复合地基对临近基坑稳定性影响的数值模拟研究  

Numerical Simulation Study on the Effect of Composite Foundation on the Stability of Adjacent Foundation Pit

作　　者：曾力[1] 蔡云鹏 李明宇[1] 杨潇 李玉涛 ZENG Li;CAI Yunpeng;LI Mingyu;YANG Xiao;LI Yutao(School of Water Conservancy and Civil Engineering,Zhengzhou University,Zhengzhou,China,450001;Wuhan Metro Group Co.Ltd.,Wuhan,China,430070;China Construction Communications Construction Group Co.Ltd.,Beijing,China,100071)

机构地区：[1]郑州大学水利与土木工程学院,河南郑州450001 [2]武汉地铁集团有限公司,湖北武汉430070 [3]中建交通建设集团有限公司,北京100071

出　　处：《沈阳建筑大学学报（自然科学版）》2023年第2期193-201,共9页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金青年项目(42107196)。

摘　　要：目的 基于已有基坑稳定性分析的建模方法,开展邻近复合地基深基坑变形与稳定性问题的精细化研究。方法 结合某基坑工程实例利用PLAXIS 3D软件建立三维数值计算模型,分析支护桩水平位移、基坑稳定性系数、基坑滑裂面位置与状态等不同变形特征参数对基坑性状的影响,进而研究既有建筑复合地基桩体条件变化对基坑稳定性的影响。结果 邻近复合地基的基坑稳定性系数均大于桩基础和天然地基,且支护桩水平位移峰值较天然地基减小40%;复合地基和桩基下的基坑滑裂面形态大致相近,均从基础中部向基坑底部延伸;CFG桩桩长在超过1倍开挖深度、桩径超过0.7 m及桩体刚度达到500 kPa后,滑裂面与地表的交点位置不再变化,复合地基与临近基坑距离超过1倍开挖深度后,对基坑影响可以忽略不计。结论 提出邻近复合地基的基坑整体稳定性系数优于桩基础和天然地基,CFG桩桩长、桩径、桩体模量和临近基坑距离的变化均对基坑开挖呈有利作用等影响规律,结果可供工程实际应用参考。Based on the existing modeling methods of foundation pit stability analysis,a detailed study on the deformation and stability of deep foundation pit adjacent to composite foundation is carried out.A three-dimensional numerical calculation model was established based on the foundation pit project in Zhengzhou,and the influence of different deformation characteristic parameters,such as the horizontal displacement of retaining pile,the stability coefficient of foundation pit,the position and state of sliding surface of foundation pit,on the behavior of the foundation pit was analyzed,and then the influence of pile conditions of existing building composite foundation on the stability of the foundation pit was studied.Results show that the stability coefficients of foundation pit adjacent to composite foundation are greater than those of pile foundation and natural foundation,and the peak value of horizontal displacement of retaining pile is 40%less than that of natural foundation;the sliding surface of foundation pit under composite foundation and pile foundation is similar,extending from the middle of foundation to the bottom of foundation pit;when the length of CFG pile exceeds one time of the excavation depth,the pile diameter exceeds 0.7 m,and the pile rigidity reaches 500 kPa,the intersection position between the sliding surface and the ground will not change.When the distance between composite foundation and the adjacent foundation pit exceeds one time of the excavation depth,the impact on the foundation pit can be ignored.So the stability coefficient of foundation pit adjacent to composite foundation is better than that of pile foundation and natural foundation.All the changes of CFG pile length,diameter,pile modulus and distance from the foundation pit are beneficial to foundation pit excavation.

关 键 词：基坑工程 复合地基 基坑稳定性 滑裂面 数值模拟 

分 类 号：TU472[建筑科学—结构工程]