变截面桩竖向承载性状的模型实验研究  

Model test study of vertical bearing behaviors of variable cross-section piles

作　　者：罗照[1] 耿大新[1] 方焘[1,2] 

机构地区：[1]华东交通大学道桥与岩土工程研究所,江西南昌330013 [2]重庆大学土木工程学院,重庆400045

出　　处：《武汉大学学报（工学版）》2011年第6期731-734,756,共5页Engineering Journal of Wuhan University

基　　金：铁道部重点科技基金项目(编号:2009G010-D)

摘　　要：利用自行研发的试验装置进行了半桩模型试验研究,分析了变截面桩的荷载-沉降曲线、桩身轴力分布情况、桩身侧摩阻力分布情况,并与常规等截面桩进行比较.模型试验结果表明:变截面桩较等截面桩更有利于减小桩体的沉降量,但从单桩沉降变形的角度看,变截面桩存在最佳变径比.当变径比超过这一最佳值时,变径比越大,桩的沉降变形也就越大,甚至超过等截面桩的沉降量.桩顶荷载首先并主要通过变截面处以上桩身传递,该部分桩身段是主要承载部位.由于变截面处下部土体对桩的支撑作用,变截面桩的桩身轴力在变截面处附近有较大程度的衰减.变截面桩的桩身侧摩阻力比常规等截面桩发挥更加充分.This thesis carries on half pile model experiment research.A set of apparatus of foundation physical model are developed and utilized to conduct the model tests.We analyze the load-settlement curve,the distribution of axial force and lateral friction.The differences between constant cross-section pile and variable cross-section pile are compared.The results indicate that the variable cross-section pile is easier to reduce settlement than the constant cross-section pile.But from the viewpoint of the single pile settlement,there is an optimum ratio of variable diameter for the variable cross-section pile,when the ratio of variable diameter is beyond the optimum value,the settlement of pile increases as the ratio of variable diameter grows larger,or even more than the constnat cross-section pile.The vertical force on pile head is transferred through the part of pile which is above the position with variable cross-section.This part of pile resists most loads.For the soil under the position with variable cross section is serving as a support to the pile,the column load at the variable cross-section attenuates greatly.the lateral friction of variable cross-section pile is exerted more sufficiently than the constant cross-section pile.

关 键 词：变截面桩 模拟试验 竖向荷载 

分 类 号：TU473.1[建筑科学—结构工程]