北京地铁地连墙基坑变形规律研究

为研究北京地铁地连墙基坑受力变形特征，采用统计法对近5年期间北京在施地铁基坑变形监测数据进行整理分析，并按照围护结构厚度及支撑体系类型对地连墙基坑进行分类，得出不同类型基坑地表、墙体、格构柱的变形规律以及基坑沉降槽曲线，提出地表隆起及墙体变形的新模式。结果表明：1)基坑监测范围内的地表变形中，地表隆起占比高达20%～45%，支撑体系类别及围护结构厚度不同对地表隆起比例与最大变形范围存在不同影响；2)根据墙顶变形方向及幅度，将墙体变形分为4种类型，开挖深度对墙体变形量的影响要大于围护结构厚度对土体变形的约束作用；3)墙顶的变形规律以上浮为主，占统计数据的90%以上；4)格构柱同样以隆起为主，大于墙顶隆起。

Deformation Law of Foundation Pit Connecting Beijing Subway and Ground

To investigate the stress and deformation characteristics of the diaphragm wall foundation pit in the Beijing subway, a statistical method was employed to analyze the monitoring data from the past five years, focusing on the foundation pit deformation of the Beijing subway diaphragm wall. The foundation pits were classified according to the thickness of the enclosure structure and type of support system. The deformation patterns of different types of foundation pit surfaces, walls, and lattice columns, as well as the curve of the foundation pit settlement groove, were determined. Additionally, a new model for surface uplift and wall deformation was proposed. The results show that 1) within the monitoring range of the foundation pit, the surface uplift accounts for 20%~45% of the deformation. Different types of support systems and thicknesses of the enclosure structure have varying impacts on the proportion of surface uplift and the maximum deformation range. 2) Wall deformation can be classified into four types based on the direction and amplitude of the wall top deformation. The influence of excavation depth on wall deformation is greater than that of the increased thickness of the enclosure structure. 3) The primary deformation pattern of the wall top is upward, comprising over 90% of the statistical data. 4) Lattice column deformation is also predominantly uplift, which is more significant than the uplift of the wall top.