某邻近地铁隧道深基坑施工监测分析  

Field Observation of a Deep Excavation Adjacent to Subway Tunnels

作　　者：丁勇春[1] 戴斌[2] 王建华[1] 徐中华[2] 

机构地区：[1]上海交通大学土木工程系,上海200030 [2]华东建筑设计研究院有限公司,上海200002

出　　处：《北京工业大学学报》2008年第5期492-497,共6页Journal of Beijing University of Technology

基　　金：上海科学技术委员会资助项目(0401212001);上海市科委科技攻关资助项目(052112010)．

摘　　要：基坑开挖中的土体卸荷效应会引起支护结构及周围地层的变位,从而对周边环境产生不利影响.对某邻近地铁区间隧道的深基坑施工进行了全过程跟踪监测,及时反映不同工况下基坑围护结构变形、支撑轴力及立柱回弹的变化特征,分析了基坑施工对周边环境特别是对邻近地铁隧道的影响.监测结果表明:围护结构的变形增量主要发生在基坑深层土体开挖阶段,开挖至坑底后变形趋于稳定;围护结构变形与支撑轴力具有关联性,围护结构的侧向变形越大,相应位置支撑的轴力也越大;坑底土体卸荷隆起带动立柱回弹,基坑中部回弹较大,基坑边角和施工栈桥附近回弹较小;开挖卸荷引起基坑附近一定范围内地表沉降和深层土体隆起,带动相邻地铁隧道上抬;基坑施工对邻近地铁隧道竖向变形的影响比对水平变形的影响更明显.Unloading effects of deep excavation will inevitably cause deformation and movement of retaining structures and adjacent ground, thus exert negative impact upon surrounding environment. An in-situ monitoring programme was carried out for a deep excavation adjacent to the existing subway tunnels during the whole process of construction and the observation results were presented and discussed in detail. It is found that substantial displacements of the retaining structures occur during the final stages of the excavation. The maximum displacement of the retaining structures appears between the second and the third level of the horizontal struts, which correspondingly induces high values of axial forces in these two levels of the struts. Unloading due to the excavation leads to the uplift of the vertical props inside the excavation. The magnitude of the uplift near the center of the pit is greater than those near the side and the comers. The excavation leads to the ground settlement and deep-level strata heave near the excavation and consequently the uplift of the subway tunnels. The influence of the deep excavation on the vertical deformation of the subway tunnels is much more significant than that on the horizontal deformation.

关 键 词：基坑 施工 钢筋混凝土 地下连续墙 监测 变形 

分 类 号：TU473.2[建筑科学—结构工程]