基于节约理念的带桩筏基设计方法

Design Methods for Piled Raft Foundations Based on the Economic Concept

采用线性扩展Drucker-Prager模型对带桩筏基下的地基土进行弹塑性模拟,建立了带桩筏基系统的ABAQUS程序三维有限元模型.模型中桩和土采用空间8节点实体单元模拟,筏板采用4节点厚板单元模拟,并采用三维有限元-接触面单元相耦合的数值方法来模拟桩-土体系,经分析计算得到了带桩筏基的一些工作特性.在此基础上结合《建筑地基基础设计规范》,改进了复合桩基的设计方法,提出了"三阶段"设计理念,并将其应用于工程实例,证明了两种方法的可行性.实例分析结果表明,复合桩基和"三阶段"设计方法较常规设计方法经济,是一种实用的带桩筏基设计方法.

In this paper, first, the soil under a piled raft foundation was simulated via the linear extended Drucker- Prager elastic-plastic model. Next, behaviors of the piled raft foundation system were revealed by using a 3D finite element model based on the ABAQUS program. Then, the dimensional eight-node solid element, the four-node thick plate element and the 3D finite element coupling interface element were adopted to respectively simulate piles and the soil in the model, the piled raft and the raft-soil system, thus obtaining the operation characteristics of the piled raft foundation. Moreover, the design method of composite pile foundation was investigated and an improved method based on a ＂three-stage＂ concept was presented according to the criterion of ＂Code for Design of Building Foundation＂. The two methods were finally applied to a practical engineering. Results show that, as compared with the conventional design method, the two above-mentioned methods are more feasible, practical and economical.