has been deduced.
Research conclusions: Through analysis and calculation, this paper points out that the groundwater has great influence on subgrade bearing capacity，and the bearing capacity will be decreased with the decline of groundwater; The bearing capacity will be increased greatly when soil cave is filled full with some materials.
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