摘要
合理地设置缓冲区宽度是基坑群工程设计中需重点关注的问题。以上海软土地区典型基坑群工程为背景,采用基于小应变土体本构模型并考虑土与结构共同作用的三维有限元方法,研究了不同缓冲区宽度对同步开挖基坑群变形的影响规律。结果表明,缓冲区的宽度对中隔墙的变形形态有重要影响,当缓冲区宽度不大于1.5倍深度时,随着缓冲区宽度增加中隔墙的侧向位移最大值明显增大;缓冲区宽度对基坑群外围潜在滑裂面基本没有影响,但对缓冲区的潜在滑裂面发展影响很大;坑外地表沉降随着缓冲区宽度的增加而略有减小,受两侧分坑开挖叠加影响,缓冲区地表沉降最大值呈现出先增大后减小的趋势,当缓冲区宽度大于3倍挖深时,缓冲区地表沉降形态为具有两个峰值沉降点的“W”形。基于研究结果,建议设计时缓冲区宽度取不小于2倍的基坑开挖深度。
Reasonably setting the width of buffer zone is an important problem in the engineering design of excavation groups.Based on the typical deep excavation group in Shanghai soft soil area,the influence of different buffer widths on the deformation behavior of excavation group excavated simultaneously is studied by using the three-dimensional finite element method based on the small strain soil constitutive model and considering the interaction between soil and structure.Results show that:The width of the buffer zone has an important influence on the deformation form of the middle partition wall.When the width of the buffer zone is not greater than 1.5 times the excavation depth,the maximum lateral displacement of the middle partition wall increases significantly with the increase of the width of the buffer zone.The width of the buffer zone has little effect on the potential sliding surface around the deep excavation group,but has a great impact on the development of the potential sliding surface in the buffer zone.The surface settlement outside the pit decreases slightly with the increase of the width of the buffer zone.Affected by the superposition of pit excavation on both sides,the maximum surface settlement in the buffer zone increases first and then decreases.When the width of the buffer zone is greater than three times the excavation depth,the surface settlement in the buffer zone is in the shape of"W"with two peak settlement points.It is suggested that the width of the buffer zone should not be less than two times the excavation depth of the deep excavation.
作者
顾正瑞
徐中华
Gu Zhengrui;Xu Zhonghua(Shanghai Underground Space Engineering Design&Research Institute,East China Architecture Design&Research Institute Co.,Ltd.,Shanghai 200002,P.R.China;Shanghai Engineering Research Center of Safety Control for Facilities Adjacent to Deep Excavations,Shanghai 200002,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第S01期269-277,293,共10页
Chinese Journal of Underground Space and Engineering
关键词
基坑群
缓冲区
三维有限元
小应变
变形
excavation group
buffer
three-dimensional fin it element
small strain
deformation
