竖向荷载下桩筏基础通用分析方法

General analysis method of piled raft foundation under vertical loading

根据已有的竖向荷载下刚性板桩筏基础分析结果提出了一种竖向荷载下桩筏基础的通用分析方法。桩筏基础分析中考虑了4种相互作用,分别为桩–土–桩、桩–土–板、板–土–桩和板–土–板相互作用。筏板分析采用有限单元方法,以厚薄板通用四边形等参单元进行分析。该方法可以分析由任意桩长、桩半径和刚度特性的桩群以及任意厚度和几何外形的筏板组成的竖向受荷桩筏基础。应用该方法不需要划分桩土体单元,其分析复杂程度基本等同于弹性地基板基础,且分析过程简洁。通过与各种方法的比较证明该方法是合理可行的,精度上也满足要求。

A general analysis method of piled raft foundation under vertical loading was presented based on the results of piled raft foundation with rigid cap under the same loading condition. Four types of intreraction could be considered herein, i.e., pile-soil-pile interaction, pile-soil-plate interaction, plate-soil-pile interaction and plate-soil-plate interaction. Cap of foundation was analyzed through finite element method with a rational approach to formulate Reissner-Mindlin quadrilateral element. It was mentioned that pile group could be comprised of piles with various lengths, radiis and stiffness modulis. Raft with any shape and depth could be studied accurately. The method did not involve the discretization of the soil or piles and it could be used to analyze piled raft foundation as simply as to analyze raft foundation. By comparison with the results of other methods, it was shown that the proposed method was reasonable and feasible.