软土基坑中斜桩内撑支护效果实测与数值分析  

Field Measurement and Numerical Analysis of Inclined Pile Internal Support in Soft Soil Foundation Pit

作　　者：陈雷 陈峰 黎小龙 CHEN Lei;CHEN Feng;LI Xiaolong(Ningbo Jiangong Engineering Group Co.,Ltd.,Ningbo 315000,Zhejiang,China)

机构地区：[1]宁波建工工程集团有限公司,浙江宁波315000

出　　处：《建筑施工》2024年第12期1941-1945,共5页Building Construction

基　　金：宁波建工工程集团有限公司研发项目(JGGC-YF-24017)。

摘　　要：以宁波市某地块基坑深开挖工程为例,利用有限元软件,对比了斜桩内撑、双排桩与单排桩支护体系的围护效果,并结合现场实测数据,探讨了斜桩内撑支护体系的作用机理。结果表明:斜桩内撑支护体系在工程中取得了良好的应用效果,尤其是控制桩顶水平位移具有优异的性能,直桩的桩顶最大水平位移小于10 mm,其围护效果优于单排桩,略逊于双排桩;斜桩内撑的直桩桩身正弯矩最大点出现在1倍开挖深度附近,斜撑桩桩身轴力最大点出现在桩顶,加强垫层的存在有助于提高桩身受力特性;斜桩内撑的作用机理在于直桩、斜撑桩与冠梁三者刚接形成类三角形空间刚架,增大了支护体系的整体刚度,斜撑桩通过轴力补偿,发挥了类似水平支撑的作用,抵消部分主动土压力,进而增大了其对于桩身位移、坑外土体沉降的控制。研究方法为在软土地区使用斜桩内撑支护体系提供了范例,部分结论可为相似的基坑工程设计、施工提供参考。Using a deep foundation pit excavation project in Ningbo as an example,the supporting effects of inclined pile internal support,double-row pile,and single-row pile systems are compared with finite element software,and the mechanism of the inclined pile internal support system is discussed based on field measurements.Results indicate that the inclined pile internal support system performs well,especially in controlling horizontal displacement at the pile top.The maximum horizontal displacement of the vertical pile top is less than 10 mm,with better performance than the single-row pile and slightly lower than the double-row pile.The maximum positive bending moment in the vertical pile appears near the excavation depth,and the maximum axial force in the inclined pile is at the pile top.The presence of a reinforced cushion improves the mechanical characteristics of the pile.The inclined pile internal support mechanism involves rigid connections among the vertical pile,inclined pile,and crown beam,forming a triangle-like spatial rigid frame that enhances overall system stiffness.The inclined piles,by compensating for axial forces,act similarly to horizontal supports,counteracting part of the active earth pressure and thereby enhancing control over pile displacement and soil settlement outside the pit.This approach provides a reference for inclined pile internal support systems in soft soil areas and offers insights for the design and construction of similar foundation pit projects.

关 键 词：斜桩内撑 数值模拟 桩身位移 土体沉降 

分 类 号：TU753[建筑科学—建筑技术科学]