温州市域铁路明挖深基坑施工变形规律实测研究

Measured Deformation Characteristic of Open Excavation Deep Foundation Pit in Suburb Railway of Wenzhou

软土城市地区,轨道交通明挖深基坑开挖引起的变形效应是工程建设过程中的一项重要控制内容。本文依托温州市域铁路某标段明挖深基坑工程,基于现场实测,分析了深基坑施工影响效应的地表沉降、立柱轴力、土体和墙体水平位移等因素。分析结果表明:地表沉降变形在深基坑开挖后开始加速,至底板混凝土浇筑完成后,地表沉降速率开始减缓,但累计沉降依然在增大。在深基坑开始开挖的一个月之内,土体深层水平位移变化非常明显,随开挖深度逐渐增大,在深度为13 m附近达到最大值,随后土体深层水平位移随深度的增加而减小;连续墙墙体的水平位移变化趋势基本上与土体深层水平位移一致;深基坑周边建筑物在基坑施工初期沉降较小,后期距离深基坑位置越近,建筑物累计沉降越大。

In the soft soil urban area,the deformation effect caused by open-cut deep foundation pit of rail transit is an important control content in the process of engineering construction.Based on the open excavation deep foundation pit project of a railway in Wenzhou area,this paper analyzed the factors such as surface settlement,axial force of column, horizontal displacement of soil and wail by the field measurement.The results show that the deformation of surface subsidence accelerates after the excavation of deep foundation pit,and the rate of ground subsidence begins to slow down,but the accumulative settlement is still increasing.Within one month of deep foundation pit excavation,the horizontal displacement of deep soil is very obvious and begins to change with the excavation depth.The depth of the soil reaches the maximum near the depth of 13 meters,and then the horizontal displacement of the deep soil decreases with the increase of depth.The variation trend of horizontal displacement of continuous wall is basically consistent with the horizontal displacement of deep soil.The settlement of the surrounding buildings in the deep foundation pit is small in the initial stage of foundation pit construction.The closer the building is to the deep foundation pit in the later stage,the greater the cumulative settlement of the building is.