一种实用的桩-筏-土非线性共同作用分析方法

A Practical Nonlinear Analysis Method for Interaction of Pile-Raft-Soil

提出了一种实用的考虑上部结构影响的桩-筏-土非线性共同作用分析方法:用薄厚板通用矩形单元建立筏板刚度矩阵.用分层地基模型,建立地基柔度矩阵和刚度矩阵,通过调整土的压缩模量近似模拟土的非线性.针对层状地基中桩与桩、桩与土相互作用的内在机制,用剪切位移法和递推原理导出桩顶柔度系数的计算公式,建立桩土支撑体系柔度矩阵的近似解析公式,获得桩土支撑体系刚度矩阵.上部结构用子结构方法分析,将刚度和荷载向筏板中性面凝聚.最后用该文给出的耦合方法,将上部结构、桩土支撑体系和筏板的刚度矩阵进行耦合,建立共同作用方程.利用该方程可方便地进行桩筏基础桩顶反力及筏板位移特性研究,具有较好的实用性.

A practical nonlinear analysis method for the interaction of the pile-raft-soil considering the influence of the upper structures is proposed in the paper.The stiffness matrix of the raft is formulated using the generalized rectangle element for the thin-thick slab.The flexibility matrix and the stiffness matrix of the layered foundation are formulated using the layered soil model,and the nonlinear characteristics of the layered soil are approximately simulated by adjusting the compression modulus of the soil.Based on the inherent mechanism of the interaction of the pile-pile and the pile-soil in the layered soil,the calculation formula of the flexibility coefficient of the pile head are derived using the shear displacement method and the deductive theory,and the approximately analytical formula of the flexibility matrix of the pile-soil supported system is created,thus the stiffness matrix of the pile-soil supported system is obtained.The upper structure is analyzed by means of the substructure method;meanwhile,the stiffness and load of the upper structure are condensed to the neutral plane of the raft.Finally,used the coupling method presented in this paper and coupled the stiffness matrixes of the superstructure,the pile-soil supported system and the raft together,the interaction equation is formulated.This interaction equation has good practicality and can be conveniently applied to analysis and study the characteristics of the counterforce on the pile head and the displacement of the raft of the pile-raft foundation.