考虑基坑坑内反压土作用的实用方法及应用

A Practical Method and Engineering Application Considering the Effect of Earth Berm in Foundation Pits

基坑坑内反压土可有效减小支护结构的内力、变形与嵌固深度,具有较好的经济效益,但是目前的基坑支护设计规范均未涉及反压土的设计计算方法,且目前工程界对此问题的研究尚没有形成统一的算法,设计人员多是凭经验设计。为了定量分析反压土的作用效果,基于理论力学中加减平衡力系的原理,提出了一种新的简化实用方法,即在支护结构的水平方向减去一个平衡力系来考虑反压土的作用。通过一个工程实例,将该实用方法的计算结果与有限元计算的结果进行了对比,初步验证了该方法的可行性和可操作性。该方法可为工程设计人员设计时参考和推广使用。

The earth berm in the foundation pit can effectively reduce the internal force,deformation and embedded depth of the supporting structure,and has good economic benefits.However,the current design specifications of the foundation pit support do not involve the design and calculation method of earth berm.At present,the engineering community has not formed a unified algorithm for this issue.Designers usually design it by experience.In order to quantitatively analyze the effect of earth berm,we propose a new simplified practical method based on the principle of addition and subtraction of the equilibrium force system in theoretical mechanics.It is to subtract an equilibrium force system in the horizontal direction of the support structure to consider the effect of earth berm.Through an engineering example,the calculation results of the practical method are compared with the results of the finite element calculation,and the feasibility and operability of the method are preliminarily verified.This method can be referenced and promoted for engineering design personnel.