基坑开挖对邻近桩基竖向受荷性状的影响  

Axial Response of a Compression Pile to Nearby Excavation

作　　者：万嘉成 李卫超[1] 曾英俊 上官士青 WAN Jiacheng;LI Weichao;ZENG Yingjun;SHANGGUAN Shiqing(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092;Shanghai Urban Construction Municipal Engineering（Group）Co.,Ltd.,Shanghai 200065;CCCC highway consultants Co,Ltd.,Shanghai Branch,Shanghai 200082)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]上海城建市政工程(集团)有限公司,上海200065 [3]中交公路规划设计院有限公司上海分公司,上海200082

出　　处：《现代隧道技术》2018年第5期124-132,共9页Modern Tunnelling Technology

摘　　要：软土地区基坑开挖时一个重要的环境问题是土体移动对邻近桩基的影响。文章通过建立三维有限元模型,对软土地区中基坑开挖对邻近桩基竖向受荷性状影响进行研究。研究结果表明,基坑开挖前后桩基轴向抗压承载力减小约13.6%,并且引起既有承受竖向荷载的邻近桩基产生可观的附加沉降。为此,针对桩土接触力随基坑开挖的变化规律进行了系统的分析,并基于分析结果,通过考虑开挖后桩侧极限摩阻力的降低,对单桩沉降计算的荷载传递法进行改进,使得能考虑开挖对邻近桩基竖向受荷性状的影响。One of the major concern in the excavation in soft soil areas is the effect of soil movement on adjacent pile foundations. In this paper, three-dimensional finite element models are established to study the axial response of the adjacent pile foundations close to an excavation in soft soil. The results show that, due to the nearby excavation, the axial bearing capacity of a single pile under compression decreases about 13.6%, and considerable additional settlements of a single pile subjected to the working compression load are generated. Therefore, the characteristics of load transfer mechanism between pile shaft and around soil, as well as the tip soil reaction are investigated extensively, which demonstrates that, as expected, the nearby excavation leads to a reduction of ultimate soil friction resistance. Furtherly, the widely employed load transfer method for pile foundation is modified to consider the effects of nearby excavation, which can be employed to predict the axial response of an axially loaded pile foundation beside an excavation.

关 键 词：基坑开挖 桩基 轴向响应 荷载传递法 

分 类 号：TV551.42[水利工程—水利水电工程]