寒区土岩复合地层地铁车站基坑支护结构变形及优化研究

Research on Deformation and Optimization of Foundation Pit Supporting Structure of Metro Station in Soil and Rock Composite Stratum in Cold Region

为解决寒区土岩复合地层下的地铁基坑支护优化问题,节约社会资源,论文依托具有该种地层的乌鲁木齐二道桥地铁车站,建立了基坑开挖有限元模型,分析了开挖过程中基坑周围的地表沉降和围护结构位移的变化规律。根据经过验证的模型,调整钢支撑的位置和支撑材料的组合,在保证安全性的基础上,优化了基坑支护结构的设计。将中部钢支撑位置向下移动10.4%的基坑深度,使支撑最大轴力降低了19.3%;将中部钢支撑替换为混凝土支撑对改善基坑周围土体沉降最优,沉降最大值降低了44%。

In order to solve the optimization problem of subway foundation pit support under the soil-rock composite strata in cold areas,and save social resources.In this paper,a finite element model of foundation pit excavation is established based on the Erdaoqiao Metro Station in Urumqi with this kind of strata.The change law of the ground settlement around the foundation pit and the displacement of the retaining structure during the excavation process is analyzed.Relying on the verified model,the position of the steel support and the combination of support materials were adjusted,and the design of the foundation pit support structure was optimized on the basis of ensuring safety.Moving the central steel support position down by 10.4% of the depth of the foundation pit reduces the maximum axial force of the support by 19.3%;replacing the central steel support with concrete supports is the best way to improve the settlement of the soil around the foundation pit,and the maximum settlement is reduced by 44 %.