基于改进虚土桩法的扩底桩沉降计算方法  

Settlement calculation method of belled pile based on modified virtual-soil pile method

作　　者：乔世范[1] 董常瑞 王刚[1] 蔡子勇 谭晶仁 刘钰 Qiao Shifan;Dong Changrui;Wang Gang;Cai Ziyong;Tan Jingren;Liu Yu(Central South University,Changsha 410075,China)

机构地区：[1]中南大学,湖南长沙410075

出　　处：《土木工程学报》2022年第7期98-107,共10页China Civil Engineering Journal

基　　金：中国铁路总公司科技研究开发计划重点课题(2017G007-D,2017G008-J);中国中铁股份有限公司科技研究开发计划重点课题(20192001)。

摘　　要：基于佐藤·悟的荷载传递模型,考虑桩身自重及桩侧土深度效应对虚土桩法进行改进,并以扩散角的形式来考虑桩端的应力扩散效应,推导层状地基中扩底桩的沉降计算方法;提出改进的虚土桩计算流程,无需针对虚土桩长进行试算,减少计算成本;将改进虚土桩法计算得到的荷载-沉降曲线与实测数据及现有扩底桩沉降计算方法进行对比,并分析桩身直径、扩大段直径以及桩长等因素对扩底桩沉降和承载力的影响规律。结果表明:在考虑土体自重、深度效应等因素作用下计算所得到的桩顶荷载-沉降曲线与实测曲线吻合更好,能更加准确反映扩底桩的沉降规律。Based on Sato Wu’s load transfer model,the virtual-soil pile method is modified by considering the self-weight of the pile and the depth effect of soil beside the pile.The stress diffusion effect at the end of the pile is considered in the form of diffusion angle,and the settlement calculation formula of the belled pile in the layered foundation are derived.The calculation process of the virtual-soil pile is modified,in which the trial calculation for the length of the virtual-soil pile is cancelled,so the calculation efficiency is greatly improved.The load-settlement curve calculated by the modified virtual-soil pile method is compared with the measured data and settlement by the existing calculation method of belled pile.The effect of pile diameter,enlarged section diameter,and pile length on the settlement and the bearing capacity is analyzed.The load-settlement curve of the pile top calculated by the modified method is in good agreement with the measured curve,which indicates that the settlement trend of the belled pile can be well reflected by the proposed method.

关 键 词：扩底桩沉降特性 改进虚土桩模型 标定虚土桩长 因素分析 

分 类 号：TU473.11[建筑科学—结构工程]