边载作用下砂土桩基负摩阻力试验  

Experiment of Negative Skin Friction for Pile Foundation in Sand Under Two Side Load

作　　者：戴国亮[1,2] 黄挺[1,3] 龚维明[1,2] 缪云[1] 

机构地区：[1]东南大学土木工程学院,江苏南京210096 [2]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096 [3]河海大学港口海岸与近海工程学院,江苏南京210098

出　　处：《中国公路学报》2015年第1期1-7,共7页China Journal of Highway and Transport

基　　金：国家重点基础研究发展计划("九七三"计划)项目(2013CB036304);国家自然科学基金项目(51408185);"十二五"国家科技支撑计划项目(2011BAG07B01);江苏省自然科学基金项目(BK20130843);中国博士后科学基金项目(2014M561564)

摘　　要：为了研究两侧边载作用下群桩负摩阻力特性,进行了两侧边载作用下砂土中单桩和3×3群桩负摩阻力试验。作为对比,进行了围载作用下单桩和3×3群桩负摩阻力试验。研究了桩顶荷载与地面堆载共同作用下地基土沉降过程中桩基负摩阻力、中性点位置以及土体分层沉降的发展情况,分析了桩顶荷载和沉降关系、桩身轴力分布、桩身下拽力的影响规律。研究结果表明:两侧边载情况与围载情况相比较,桩顶沉降偏小,负摩阻力偏小,中性点位置偏高,群桩中不同位置桩所产生的负摩阻力分布规律与围载基本一致,但两侧边载作用下中间区域的桩与角桩负摩阻力的差值更明显;与围载情况相反的是两侧边载作用下群桩内、外土层沉降比随土表荷载的增加而减少。In order tO investigate the characteristics of the negative skin friction（NSF） for pile group under two side load, model tests were conducted for the single pile and pile group with 3 X 3 piles under two side load as well as under surrounding load for comparison. The NSF, the position of the neutral point and the interior layer settlement development in soil were studied under the combined action of the load at the pile head and the load at soil surface. The results were also presented on the relationship between the load at pile head and the settlement, the distribution of the axial force and the influence law of the drag force of the pile body. The results show that the pile head settlement and negative skin friction under two side load are smaller than that under the surrounding load, but the location of neutral point is higher. The distribution characteristics of NSF by the pile at different position in pile group under two side load are almost the same as that under surrounding load, but the difference of NSF between the middle pile and the corner pile is more obvious. Contrary to the surrounding load, for two side load the settlement ratio of interior soil to exterior soil decreases with the increase of the load at soil surface.

关 键 词：道路工程 桩基础 模型试验 负摩阻力 群桩效应 边载 

分 类 号：U416.1[交通运输工程—道路与铁道工程]