素混凝土桩复合地基支承路堤变形破坏模式  

Deformation and failure modes of embankments on soft ground reinforced by plain concrete piles

作　　者：黄俊杰[1,2] 王薇 苏谦[1,2] 李婷[1] 王迅[1] HUANG Jun-jie;WANG Weit;SU Qian;LI Ting;WANG Xun(School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China;Key Laboratory of High-Speed Railway Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu, Sicbuan 610031, China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《岩土力学》2018年第5期1653-1661,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51508478)~~

摘　　要：为了分析素混凝土桩复合地基支承路堤沉降变形特征和失稳破坏机制,建立了3组不同桩间距的素混凝土桩复合地基支承路堤离心试验模型及其数值模型。结果表明:在路堤填土自重、轨道和车辆荷载作用下,改变桩间距对素混凝土桩复合地基支承路堤沉降变形、桩体应变、加筋垫层和桩体破坏模式具有显著的影响;当桩间距不大于4倍桩径时,加筋垫层整体基本保持完好,路堤下素混凝土桩复合地基沉降能逐渐趋于稳定,而桩间距达到6倍桩径后,桩顶刺穿加筋垫层,加筋垫层对桩土变形协调和传递荷载作用失效,素混凝土桩复合地基支承路堤沉降持续增大;当桩间距达到4倍桩径时,素混凝土桩最大应变值发生随上部荷载的增大反而减小的突变现象,最靠近坡脚的素混凝土桩最先产生弯曲破坏而不是剪切破坏,当桩间距增大至6倍桩径时,桩体弯曲破坏逐渐往路堤中心方向发展。To analyze the settlement and deformation characteristics and the failure modes of embankments on soft ground reinforced by plain concrete piles, three centrifugal test models of the embankments on soft ground reinforced by plain concrete piles with different spaces between piles and their numerical models have been performed. The results show that changing pile spacing has a remarkable effect on the settlement and deformation, the pile shaft strain, the failure modes of piles and reinforced cushion of the models, under embankment self-weight load, and track structure and vehicle load. When the pile spacing is not greater than 4 times of the pile diameter, the reinforced cushion can basically maintain integrity, the settlement of the models gradually tends to stabilize. Once the pile spacing increases to 6 times of the pile diameter, the reinforced cushion is impaled, the function of deformation coordination and load transfer would not be available, resulting in a continual increase of the settlement of the model embankments. While the pile spacing reaches 4 times of the pile diameter, an abrupt decrease in the maximal strain value of the piles occurs with increasing upper load, and the plain concrete piles near the embankment toe fail firstly in bending failure mode rather than shear failure mode. The plain concrete piles closer to the embankment center fail gradually in bending failure mode as the pile spacing increases to 6 times of the pile diameter.

关 键 词：复合地基 素混凝土桩 加筋垫层 变形破坏模式 

分 类 号：TU473[建筑科学—结构工程]