基于有限差分法的基坑围护结构变形分析

Analysis of Pit Support Structure Deformation Based on Finite Difference Method

针对基坑开挖过程围护结构变形稳定性问题,基于有限差分数值方法,以合肥地铁大东门车站为研究对象,分析了基坑开挖过程中深基坑土体和围护结构的内力及变形情况.研究表明:随着深度的加大,地下连续墙围护结构水平变形不断增大,墙体向基坑内不断发展变形,形态上呈凸肚状;基坑开挖过程中最大主应力和最大主应力差均在围护结构上,最大剪应力和塑性区主要分布在基坑的底部和周边地表;基坑交界处的桩轴力较大,并且轴力变化曲线呈折线形.

Urban subway construction is now pretty popular in our country.The scale of transfer station ex-pands and the depth of the pit increases. Therefore, the analysis of the stability of the pot support structure deformation during the deep excavation engineering is of great significance. Based on the Hefei Metro Da dongmen station,the numerical analysis method based on finite difference method is used to study the de-formation characteristics and the internal force variation of surrounding soil and supporting structure. The research shows that with the increase of the depth, the horizontal deformation of diaphragm wall retaining structure increases, the deformation of the wall crossing to the foundation pit develops, and its deformation form shows a convex shape; the maximum principal stress and maximum principal stress difference appear around the retaining structure during excavation, and the shear stress and plastic zone distribute over the bottom and surrounding surface of excavation; the piles,axial force is greater than that at the junction of two foundation pits, and the variation curves show a broken line form.