基于球孔扩张理论的静压桩承载力时效性研究  

Time effect of bearing capacity of jacked piles based on spherical cavity expansion theory

作　　者：王家涛[1] 张明义[2] 

机构地区：[1]山东水利职业学院建筑工程系,山东日照276826 [2]青岛理工大学土木工程学院,山东青岛266033

出　　处：《四川建筑科学研究》2011年第2期120-124,共5页Sichuan Building Science

基　　金：国家自然科学基金项目(50678086);山东省高等学校优秀青年教师国内访问学者项目

摘　　要：通过研究软土地基中静压桩的承载性状发现,静压桩的单桩承载力随时间的提高主要来源于桩侧摩阻力的增长,而桩端阻力变化对承载力的时间效应影响较小。静压桩承载力随时间增长的关系,可以用对数曲线描述。根据静压桩的贯入机制,将沉桩过程模拟为半无限土体中一系列球孔的连续扩张,土体假定为Mohr-Coulomb材料。基于球孔扩张理论,计算出不同时期桩侧极限摩阻力和桩端阻力,从而进一步求得不同休止期的静压桩极限承载力。与现场试验资料对比分析表明,计算值与实测值的变化规律一致,且误差较小,能够满足工程需要。Through the study on the characteristics of bearing capacity of jacked pile in soft soil,it is found that the increasing of ultimate bearing capacity of the single pile is mainly determined by pile side resistance.The end resistance has little influence on the time effect of bearing capacity of pile.The relationship between ultimate bearing capacity and time can be described with logarithmic curve.According to penetration mechanism of jacked pile,the expansion of a series of spherical cavities in semi-infinite space is used to simulate the process of pile installation;and soil is assumed as Mohr-Coulomb material.Based on the theory of spherical cavity expansion,an estimating formula was proposed to calculate the ultimate side frictional resistance and end resistance.Then the ultimate bearing capacity of single pile in different time can be obtained.Analyses show that the calculation results are close to the measured data and the error between computed and measured value is little,so the prediction model can be applied to the practical engineering.

关 键 词：静压桩 侧阻力 端阻力 时效性 极限承载力 

分 类 号：TU473[建筑科学—结构工程]