摘要
针对红粘土上硬下软地层中开口管桩上浮问题,分别进行了三类不同桩径的开口管桩室内沉桩模型试验,研究单桩和群桩静压沉桩试验中上浮量变化规律和土塞效应对开口管桩上浮的影响。结果表明:单桩上浮量主要由静压沉桩引起的管桩弹性压缩经卸荷回弹产生的变形提供;群桩静压上浮与施工顺序、桩间距以及位置有关,先压入的管桩上浮量大于后压入的管桩上浮量,且先压入桩的上浮速度随着后压入桩的桩间距减小而增加;桩位对桩上浮的影响强度顺序由高到低依次是中心桩位、边桩位、角桩位;当开口管桩从硬塑层压入至可塑层一定深度后,由于土塞完全闭塞的影响,导致挤土效应增强,有别于闭口管桩静压至在软硬交界面处出现的短暂上浮量增长休止的状况,开口管桩群桩挤土上浮量表现出显著上升趋势。
In order to solve the floating problem of open-ended pipe piles in the red clay layer that is hard in upper part and soft in lower part,three groups of indoor pile-sinking model tests were carried out on open-end pipe piles of different diameters,and the change rule of floating quantity and the effect of soil plug effect on the floating of open-ended pipe pile in single pile and group pile static pressure pile driving test was studied. The results show that the floating volume of single pile is mainly provided by elastic compression of pile under static pressure and unloading rebound. The floating of the pile group static pressure is related to the construction order,the pile spacing and the position of pipe pile. The floating amount of the first pressed pipe pile is greater than that of the post pressure pipe pile,and the upward floating velocity of the first pressed pile increases with the decrease of the pile spacing of the post pressure pile. The order of the influence of the pile position on the floating of the pile is the center pile position,the side pile position and the angle pile position. When the open-ended pile group is pressed from the hard plastic layer into the plastic layer,the squeezing effect enhanced due to the soil plug closed,and the floating amount of openended pile had a significant upward trend,which was different from the closed-ended pile group whose floating growth would temporarily stop.
作者
王家全
叶斌
黄柳云
张昊
Wang Jiaquan;Ye Bin;Huang Liuyun;Zhang Hao(College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2018年第5期1226-1233,共8页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(51469005)
广西自然科学基金(2015GXNSFAA139257
2015GXNSFAA139270
2017GXNSFAA198170)
广西研究生教育创新计划项目(YCSW2018201)
关键词
红黏土地层
开口桩
土塞效应
模型试验
red clay soil layer
open-ended pile
soil plug effect
model test
