摘要
采用耦合欧拉-拉格朗日(CEL)有限元法分别建立单桩模型、预钻孔单桩模型、压入桩和隔离桩并存的双桩模型,研究桩周土体位移场变化规律,探讨预钻孔、隔离桩对挤土效应的控制效果。结果表明:管桩静压过程中,压桩深度不同,土体径向水平位移沿深度分布规律也不同,但其最大值始终出现在桩尖附近,且距桩尖下6~7 d(d为桩径)深度以下土体不受压桩影响;当桩压入深度大于8 d后,土体由浅层破坏转至深层破坏,对地表隆起的影响不再明显;压桩完成后,土体径向位移随与桩距离的增大呈指数型衰减。预钻孔深度越大,对挤土效应控制效果越好;隔离桩可以大大削弱其背侧土体的挤土变形量,且使发生最大径向水平位移的位置由桩尖附近向上转移至0.5L(L为桩长)深度处。CEL有限元法适用于静压管桩挤土效应分析,可推广应用于诸如沉桩、桩靴贯入等考虑大变形岩土工程问题的研究。
This paper used the coupled euler-lagrangian(CEL)method to establish three models,including a single-pile model,a single-pile model with pre-drilled hole,and a double-piles model with an isolated pile,aiming to study the soil displacement distribution around the pile and to investigate the control effect of pre-drilled hole and isolated pile on soil squeezing deformation.Results show that during the penetration process of pipe pile,the horizontal displacement distribution of soil along the depth varies with the penetration depth of pile,and the maximum displacement occurs near the depth of the pile tip.Furthermore,the soil under the depth of 6~7 d(d is the pile diameter)below pile tip is not affected by the pile penetration.When the pile penetration depth is larger than 8 d,the uplift deformation of ground surface caused by the yield failure of the deep soil gradually disappear.After the pile is fully penetrated,the horizontal displacement decreases exponentially as the distance from the pile increases.In addition,as the depth of pre-drilled hole increases,the control effect of pre-drilled hole on soil squeezing deformation becomes more effective.The isolated pile can significantly reduce the horizontal displacement of soil on the back side of the isolated pile,and can transfer the position of soil depth where occures maximum horizontal displacement from near the pile tip to a depth of 0.5 L(L is the pile length).The CEL approach is well suited to study the influences of pile penetration on the surrounding soil,and can be widely applied to the researches of geotechnical problems involving the large deformations,such as pile installation and spudcan penetration.
作者
魏丽敏
李双龙
杜猛
张红
何群
WEI Limin;LI Shuanglong;DU Meng;ZHANG Hong;HE Qun(School of Civil Engineering, Central South University, Changsha 410075, Hunan,China;China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, Sichuan,China;Railway No.10 Engineering Group Co., Ltd.,Ji'nan 250001, Shandong, China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第4期28-38,共11页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51878671)
中国铁路总公司科技研究开发计划项目(2017G008-I)。
关键词
耦合欧拉-拉格朗日法
挤土效应
数值分析
预钻孔
隔离桩
coupled eulerian-lagrangian method
soil squeezing effect
numerical analysis
pre-drilled hole
isolated pile
