复杂地质旋流池内衬墙分层逆作效用分析

Study on the Effect of the Top-Down Construction of Interior Wall during Swirling Pool Excavation

武汉鄂钢旋流沉淀池深36.5m,直径26m,在其基坑开挖范围内同时存在土层和岩层,采用地下连续墙结合分层逆作的内衬墙作为基坑围护结构,地下连续墙仅在土层中设置,而内衬墙分六层逆作在土层和岩层中设置。应用大型通用有限元软件ANSYS对该基坑工程分别模拟了采用内衬墙分层逆作法和不采用内衬墙两种情况下的地下连续墙以及围岩的内力和变形,对比分析了内衬墙分层逆作法在基坑开挖过程中的作用。根据分析结果,内衬墙具有限制地下连续墙和围岩体变形以及减小连续墙环向压应力的作用;内衬墙的作用与地下连续墙的侧向变形有关,当地下连续墙侧向变形较小时,内衬墙的作用有限。基于此,作者提出了对传统内衬墙逆作法施工工法优化的建议。

The Wuhan E-steel factory rotation flow sedimentation tank is an underground structure with a depth of 36.5 meters and a diameter of 26 meters.There are soil layer and rock layer within the depth of the excavation.Continuous diaphragm wall combined with top-down constructed interior wall is used as retaining structure.The interior wall is divided into six segments and constructed in soil layer and rock layer.The continuous diaphragm wall is only constructed in soil layer.The FEM software ANSYS is used to simulate this excavation under two different conditions,with or without top-down construction of interior wall.Stress and displacement of retaining structure and rock were analyzed.Results show that the interior wall restricts the displacement of the continuous diaphragm wall and the envelope rock.Its effectiveness is related to the lateral displacement of the continuous diaphragm wall.If the lateral displacement of the continuous diaphragm wall is relatively low,the effects of the interior wall will be limited.Based on the conclusion,suggestions are given to optimize the construction method.