湿陷性黄土桩网复合地基沉降控制离心模型试验  

Analysis on Settlement Controlling Effect of pile-net Composite Foundation on Collapsible Loess by Centrifugal Model Tests

作　　者：王长丹[1] 王炳龙[1] 王旭[2] 周顺华[1] 

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《铁道学报》2011年第4期84-92,共9页Journal of the China Railway Society

基　　金：国家863计划(2007AA11Z116);铁道部科技研究开发计划项目(2007G046)

摘　　要：为研究和分析高速铁路荷载作用下刚性桩桩网复合地基控制湿陷性黄土地基沉降的效应,采用离心模型试验的方法对不同桩间距设置条件下的刚性桩桩网复合地基进行了模拟试验。试验研究表明:湿陷性黄土地基无法满足高速铁路有砟轨道对路基工后沉降的要求,需要加固处理;随着桩间距由2倍桩径增至6倍桩径,地基工后沉降量增大,差异沉降量增大,桩土荷载应力分担比增大,桩间土对桩体的负摩阻力增大;桩帽的设置可以有效地控制地基工后沉降量和沉降速率,减小差异沉降;桩间土与桩体相对位移中性点位置随着桩间距的增大而显著降低;桩体刺入垫层量值会随桩间距增大在施工阶段显著增加,而在工后阶段呈减少趋势。On the basis of already-conducted experimental study at home and abroad,the centrifugal model test is used to imitate the pile-net composite foundaton with different pile spacing so as to study the settlement controlling ability of the pile-net composite foundation on collapsible loess ground.The research results show as follows：The collapsible loess ground cannot meet the requirements of settlement after construction of ballasted tracks of high-speed railways and it needs to be reinforced;the settlement after construction,differential settlement,pile-soil load share ratio and negative skin friction of the pile get larger with extending of pile spacing by two to six times of the pile diameter;Settlement settlement rate after construction can be controlled effectively and differential settlement can be reduced by setting of the pile-cap;the neutral point of the relative displacement between the pile and inter-pile soil drops obviously with extending of pile spacing;the value of the relative displacement between the pile and cushion increases with extending of pile spacing in the construction stage and decreases after construction.

关 键 词：路基工程 湿陷性黄土 刚性桩 桩网复合地基 离心模型试验 沉降 

分 类 号：TU411.93[建筑科学—岩土工程] U213.15[建筑科学—土工工程]