深挖填土基坑监测及安全性分析

Monitoring and security analysis of deep pits

为研究填土基坑破坏机理,分析沉降监测及水平位移监测中基坑变形与基坑设计、施工速度、施工质量、周围建筑及水文地质情况的相互关系,采用变形观测仪器,测试了一典型基坑不同位置监测点处的变形速率、变形量及绝对变形量等量值,理论上验算了土性参数并分析了基坑在各工况下的安全系数。结果表明基坑顶部变形在开挖过程中存有方向相反的反复过程,形成不同的局部破坏形态;是否合理选取填土层物理力学参数、超载、施工中水环境的变化及基坑支护的设计都影响着基坑边坡的安全。本基坑工程引发的问题对同类型基坑有普遍性。

Based on damage of the foundation pits in Nanning, the connections between pit deformation and the main factors, such as foundation design, construction speed, construction quality, sur- rounding buildings and hydro-geological conditions were discussed. According to the deformation rate, the amount of deformation and the absolute amount of deformation in different monitoring sites, a repeated process of the deformation at the top of the foundation pit which had significant influence on local damage was found. By calculating the soil parameters and studying the safety factors of pit under various service conditions in theory, the importance of correct selection of soil physical parameters and the influence of overload on soil nailing design of pits were shown. Result in this paper are universality for the same deep pit in filling as Nanning＇s.