预留土和桩锚结构联合支护下基坑的力学性状  

Mechanical Properties of Foundation Pit Supported by Reserved Soil and Pile-anchor Structure

作　　者：张文举 朱浩延 刘敏 夏冬冬 朱宏伟 Zhang Wenju;Liu Min;Zhu Haoyan;Xia Dongdong;Zhu Hongwei(China Municipal Engineering Southwest Design and Research Institute Co.,LTD,Chengdu 610031,China;Southwest Science and Technology University,Mianyang 621010,China)

机构地区：[1]中国市政工程西南设计研究总院有限公司,四川成都610031 [2]西南科技大学,四川绵阳621010

出　　处：《西南给排水》2023年第6期36-44,共9页Southwest Water & Wastewater

摘　　要：桩锚结构在基坑支护中应用广泛,但在设计计算时往往以经验为准,存在一定的盲目性和不确定性。依托在建工程,通过数值模拟分析了预留土作用下桩锚结构设计参数的变化对基坑力学性状的影响。结果表明:基坑围护桩的最大位移发生在桩顶,桩底的位移非常小;基坑周围地表沉降呈槽形分布,最大沉降位于距离基坑边缘5m左右的位置;弯矩分布曲线沿桩身有两个峰值点,峰值点大概位于距离桩底7m和13m处。当预应力锚索的锚固角为15°时支护桩的位移和弯矩、基坑周边地表的沉降都比较小;锚索锚固点距离桩顶越远,基坑支护桩位移、周边地表沉降量越大;当预应力大于200kN后,桩身位移和弯矩、地表沉降基本无变化。研究成果有助于揭示预留土和桩锚结构联合支护下基坑支护体系的工作机理,还可为同类基坑支护结构的优化设计提供参考和借鉴。Pile-anchor structure is widely used in foundation pit support,but the design and calcu-lation are always subject to experience,which has certain blindness and uncertainty.The influence of de-sign parameters of pile-anchor structure on mechanical properties of foundation pit under the action of reserved soil is analyzed by numerical simulation.The results show that the maximum displacement of foundation pit retaining pile occurs at the top of pile,while the displacement of pile bottom is very small.The surface settlement around the foundation pit is distributed in groove shape,and the maximum settle-ment is about 5m away from the edge of the foundation pit.The bending moment distribution curve has two peak points along the pile body,and the peak points are about 7m and 13m away from the pile bot-tom.When the anchoring Angle of prestressed anchor cable is 15°,the displacement and bending mo-ment of supporting pile and the surface settlement around the foundation pit are relatively small.The far-ther the anchorage point is from the pile top,the greater the displacement of foundation pit supporting pile and the surrounding surface settlement.When the prestress is greater than 200kN,the pile displace-ment,bending moment and ground settlement basically do not change.The research results are helpful to reveal the working mechanism of the foundation pit supporting system under the combined support of re-served soil and pile-anchor structure,and can also provide reference for the optimization design of simi-lar foundation pit supporting structure.

关 键 词：基坑 桩锚结构 预留土 力学性状 数值模拟 

分 类 号：TV551.4[水利工程—水利水电工程]