深厚软土地层地下车站端头井深开挖施工与数值模拟

Construction and Numerical Simulation of Deep Excavation of End Shaft of Underground Station in Deep Soft Soil Layer

摘要: 深厚软土地区土体承载力低，易产生触变性，引起周边土体不均匀沉降。为研究深厚软土地层地下车站端头井深开挖周边土体的位移特征及围护结构的受力变形特性，运用MidasGTSNX计算软件，对软土地层某地铁深基坑施工过程进行建模分析。结果表明，在开挖的过程中，地表沉降随着开挖进行会越来越大，沉降最大位置出现在端头井距端头井边界0.5倍的端头井宽度处，沉降影响范围为端头井宽度两倍处；随着开挖的进行，地连墙侧向位移也会不断变大，最大位移处在开挖面附近；除了第一道支撑外，其余支撑轴力值在开挖至坑底时达到最大。

Abstract: The bearing capacity of soil in deep soft soil area is low, which is easy to produce thixotropy, resulting in uneven settlement of surrounding soil. In order to study the displacement characteristics of the soil around the deep excavation of the end well of the underground station in the deep soft soil layer and the stress and deformation characteristics of the retaining structure, the construction process of a subway deep foundation pit in the soft soil layer is modeled and analyzed by using Midas GTS NX calculation software. The results show that in the process of excavation, the surface settlement will increase with the progress of excavation. The maximum settlement occurs at the width of the end well 0.5 times from the end well to the end well boundary, and the influence range of settlement is twice the width of the end well; with the progress of excavation, the horizontal displacement of the diaphragm wall will continue to increase, and the maximum displacement is near the excavation surface; except for the first support, the axial force of other supports reaches the maximum when they are excavated to the bottom of the pit.