深基坑支护结构—土非线性共同作用弹性地基反力法

An elastic subgrade reaction method considering nonlinear interaction between protection-structure and soil for deep excavations

为使深基坑支护设计考虑支护结构-土的非线性共同作用,将地基土的水平基床系数视为深度和围护墙位移的非线性函数,建立作用于围护墙上的土压力增量的计算模型。进而根据一般弹性地基梁的挠曲微分方程,推导出考虑非线性共同作用的弹性地基梁的挠曲微分方程,并在分析深基坑开挖与回筑全过程中各工况支护结构的受力与变形特征的基础上,给出非线性共同作用弹性地基反力法的计算模型与求解方法。工程算例表明,该方法比现行规程设计方法得到的围护墙计算位移更接近实测位移,且计算参数的确定更为方便,具有较强的实用性。

To consider the nonlinear interaction between soil and the protection-structure for deep excavation designs, the horizontal foundation coefficient of soil is taken as a nonlinear function of the depth and the wall deflection. In this connection a mathematical model is established for calculating the earth pressure increment on the wall. The differential equation of the elastic subgrade beam to consider the nonlinear interaction is derived based on the equation of the general elastic subgrade beam. A computer model is presented to calculate the loading and deformation features of the protection-structure during different construction stages. The calculation results indicate that the wall displacements calculated by this method are closer to the actual displacements than those by using the method suggested in the design code, and the calculation parameters can be obtained in a more convenient manner.