工程科学学报，第40卷，第3期：285-292,2018年3月 Chinese Journal of Engineering,Vol.40,No.3:285-292,March 2018 DOI:10.13374/j.issn2095-9389.2018.03.004:http://journals.ustb.edu.cn 黏土中静压沉桩离心模型 李雨浓)，Barry M Lehane),刘清秉) 1)燕山大学建筑工程与力学学院，秦皇岛0660042)西澳大学土木工程与资源学院，珀斯60093)中国地质大学（武汉）三峡研究中心， 武汉430074 ☒通信作者，E-mail:liyunong-ren@163.com 摘要采用西澳大学室内鼓轮式离心机，在预先固结的高岭黏土中开展不同离心力场(50g,125g及250g,g为重力加速度) 条件下的模型压桩试验、Tb试验和静力触探试验，分析了模型桩在贯入过程、静置稳定过程中桩身径向应力（σ，）的变化规 律，并对后期桩体拉伸载荷阶段的径向应力变化值（△σ）及桩侧摩阻力变化情况行了探讨，揭示了在不同超固结比(OCRs)黏 土中静压桩侧摩阻力的演变特性.在此基础上，通过两种经验公式方法对桩侧摩承载力进行了预测计算和对比分析.研究结 果表明：沉桩过程中桩端相对高度(h/B)对桩身径向应力的发展变化有很大的影响，桩身不同位置(/B)的总径向应力对同 一贯入深度而言，存在桩侧径向应力退化现象：基于静力触探试验提出的经验方法，能有效考虑静力触探锥端阻力(q,)和桩端 相对高度(h/B)因素的影响，将其应用于黏土沉桩时桩侧摩阻力的预测，可取得与试验实测结果较吻合的结果.研究成果对 软土地区静压桩施工与承载力设计具有一定的工程指导意义. 关键词静压桩：径向应力：黏土：桩侧承载力：离心模型 分类号TU473.1 Centrifuge modeling of jacked pile in clay LI Yu-nong9,Barry M Lehane》,LIU Qing-bing》 1)College of Civil Engineering Mechanics,Yanshan University,Qinhuangdao 066004,China 2)School of Civil and Resource Engineering,University of Western Australia,Perth 6009,Australia 3)Three Gorges Research Center,China University of Geosciences,Wuhan 430074,China Corresponding author,E-mail:liyunong-ren@163.com ABSTRACT Notable contributions to our improved understanding of jacked pile behavior in sand have been achieved through instru- mented model pile tests in laboratory test chambers,at elevated g-evels in the centrifuge,and in the field.In recent years,research focusing on pile behavior in clay has declined.Consequently,predictive methods for pile capacity have not advanced beyond those pro- vided in American Petroleum Institute (API 2000)recommendations,which were based on research conducted in the early 1980s.This paper re-focuses attention on the shaft capacity of jacked piles in clay.Three centrifuge scale pile tests were performed in kaolin clay in the drum centrifuge at the University of Western Australia.The tests were performed in pre-consolidated blocks of kaolin,and were subsequently spun in the centrifuge at three different g-evels of 50g,125g and 250g respectively.The piles were equipped with total pressure sensors located at different depths and were installed by jacking into samples of reconstituted kaolin clay.The kaolin clay sam- ples were prepared to measure the range of the cone penetration test end resistance ()undrained strengths (s),and overconsol- idation ratios (OCRs).These pile tests were used to investigate the lateral stress changes (developed along the pile shafts during pile installation and equalization.In addition,the change in the value of lateral stress (Ao,)and the changes in pile shaft resistance during the pile tension test were discussed.The characteristics of the jacked pile in the clay with different over-consolidation ratios (OCRs)were revealed.Furthermore,the centrifuge data were subsequently used to examine the current design methods for the evalua- tion of the shaft capacity of displacement piles in clay.The centrifuge test results show that during the pile penetration,a strong de- 收稿日期：201704-11 基金项目：国家自然科学基金青年基金资助项目(51408527)：河北省自然科学基金青年基金资助项目(E2015203195)工程科学学报，第 40 卷，第 3 期: 285--292，2018 年 3 月 Chinese Journal of Engineering，Vol． 40，No． 3: 285--292，March 2018 DOI: 10． 13374 /j． issn2095--9389． 2018． 03． 004; http: / /journals． ustb． edu． cn 黏土中静压沉桩离心模型 李雨浓1) ，Barry M Lehane2) ，刘清秉3) 1) 燕山大学建筑工程与力学学院，秦皇岛 066004 2) 西澳大学土木工程与资源学院，珀斯 6009 3) 中国地质大学( 武汉) 三峡研究中心， 武汉 430074  通信作者，E-mail: liyunong-ren@ 163． com 摘 要 采用西澳大学室内鼓轮式离心机，在预先固结的高岭黏土中开展不同离心力场( 50g，125g 及 250g，g 为重力加速度) 条件下的模型压桩试验、T--bar 试验和静力触探试验，分析了模型桩在贯入过程、静置稳定过程中桩身径向应力( σr ) 的变化规 律，并对后期桩体拉伸载荷阶段的径向应力变化值( Δσr ) 及桩侧摩阻力变化情况行了探讨，揭示了在不同超固结比( OCＲs) 黏 土中静压桩侧摩阻力的演变特性． 在此基础上，通过两种经验公式方法对桩侧摩承载力进行了预测计算和对比分析． 研究结 果表明: 沉桩过程中桩端相对高度( h/B) 对桩身径向应力的发展变化有很大的影响，桩身不同位置( h/B) 的总径向应力对同 一贯入深度而言，存在桩侧径向应力退化现象; 基于静力触探试验提出的经验方法，能有效考虑静力触探锥端阻力( qt ) 和桩端 相对高度( h/B) 因素的影响，将其应用于黏土沉桩时桩侧摩阻力的预测，可取得与试验实测结果较吻合的结果． 研究成果对 软土地区静压桩施工与承载力设计具有一定的工程指导意义． 关键词 静压桩; 径向应力; 黏土; 桩侧承载力; 离心模型 分类号 TU473. 1 收稿日期: 2017--04--11 基金项目: 国家自然科学基金青年基金资助项目( 51408527) ; 河北省自然科学基金青年基金资助项目( E2015203195) Centrifuge modeling of jacked pile in clay LI Yu-nong1)  ，Barry M Lehane2) ，LIU Qing-bing3) 1) College of Civil Engineering ＆ Mechanics，Yanshan University，Qinhuangdao 066004，China 2) School of Civil and Ｒesource Engineering，University of Western Australia，Perth 6009，Australia 3) Three Gorges Ｒesearch Center，China University of Geosciences，Wuhan 430074，China  Corresponding author，E-mail: liyunong-ren@ 163． com ABSTＲACT Notable contributions to our improved understanding of jacked pile behavior in sand have been achieved through instru￾mented model pile tests in laboratory test chambers，at elevated g-levels in the centrifuge，and in the field． In recent years，research focusing on pile behavior in clay has declined． Consequently，predictive methods for pile capacity have not advanced beyond those pro￾vided in American Petroleum Institute ( API 2000) recommendations，which were based on research conducted in the early 1980s． This paper re-focuses attention on the shaft capacity of jacked piles in clay． Three centrifuge scale pile tests were performed in kaolin clay in the drum centrifuge at the University of Western Australia． The tests were performed in pre-consolidated blocks of kaolin，and were subsequently spun in the centrifuge at three different g-levels of 50g，125g and 250g respectively． The piles were equipped with total pressure sensors located at different depths and were installed by jacking into samples of reconstituted kaolin clay． The kaolin clay sam￾ples were prepared to measure the range of the cone penetration test end resistance ( qt ) ，undrained strengths ( su-Tbar ) ，and overconsol￾idation ratios ( OCＲs) ． These pile tests were used to investigate the lateral stress changes ( σr ) developed along the pile shafts during pile installation and equalization． In addition，the change in the value of lateral stress ( Δσr ) and the changes in pile shaft resistance during the pile tension test were discussed． The characteristics of the jacked pile in the clay with different over-consolidation ratios ( OCＲs) were revealed． Furthermore，the centrifuge data were subsequently used to examine the current design methods for the evalua￾tion of the shaft capacity of displacement piles in clay． The centrifuge test results show that during the pile penetration，a strong de-