某地铁深基坑顺逆结合开挖变形性状的实测分析  

Measured Performance of a Semi-top-down Deep Foundation Excavation for a Subway Station

作　　者：杨鹭[1] 李裘鹏 江建洪[1] 马健[2] YANG Lu LI Qiupeng JIANG Jianhong MA Jian(School of Urban Rail Transportation,Soochow University,Suzhou,Jiangsu 215131 ,China Shanghai Geotechnical Investigations ＆ Design Institute Co. , Ltd. , Shanghai 200032, China)

机构地区：[1]苏州大学城市轨道交通学院,江苏苏州215131 [2]上海岩土工程勘察设计研究院有限公司,上海200032

出　　处：《施工技术》2017年第16期95-100,共6页Construction Technology

基　　金：国家自然科学基金项目(51308364)

摘　　要：目前对于软土地区采用顺逆结合法开挖的深基坑变形性状研究还较少。研究了杭州某34.5m深的地铁基坑在顺逆结合开挖方法下的变形性状,分析了基坑开挖对一倍开挖深度距离内邻近地铁隧道附近土体的影响。研究结果表明:(1)逆作板加强了围护结构体系的刚度,有效地限制了地下连续墙的侧移、墙后地表沉降和立柱隆起,进而限制了邻近隧道附近土体的位移;(2)合理的土体开挖顺序能有效地限制基坑中间处的墙体侧移,使得该截面的墙体侧移并非是沿基坑长边所有截面中墙体侧移最大的;(3)隧道与附近土体相互作用明显,附近土体在隧道埋深处都随刚度相对较大的隧道向基坑内呈现一定程度的水平移动,而上部土体的水平移动随着空间位置的不同而表现各异。相关结论对软土地区类似深基坑工程的变形控制具有一定的参考意义。Research on deformation behavior of semi-top-down deep foundation excavations in soft clays is still not much. Measured performance of a 34. 5m deep semi-top-down excavation for a subway station in Hangzhou was studied,and the influence of excavation on surrounding soil of a tunnel nearby within the distance of one time the excavation depth was analyzed. Based on the analyses of field data,the following findings were obtained：（1）the floor slab reinforced the stiffness of the supporting system and effectively suppressed the diaphragm wall deflections,ground settlement behind wall and uplifts of interior columns and further suppressed the displacement of soil surrounding the tunnel nearby;（2）reasonable excavation order can effectively suppress the wall deflections of the middle section of the long side of the excavation and make the maximum wall deflection of the middle section not the maximum among those of all section along the long side;（3） there are strong interactions between the tunnel and its surrounding soil. The surrounding soil at the depth of the tunnel move towards the excavation with certain degree of horizontal magnitude together with the relatively stiff tunnel while the soil in the top layers move in different ways depending on their different locations. The related findings may be meaningful for the displacement control of similar deep foundation excavations in soft soil.

关 键 词：地铁 深基坑 软土 顺逆结合法 变形性状 分析 

分 类 号：U45[建筑科学—桥梁与隧道工程]