摘要
针对CFG桩复合地基基坑开挖施工过程中的卸荷变形问题,依托某软土地区基坑工程,考虑CFG桩长、CFG桩间距、CFG桩布置形式等因素,采用有限元软件MIDAS GTS NX探究了不同工况下的复合地基承载特性问题。结果表明:CFG桩加固地基基坑开挖卸载下,CFG复合地基可显著抑制坑底回弹,隆起面略呈波浪状;桩身轴力的大小与工程桩在基坑平面中的位置有关,桩身轴力的分布呈现自基坑中心向两边逐渐减小趋势;桩体桩身弯矩随开挖深度变化曲线趋势基本同步,具有空间效应,CFG桩最大水平位移均出现在桩顶处;桩长设置为8m是该断面基坑的最佳情况,桩长过短则不利于控制CFG复合地基变形,过长则难以起到理想作用;CFG桩间距与基坑隆起数值、CFG桩桩顶的竖向变形量呈正相关关系;基坑变形对CFG桩的布置方式的敏感性较低。
Aiming at the unloading deformation of CFG pile composite foundation in the process of foundation pit excavation,relying on the foundation pit engineering in a soft soil area,considering the factors such as CFG pile length,CFG pile spacing and CFG pile arrangement,the bearing characteristics of composite foundation under different working conditions are studied by using finite element software MIDAS GTS NX.The results show that CFG composite foundation can significantly restrain the rebound of pit bottom and the uplift surface is slightly wavy under the condition of foundation pit excavation and unloading.The axial force of the pile body is related to the position of the engineering pile in the plane of the foundation pit,and the distribution of the axial force of the pile body gradually decreases from the center of the foundation pit to both sides,and the variation curve of the bending moment of the pile body with the excavation depth is basically synchronous,which has a spatial effect.The maximum horizontal displacement of CFG pile appears at the top of the pile.The best condition of the foundation pit of this section is that the pile length is set to 8m.If the pile length is too short,it is not conducive to control the deformation of CFG composite foundation,and if it is too long,it is difficult to play an ideal role;the distance between CFG piles is positively correlated with the uplift value of foundation pit and the vertical deformation of CFG pile top;the sensitivity of foundation pit deformation to the arrangement of CFG piles is low.
作者
张岗平
毛立华
顾文超
唐晓宇
ZHANG Gangping;MAO Lihua;GU Wenchao;TANG Xiaoyu(Power China Huadong Engineering Corporation Limited,Hangzhou 311100,China;College of hohai Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《建筑结构》
北大核心
2023年第S02期2308-2313,共6页
Building Structure
基金
中国电建集团华东勘测设计研究院有限公司科研项目(KY2021-JG-03-41)。
关键词
CFG桩
基坑
隆起位移
桩顶变形
CFG桩桩身弯矩
CFG pile
foundation pit
uplift displacement
pile top deformation
CFG pile body bending moment
作者简介
第一作者:张岗平,学士,高级工程师,主要从事水工岩土工程研究,Email:zhang_gp@hdec.com。
