摘要
为研究自重湿陷性黄土场地中钻孔灌注桩的竖向承载性状,开展了3根试桩在天然、先加载后浸水和预浸水3种工况下的静载荷试验.试验结果表明,桩顶沉降随桩顶荷载的增加而增大,桩侧摩阻力随桩土相对位移的增加而增大,某些深度处桩侧摩阻力在达到峰值后甚至减小.桩顶荷载传至桩底后桩端反力随桩顶荷载的增加而增大,其变化速率逐渐增大.在本试验小试坑浸水及场地地层条件下,桩顶未施加荷载时桩侧未产生负摩阻力;桩顶维持4000 kN荷载不变时桩周土体浸水湿陷,桩侧正摩阻力减小,桩顶沉降增大,但也未在桩侧产生负摩阻力.桩周土体浸水软化,其所能提供的最大侧摩阻力减小.
Field tests were conducted to investigate vertical bearing behaviors of the cast-in-place pile in collapsible loess site under natural,post-soaked and pre-soaked conditions.Test results show that the settlement at pile top increases when the vertical load applied at pile top increases.The skin friction increase with the increase of the relative displacement between pile and soil,while at some depths,they even decrease after reaching their peaks.The pile tip resistance increases with the increase of the vertical load after the applied load was transferred to pile tip,and the changing rate increases gradually.On conditions of the relatively small soaking pit and the stratum of the test site,there is no occurrence of the negative skin friction during soaking with no vertical load applied at pile top.When maintaining a 4000 kN load at pile top,after soaking the loess around pile collapses,the positive skin friction decreases,and the settlement at pile top increases,while the negative skin friction does not occur.The loess was softened after soaking,leading to the decrease of the maximum skin friction provided by it.
作者
张磊
罗少锋
鲁洁
ZHANG Lei;LUO Shaofeng;LU Jie(School of Civil Engineering,Xi′an Univ.of Arch.&Tech.,Xi′an 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi′an Univ of Arch&Tech.,Xi′an 710055,China)
出处
《西安建筑科技大学学报（自然科学版）》
北大核心
2019年第4期532-537,共6页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
国家自然科学基金项目(51508455)
陕西省自然科学基础研究计划项目(2019JM-232)
西安建筑科技大学青年科技基金项目(QN1614)
关键词
桩基础
湿陷性黄土
浸水试验
竖向荷载
侧摩阻力
pile foundations
collapsible loess
immersion test
vertical loads
skin friction
