CSM水泥土墙施工数值模拟及环境影响性分析

Numerical Simulation and Surrounding Influence Analysis of Cement Wall Construction Adopting CSM Method

围护墙施工引发的地层变形在整个基坑施工变形中的占比不容忽视,CSM工法作为一种新型地层改良工法近年来在我国逐步得到推广应用,目前对其成墙施工数值模拟方面还缺乏深入的研究。首先根据CSM施工工艺分析了水泥土墙施工过程中双铣轮下沉注水切削成槽、上提喷浆搅拌成墙、水泥土硬化成墙3个主要施工工序流程的力学演化过程;结合某超深CSM深搅墙试验段项目的现场施工参数,建立对其合理描述的3D弹塑性有限元模型,对软土地层采用了修正剑桥本构模型,对砂性土地层采用了莫尔-库仑模型,分析超深CSM成墙施工对周边地层的变形影响性态;计算结果表明CSM施工的环境影响范围在槽段垂向为1.0倍槽段深度,沿槽段方向为1.5倍槽段深度;分析了泥浆重度γb=12kN/m3、流态水泥土重度γwcs=15kN/m3条件下施工过程中的土压力平衡情况;对不同流态系数下的槽壁稳定性以及周边地层变形量加以讨论。

The displacement due to pit support structure construction should no longer be neglected.As a new soft ground improvement method,CSM method has gotten widely application in recent years,but the numerical simulation about construction mechanic response is still lack of a in-depth research.Firstly,this paper analysis the mechanical process during CSM construction flows;Then a three-dimensional elastoplastic FEM model is established about Shanghai 80 m ultra-deep CSM cement wall testing construction,in which Modified Cam-Clay constitute model is adopted to simulate Shanghai clay,The deformation characteristic of soil layers induced by the CSM construction are investigated;Calculation results indicated that the range of environmental effect is 1.0 time slot depth in perpendicular slot direction and 1.5 time slot depth in parallel slot direction;The soil pressure equilibrium statement is analysis during construction process under the conditionγb=12 kN/m3 andγwcs=15 kN/m3;The slot stability of different viscosity coefficient also been studied detail by detail.