复杂环境下北京地铁车站深基坑变形时空规律研究  

Research on spatio-temporal law of deep excavation deformation under complicated environment in Beijing Subway Station

作　　者：李淑 张顶立[2] 邵运达[1] LI Shu;ZHANG Dingli;SHAO Yunda(School of Engineering,The Open University of China,Beiing 100039,China;Key Laboratory of Urban Underground Engineering of Ministry of Education,Beiing Jiaotong University,Beijing 100044,China)

机构地区：[1]国家开放大学理工教学部,北京100039 [2]北京交通大学城市地下工程教育部重点实验室,北京100044

出　　处：《北京交通大学学报》2019年第4期29-36,共8页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：国家重点研发计划(2017YFC0805401);城市地下工程教育部重点实验室开放研究基金(TUE2018-03);国家开放大学“十三五”规划青年基金(G18F0031Q)~~

摘　　要：以北京地铁9号线丰台北路站深基坑及周围环境的变形监测数据为依据,探讨了地表沉降、桩体位移、支撑轴力与坑底隆起的时空规律.研究表明:1)地表沉降和桩体侧移随时间发展逐渐变大;空间上沿坑角至基坑中部逐渐增大,大致可分为3个区域:快速增长区域、过渡区域和平缓区域;相比地表沉降,桩体的侧移量更大一些,桩体侧移在开挖到底后的拆撑过程中有明显增大.2)由于基坑土方开挖和支撑架设的反复扰动,支撑轴力反复振荡,直至底板施工完成时逐渐趋于稳定;空间上沿坑角至基坑中部逐渐增大;同一根桩轴力大小与桩体侧移具有显著的负相关性,侧移随支撑轴力的增大而减小.3)坑底隆起随时间发展逐渐增大,至开挖结束时达到最大,然后逐渐减小;空间上基坑中部(中间桩)隆起量远大于坑边(围护桩),差异量随开挖深度增大逐渐增大,至开挖结束时达到最大.研究成果可为北京地区深基坑精细化设计与施工提供参考.Field observations of performance in deep excavation of Fengtai Road Station Line 9 are used to analyze spatio-temporal patterns of ground settlement,lateral displacement,axial force of struts,and basal heave,and influences on infrastructures.Research shows that:1)Ground surface settlement and lateral displacement gradually increase as excavation proceeds.Values increase away from the corner and achieve to the maximum at midspan of long side,there are three regions roughly:rapid growth region,transition region and stable region.The magnitude of lateral displacement shows little larger than settlement,which have an additional increase as struts removal.2)The axial force oscillates repeatedly as excavation proceeds and struts installed,and changes negligibly till mat foundation constructed.The axial force increases away from the corner along with the long side.A significant negative relationship exists between axial force and lateral displacement of a pile,lateral displacement decreases with the axial force increase.3)As excavation proceeds,basal heave gradually increases,and achieves to the maximum after excavation reaching the final grade,then a reversal trend appears.The upheaval in centre(intermediate pile)is much larger than that observed at edge(retaining pile),upheaval difference increases with excavation depth and reach its maximum when excavation finished.Results can provide references for construction and design of deep excavation in Beijing.

关 键 词：深基坑 复杂环境 变形 时空规律 

分 类 号：TU478[建筑科学—结构工程]