中文摘要：

结合岩溶区某桥梁基桩优化设计实例,提出针对基础下并非所有基桩桩端都存在溶洞的情况,通过合理设计承台梁和各桩桩径的方式来减小桩端存在溶洞基桩的桩顶分配荷载,尽量将该类基桩奠基标高设置在最上层顶板上,达到减小岩溶区桩基工程处治难度的方法。在此基础上,根据桩端下存在与不存在溶洞基桩刚度的差异,在分析溶洞顶板沉降计算方法后,解决了差异地基上桩基承台梁内力计算问题。将该方法应用于工程实例中,在分析承台梁刚度和桩径对基桩桩顶荷载分配的影响后,对该桩基础进行优化设计并取得了良好效果。

英文摘要：

With respect to the fact that the piles of bridge pile foundation which located on the roof of caves possessed beating capacity of much less magnitude than that without underlying caves, combined with a optimization design example for a bridge pile in karst region, a technique of designing rationally cap beam and pile diameter was proposed to decrease the distributed load of pile above caves, and guarantee the elevation of pile end settled on the first roof of cave to the largest extent. Further jobs were dedicated into the computational issues encountered in the optimization process, especially the internal force calculation of cap beam on the differential ground by analyzing the settlement computing methods of cave roof considering the discrepancy of pile stiffness for pile end with and without underlying cave. This approach was used in a practical case to conduct the optimization design of pile foundation by taking the influence of stiffness of cap beam and pile diameter on the load distribution of pile top into account with a good effect.