基于监测数据对基坑工程变形规律分析

Analysis on Deformation of Foundation Pit Engineering Based on Monitoring Data

目的为解决基坑开挖时结构的安全与稳定问题,对基坑工程的变形进行分析,找出影响规律.方法以营口某深基坑工程实例为研究背景,整理现场得到的桩顶位移、地表沉降及深层土体水平位移等监测数据,对基坑工程的支护结构和周围土体及墙后土体在施工过程中产生的位移变化进行分析.结果支护结构相同的挡墙坑角处变形最小,中间位置变形最大,并且基坑变形随着开挖深度的增加而变大.开挖深度较大的软土地区基坑周边深层土体水平位移曲线类型大致表现为抛物线形,其最大水平位移大致为（2.0~10.0）×10-4hd,通常发生在基坑工程底部附近.结论深基坑工程的支护结构顶部水平位移与竖向位移变化趋势一致,表明二者的产生条件和影响因素大致相同.坑底部下面土体的水平位移对于坑底隆起有着直接影响,支护结构的强度越低,坑底部隆起的增强区域的范围也越大.

In order to solve the problem of safety and stability of foundation pit excavation, deformation of the foundation pit is analyzed, and the influence law is found out. Taking a deep foun- dation pit engineering in Yingkou as a research background, monitoring data for pile top displacement, surface subsidence and the horizontal displacement of deep soil were obtained. Displacements of the branch support structure and surrounding soil were analyzed. It is found that the deformation at the bottom comer is minimum. The maximum deformation is at the middle position. With the increase of the excavation depth, the foundation pit deformation increases. In soft soil area, when the excavation depth is large, the deep soil horizontal displacement curve of the foundation pit has a type of parabola,the maximum horizontal displacement is about （2. 0 - 10.0） × 10-4hd, which usually occurs near the bottom of the foundation pit. The horizontal displacement variation is similar as the vertical displacement variation on the top of the supporting structure. Conclusion is that the horizontal displacement on the bottom surface of foundation pit has a direct influence on the bottom uplift of foundation pit. Strength of the supporting structure of foundation pit is lower, the pit bottom uplift enhancement range is also larger.