沉降对应的支盘桩承载力控制方法研究  

A controlling method of the settlement-induced bearing capacity of squeezed branch piles

作　　者：潘玲 熊力 何志军 李国维[2] 周洋[3] PAN Ling;XIONG Li;HE Zhijun;LI Guowei;ZHOU Yang(Guangdong Hualu Transportation Technology Co.,Ltd.,Guangzhou,Guangdong 510420,China;Key Laboratory ofMinistry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China;Henan University of Technology,Zhengzhou,Henan 450001,China)

机构地区：[1]广东华路交通科技有限公司,广东广州510420 [2]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [3]河南工业大学,河南郑州450001

出　　处：《岩石力学与工程学报》2024年第10期2443-2454,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(42177126)。

摘　　要：支盘桩在小沉降变形增量下可产生显著的承载力增量,控制桩顶荷载和沉降同时达到控制标准能够充分发挥支盘桩承载潜力。首先基于理论分析,引入0.5倍极限承载力对应的位移参数建立无临界位移的支盘桩荷载传递方程;基于Meyerhof地基承载力理论建立盘周土体破坏模型并确定直杆段侧阻力的有效作用长度;建立不同盘间距下支盘桩桩土破坏模型,基于桩土破坏模型和临界桩顶位移对应的盘承载力确定最优盘间距;基于桩顶设计边界条件和桩端控制边界条件改进荷载传递分析方法,建立沉降对应的支盘桩承载力控制方法,一次性实现承载力和沉降双控目标。其次,开展现场试桩静载试验结合数值模拟验证支盘桩桩土破坏模型并确定荷载传递方程计算参数。最后,通过上述理论优化现场工况下支盘桩桩长及支盘桩布置,验算案例在满足设计要求的条件下较原方案桩长减少缩短14.3 m,减少3支1盘,并且极限承载力理论值与数值模型计算值误差为2.9%。The load-bearing capacity of squeezed branch piles(SBPs) can significantly increase under small incremental settlement deformations.By simultaneously controlling the pile top load and settlement to meet control requirements,the full potential of the SBP's bearing capacity can be realized.This study introduced a load transfer equation for SBPs without critical displacement,incorporating the displacement parameter corresponding to 0.5times the ultimate bearing capacity.A failure model for the soil around the bulb was established based on Meyerhof's bearing capacity theory,determining the effective length of the shaft resistance in the straight section.A pile-soil failure model for SBPs with different bulb spacing was developed,identifying the optimal bulb spacing.An improved load transfer analysis method,considering both pile top design boundary conditions and pile tip control boundary conditions,enables synergistic control of both bearing capacity and settlement,achieving dual control targets.Field static load tests combined with numerical simulations verified the pile-soil failure model of SBPs and determined parameters for the load transfer equation.The theoretical framework optimized the pile length and layout of bulbs or branches under field conditions.Case verification showed that,while meeting design requirements,the optimized scheme reduces pile length by 14.3 meters,with a reduction of 3 branches and 1 bulb.The error between the theoretical ultimate bearing capacity and the numerical model calculation is 2.9%.

关 键 词：桩基础 支盘桩 改进荷载传递法 原位试验 极限承载力计算 沉降控制 

分 类 号：TU473[建筑科学—结构工程]