加固范围及边坡坡率对CFG桩–网复合地基受力变形特性影响分析  

Effect of the strengthening area and the slope rate on bearing and deforming behaviors of CFG pile-geogrid composite foundations

作　　者：张树明[1,2] 蒋关鲁[1,2] 廖祎来 杜登峰 黄昊威 刘勇[3] ZHANG Shuming;JIANG Guanlu;LIAO Yilai;DU Dengfeng;HUANG Haowei;LiUYong(School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory of High-speed Railway Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu ,Siehuan610031,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 [3]中国中铁二院工程集团有限责任公司,四川成都610031

出　　处：《岩石力学与工程学报》2019年第1期192-202,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51878577);铁道部科技研究开发计划项目(13164177);中国铁路总公司科技研究开发计划课题(2016G002–A)~~

摘　　要：通过开展相似比为1∶80的室内离心模型试验,并结合数值模拟方法,探究不同加固范围与不同边坡坡率对CFG桩–网复合地基受力变形特性的影响。分析表明:填筑期竖向位移明显增大,放置期与运营期增长缓慢并趋于稳定;当加固范围缩小时,边坡坡率为1∶1.5工况下的竖向位移增长趋势大于边坡坡率为1∶1.75工况下的,表现出边坡越陡对加固范围敏感性越高的规律;水平变形方面在坡脚及坡脚外5m位置处数值较大,当加固范围变化时坡脚处水平变形在土层交界面位置出现反弯点,且加固范围越小反弯程度越大;相同荷载作用下半加固复合地基桩顶应力大于全加固复合地基,桩间土应力则表现出相反的规律;边坡坡率相同时桩–土应力比随加固范围缩小表现出一定程度的增大。In order to study the effect of the strengthening area and the slope rate on bearing and deforming behaviors of CFG pile composite foundations,centrifuge test with a similarity ratio of 1∶80 and numerical simulation were conducted. The results show that the vertical displacement has a significant increase during embankment fill period and a slow growth during the placement and operation periods. With decreasing the strengthening area,the increasing trend of the vertical displacement with a slope ratio of 1∶1.5 is greater than that of 1∶1.75,which indicates that a steeper slope results in more sensitivity of the strengthening area. The horizontal displacements at the toe of the slope and 5 meters away from the toe of the slope are greater than those at other places. When the strengthening area decrease,a anti-bend point of the horizontal displacement at the toe of the slope occurs at the soil interface,and the anti-bend rate increases with decreasing the strengthening area. Under the same load,the stress on the pile top in a half strengthening composite foundation is greater than that in a whole strengthening composite foundation,but the earth stress between piles shows a opposite pattern. The pile-soil stress ratio shows a increase trend with the decrease of the strengthening area with a same slope rate.

关 键 词：桩基工程 离心模型试验 数值仿真 桩-网复合地基 受力变形特性 

分 类 号：TU47[建筑科学—结构工程]