摘要
为研究基坑开挖施工时邻近桩基的力学特性及变形,基于北京大兴国际机场地下综合管廊下穿共构桥梁工程,运用数值模拟手段,在验证所建模型合理性的基础上分析了基坑开挖施工时桩顶自由与固定时的桩身变形特征,进一步研究了不同开挖深度、桩与围护结构距离、开挖土体参数以及桩径等因素对邻近桩基侧向变形产生的影响。研究表明:当桩顶固定时,桩基最大侧向位移会大幅度减小;桩基侧向变形受基坑开挖深度影响较大,北京地区基坑采用悬臂式支护开挖时,建议深度不超过6.2m;桩基最大位移和桩与围护结构的距离呈负指数关系;邻近桩基的侧移随着土体弹性模量和黏聚力增大而减小;桩径与桩身柔度密切相关,桩身最大侧向位移与桩径的平方(即柔度)呈负线性关系。
In order to study the mechanical characteristics and deformation displacement of adjacent pile foundation during foundation excavation, based on the underground utility tunnel of Beijing Daxing International Airport, this paper uses numerical simulation to verify the rationality of the model, analyzes the deformation characteristics of pile body at the free and fixed time of pile top during foundation excavation, and further analyzes the different excavation depth, the distance between pile and retaining structure, the influence of excavation soil parameters and pile flexibility on adjacent pile foundations. The research shows that when the pile top is fixed, the maximum lateral displacement of the pile foundation will be greatly reduced, and the lateral deformation of the pile foundation will be greatly affected by the excavation depth of the foundation excavation. When the cantilever support is used for the foundation excavation in Beijing, the depth should generally not exceed 6.2 m. The maximum displacement of the pile foundation has a negative exponential relationship with the distance between pile and retaining structure, and the lateral displacement of the adjacent pile foundation decreases with the increase of the elastic modulus and cohesion of the soil. The pile diameter is closely related to the pile flexibility, and the maximum lateral displacement of the pile has a negative linear relationship with the square of the pile diameter(i.e. flexibility).
作者
赵腾跃
梁胜
候捷
张晨
卞海丁
姚伟伟
ZHAO Tengyue;LIANG Sheng;HOU Jie;ZHANG Chen;BIAN Haiding;YAO Weiwei(Beijing Municipal Road and Bridge Co.,Ltd.,Beijing 100045,China;School of Highway,Chang’an University,Xi’an,Shaanxi 710064,China)
出处
《施工技术（中英文）》
CAS
2022年第19期40-45,共6页
Construction Technology
基金
北京市政路桥集团科技创新项目(LQKJ-2018-11-01)。
关键词
基坑
邻近桩基
侧向变形
开挖深度
数值模拟
foundation excavation
adjacent pile foundation
lateral deformation
excavation depth
numerical simulation
