软土桩基上拓宽路堤的变形破坏离心模型试验  

Centrifugal Modeling Test on Deformation and Failure Behavior of Widening Embankment on Soft Soil with Pile Foundation

作　　者：陈达章 陈天翼 牟太平 张嘎[2] CHEN Da-zhang;CHEN Tian-yi;MOU Tai-ping;ZHANG Ga(Guangdong Provincial Freeway Co.,Ltd.,Guangzhou 510623,Guangdong,China;School of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]广东省高速公路有限公司,广东广州510623 [2]清华大学土木水利学院,北京100084

出　　处：《建筑科学与工程学报》2021年第6期11-17,共7页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金重点项目(52039005)。

摘　　要：采用离心模型试验手段,以广州高速公路改扩建工程为背景建立模型,设计相应尺寸的模型试验方案,模拟软土桩基上的新路堤拓宽过程,研究软土桩基的变形破坏规律与机理。结果表明:旧路堤主要发生竖向位移,新路堤发生沉降和一定量水平位移;新路堤坡肩区域出现向坡脚滑动趋势,导致新路堤施工过程中路堤和软基产生滑动破坏;新路堤中的滑裂面首先出现,从新路堤坡肩到短桩顶端自上而下逐渐形成;在新路堤滑裂面形成过程中,软基中的滑裂面从旧路堤下的地基表面至新路堤坡脚下地基部分自内向外逐渐形成,2条滑裂面几乎同时达到贯通状态;管桩发生一定程度的倾斜,在滑裂面出现之前的某一时刻倾斜角度迅速增加;在局部滑裂面附近位移出现较快增长,变形较为集中;变形局部化导致了局部发生破坏,而局部破坏促进了变形局部化的进一步发展,二者的耦合发展最终导致土体发生破坏。The centrifugal modeling test method was used to establish the model based on the reconstruction and expansion project of Guangzhou expressway,and the modeling test scheme of corresponding size was designed to simulate the widening process of new embankment on soft soil pile foundation.The deformation and failure law and mechanism of soft soil pile foundation were studied.The results show that the old embankment mainly has vertical displacement,while the new embankment has settlement and a certain amount of horizontal displacement.The slope shoulder area of the new embankment tends to slide towards the slope toe,which leads to sliding failure in the embankment and soft foundation during the construction of the new embankment.The slip surface in the new embankment appears first,and gradually forms from top to bottom from the slope shoulder of the new embankment to the top of the short pile.During the formation of the sliding surface of the new embankment,the sliding surface in the soft foundation is gradually formed from the foundation surface under the old embankment to the foundation at the foot of the new embankment slope.The two slip surfaces almost reach the through state at the same time.The pipe pile tilts to a certain extent,and the inclination angle increases rapidly at a certain time before the slip surface appears.Near the local slip surface,the displacement increases rapidly and the deformation is concentrated.Deformation localization leads to local failure,and local failure promotes the further development of deformation localization.The coupling development of the two eventually leads to the failure of soil.

关 键 词：软土 路堤拓宽 桩基 变形 破坏 离心模型试验 

分 类 号：TU433[建筑科学—岩土工程]