软土地层中深基坑SMW工法施工数值分析

考虑某市妇女活动中心大楼地质条件及周边环境特点,通过方案优选提出了基坑SMW工法的施工方案;基于有限差分理论,采用FLAC3D计算软件对基坑不同开挖工况下基坑坑底回弹、基坑周围地表沉降、钢支撑内力及SMW围护结构的侧移变形进行了模拟计算,结果表明:基坑开挖过程中坑底出现明显的回弹变形,基坑周边由于地表附加荷载的影响出现一定的沉降,支护墙侧向水平位移随开挖深度的增加而增大,布设横向钢支撑后墙体的侧移得到有效控制,钢支撑轴力随开挖深度的增大而增大。采用SMW工法进行施工,坑底回弹变形、支护结构内力及支护墙侧移量都在安全控制范围以内,由此表明采用SMW工法进行支护设计是合理可靠的。

Numerical Analysis on the Soil Mixing Wall Working Method of Deep Foundation Pit in Soft Soil Stratum

The SMW method for the foundation pit of a Women’s Activity Center Building is proposed after analyzing the geological conditions and its surrounding environment.Based on the finite difference theory,the springback deformation and surface subsidence around the foundation pit,inner force of the steel supports and the lateral displacement of the parapet wall in different working conditions are calculated by the FLAC3D.It is found that the significant springback deformation appears at the bottom of the foundation pit,and the large ground subsidence around the foundation pit is caused by the surface additional loads.With the growth of excavation depth,both the horizontal displacement of the parapet wall and the axial force of the steel support are increased,and the horizontal displacement of the parapet wall is controlled effectively after laying the horizontal steel support.With the SMW method,the springback deformation,inter force of the steel support and horizontal displacement of the parapet wall are controlled in a safe range,which shows that the SMW method is reasonable and reliable to the support design.