静压沉桩与CPTU贯入离心模型试验及机制研究  

Centrifugal model test and mechanism study of jacked pile and CPTU penetration

作　　者：李镜培[1,2] 操小兵 李林[1,2] 龚卫兵[1,2] LI Jing-pei;CAO Xiao-bing;LI Lin;GONG Wei-bing(Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092

出　　处：《岩土力学》2018年第12期4305-4312,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41272288)~~

摘　　要：为了探究静压沉桩与CPTU贯入力学机制,开展了饱和黏土中静压沉桩及CPTU贯入的离心模型试验,获得了静压沉桩与CPTU贯入过程中土压力、超孔压和贯入阻力的变化规律。同时,将静压桩和CPTU压入过程视为一系列球孔的连续贯入,应用圆孔扩张解答,建立了静压沉桩和CPTU贯入过程中锥头阻力、侧阻力与超孔压的预测方法。通过离心模型试验和理论预测结果的对比分析表明:随着桩体的压入,桩周土体的超孔压和土压力均逐渐增大,当桩头通过监测点时,超孔压与土压力均达到最大值;在饱和黏土中,CPTU锥头阻力、锥侧摩阻力和锥头超孔压与锥头贯入深度总体上呈线性关系。预测方法估算沉桩和CPTU贯入引起的土压力、超孔压与模型试验结果相符,较好地反映了饱和黏土中静压沉桩和CPTU贯入的力学机制。To explore the mechanisms of jacked pile and CPTU penetration, centrifugal model tests are conducted to investigate the variations of earth pressure, excess pore pressure and penetration resistance in the process of jacked pile and CPTU penetration. Meanwhile the installation process of jacked pile and CPTU is regarded as a series of continuous sphere cavity penetration. The cone resistance, the cone side resistance and the excess pore pressure are predicted based on spherical cavity expansion theory. The comparisons between centrifugal model test data and theoretical predictions show that the excess pore pressure and the soil stress around the pile increase with the increase of penetration depth. The excess pore pressure and the soil pressure reach the maximum when the pile tip arrives the measured point. The cone resistance, the cone side friction and the excess pore pressure show linear relationship with the cone penetration depth in saturated clays. The calculated results show a good agreement with the test results, which presents the mechanisms of jacked pile and CPTU penetration well.

关 键 词：静压桩 CPTU贯入 离心模型试验 沉桩 

分 类 号：TU473[建筑科学—结构工程]