考虑相互作用的桩筏基础简化分析法

提出了一种考虑土 -桩 -筏相互作用的桩筏基础简化分析法。将群桩中每根桩的桩顶沉降分成桩身压缩和桩端沉降分别计算 ,桩身压缩由单桩静载荷试验或其他方法估算 ,桩端沉降根据分层总和法计算。将桩简化成弹簧作用在筏板下 ,弹簧刚度根据桩顶平均荷载和相应的沉降获得。采用 16节点退化实体等参元对筏板进行有限元分析 ,获得筏板的沉降和内力等。本文方法桩的刚度计算相对简单 ,可以考虑成层地基、地基层厚不均匀等情况 ,沉降计算方法和土性参数确定基本上与“规范”法相同 ,板单元特别适合于平面形状不规则及变厚度的筏板分析。最后 ,将本文的计算结果和其他方法作了对比 ,并介绍了该方法的工程应用。

A simplified method to analyze soil-pile-raft interactions

The paper describes a simplified method to analyze soil-pile-raft inte ractions. The settlement of each pile in pile group consists of the compression of the pile and the settlement of the pile toe. The compression of pile can be d etermined by static load test or estimated by Geddes' method. The settleme nt of pile toe is calculated by layerwise summation method. The stiffness of each pile in pile group is determined by the average of loads acting on piles and the settlement of the pile top. Then the pile is modeled as a elastic spring with t he stiffness of the corresponding pile. The raft is modeled by the Finite Elemen t Method (FEM) with 16-node degenerated elements, to obtain its internal fo rc e and deformation.These elements are particularly suitable to model the raft wit h i rregular thickness and shape. Compared with other methods, the proposed me thod is rather easy and simple to estimate the pile stiffness and to model layered so ils. Its results are more reasonable than those obtained by other methods.At th e end of the paper, a case record is presented to show the effectiveness of this method.