以混合支撑体系内力与变形的变化规律为研究目标,以某明挖隧道深基坑为例,采用现场监测方法,对基坑开挖引起的围护结构位移、锚索应力、支撑轴力的变化规律及施工中遇到的一些问题进行了分析.试验表明:开挖至基底标高时,桩顶和桩身位移达到最大值,桩身最大位移发生在基坑中上部6 m处;随着基坑的开挖,锚索应力呈波浪上升状变化,温度和施工荷载是造成波浪状变化的原因;围护结构位移、锚索应力、支撑轴力与开挖深度具有同步性.监测数据整体稳定,基坑采用的混合支撑方案安全可靠.
Take the variation law of internal force and deformation of mixed-supporting system for research target, base on some deep foundation pit dug by Open Cut Method, by the method of field monitoring, the displacement.anchor stress .supporting axial force of the supporting structure and some problems occurred during the construction are analyzed. The main conclusions in this thesis have been summarized as follows: a) the displacement of pile top and pile body reached to the maximum when dug to the bottom of foundation pit. The maximum displacement occurred at the position of 6m- upper part of foundation pile; b) With the excavation of foundation pit, the cable stress rise in wave-like change, the temperature and construction loads is the reason for cable stress showed wavy change; c) the displacement, anchor stress, supporting axial force of envelope have obvious synchronization with the depth of excavation, monitoring data is stable overall, the mixed-supporting structure for the deep foundation pit is secure.