地铁基坑开挖变形特征研究

Study on Deformation Characteristics of Metro Foundation Pit Excavation

摘要: 本文以某滨海城市的地铁车站延长线基坑工程为背景，通过监测数据结合数值模拟，采用Midas GTS NX有限元软件对超长基坑进行深入研究，分析了基坑连续墙变形过大以及基坑事故发生原因。研究了基坑在开挖过程中地面沉降主要影响区域；找出同侧地连墙体水平位移差异的原因是深厚淤泥层是主要因素；通过采用传统条分法与有限元极限平衡法计算结果边坡安全(稳定)的规律；淤泥土质的边坡影响因素敏感性大小的参数；最后通过对某基坑施工过程监测数据及数值计算验证了事故基坑土体滑塌成因是坡角过大、局部超载、土体超挖。

Abstract: Based on the foundation pit project of subway station extension line in a coastal city, this paper deeply studies the super long foundation pit by using Midas GTS NX finite element software through monitoring data and numerical simulation, and analyzes the causes of excessive deformation of diaphragm wall and foundation pit accidents. The main influence area of ground settlement during foundation pit excavation. It is found that the reason for the horizontal displacement difference of the ground connecting wall on the same side is that the deep silt layer is the main factor. The law of slope safety (stability) is calculated by using the traditional slice method and finite element limit equilibrium method. The parameters of sensitivity of influencing factors of silt soil slope. Finally, through the monitoring data and numerical calculation of a foundation pit construction process, it is verified that the causes of soil collapse of the accident foundation pit are excessive slope angle, local overload and soil overbreak.