摘要：
To provide a calculation method for the ultimate bearing capacity at the tip of a single rock-socketed pile in different stratum with karst cave.Firstly,a simplified calculation model was establishedab on the basis of bearing characteristics of a rock-socketed pile in Karst area.Secondly,the bearing mechanism at the tip of a rock-socketed pile in Karst area was analyzed and the calculation model of ultimate bearing capacity was built as well.Thirdly,average constraint stress at the tip of a rock-socketed pile in Karst area was solved by using the method of complex variable function,and therefore,the ultimate baring capacity at the tip of a rock-socketed pile in Karst area was obtained.Then,the influencing factors of ultimate bearing capacity at the tip of a rock-socketed pile in Karst area were analyzed,and the analysis results show that increasing the cavity radius,increasing the cavity depth or decreasing the distance from the pile tip to the center of cavity may increase the impact on ultimate bearing capacity at the tip of a rock-socketed pile in Karst area.At last,theoretical results based on an engineering example disclose that the proposed method can meet the requirements of practical projects.It is noteworthy that due to the assumptions,the validity of calculation results in this work is only applicable to the case that the distance between the cave and pile tip is larger than 3 times the pile diameter.%为了给出嵌岩桩作用在含不同溶洞地层上的桩端极限承载力计算方法,首先,根据岩溶区桩基承载特性建立了简化计算模型;其次,分析了岩溶区嵌岩桩桩端承载机理,并提出了岩溶区嵌岩桩桩端极限承载力计算模型;再次,利用复变函数的方法对岩溶区嵌岩桩桩端平均约束应力进行求解,进而求得岩溶区嵌岩桩桩端极限承载力;然后,对岩溶区嵌岩桩桩端极限承载力的影响因素进行了参数分析,结果表明:①溶洞半径越大,对桩端极限承载力的影响越大.②桩端到溶洞中心的距离越大,对桩端极限承载力的影响越小.③溶洞埋深越大,对桩端极限承载力的影响越大.最后,工程算例对比分析表明该方法能满足工程要求,能为岩溶区嵌岩桩工程实践提供一些参考价值.值得注意的是,由于假定条件的限制,本文计算结果仅适用于溶洞洞边与桩端距离大于3倍桩径时的情形.
