摘要
针对异形深基坑几何突变引发的应力梯度剧变与支护体系协同机制不明确问题,本文以天津市河北区红星桥泵站异形深基坑工程为背景,通过三维精细化数值模拟与现场监测,揭示了灌注桩-止水帷幕支护体系的力学响应规律。研究表明:L形箱涵转角区灌注桩桩底应力达40.2 MPa,为该基坑应力最低点的3.2倍,印证了基坑角度转折造成的应力突变现象;灌注桩桩底应力在转角区应力变化率达0.47 MPa/m,为主基坑直线段的4.7倍,表明异形边界显著放大应力梯度。灌注桩桩底应力在几何突变区的实测值对模拟值的全部数据偏差均不超过10%,周边地表沉降实测值对模拟值的全部数据偏差均不超过15%,证实三维实体单元建模对异形深基坑支护体系力学响应的精准表征。研究成果为异形深基坑支护设计提供了几何形态修正系数与量化理论支撑,具有显著工程应用价值。
In response to the unclear issue of stress gradient changes caused by geometric mutations in irregular deep foundation pits and the collaborative mechanism of support systems,this paper takes the irregular deep foundation pit project of the Hongxingqiao Pumping Station in the Hebei District of Tianjin as the background.Through three-dimensional refined numerical simulation and on-site monitoring,it reveals the mechanical response laws of the reinforced concrete pile water-stop curtain support system.The study shows that the bottom stress of the L-shaped box culvert turning area reaches 40.2 MPa,which is 32 times the lowest stress point of the foundation pit,confirming the phenomenon of stress mutation caused by the angle changes of the foundation pit.The stress change rate at the bottom of the pile in the turning area reaches 0.47 MPa/m,which is 4.7 times that of the linear segment of the main foundation pit,indicating that the irregular boundary significantly amplifies the stress gradient.The measured values of the bottom stress of the pile in the geometric mutation area show that all data deviations from simulated values do not exceed 10%,and the measured values of surrounding surface settlement do not exceed 15%,confirming the accurate representation of the mechanical response of the irregular deep foundation pit support system through three-dimensional entity element modeling.The research results provide geometric correction coefficients and quantitative theoretical support for the design of irregular deep foundation pit supports,which has significant engineering application value.
作者
张刚
ZHANG Gang(China Railway 18th Bureau Group 5th Engineering Co.Ltd.,Tianjin 300459,China)
出处
《铁道建筑技术》
2025年第7期158-161,214,共5页
Railway Construction Technology
基金
中铁十八局集团有限公司科技研究开发计划课题(0-QT-2024-科技部-0-017)。
关键词
异形深基坑
灌注桩
止水帷幕
基坑支护
力学响应
irregular-shaped deep foundation pit
bored pile
water-stop curtain
foundation pit support
mechanical response
作者简介
张刚(1992-),男,河北张家口人,工程师,主要研究方向为工程施工技术,E-mail:2581445160@qq.com。
