(1 南通城市轨道交通有限公司, 南通 226000; 2 同济大学土木工程学院, 上海 200092)

摘要: 以富水砂性地层顺作法地铁车站基坑为工程背景,结合施工现场监测数据,对围护结构侧向位移变形、周边地表沉降、地下水水位变化及周边建筑物沉降进行分析,总结富水砂性地层的变形性状和对周边环境的影响.监测数据和分析结果表明:富水砂性地层条件下,地下连续墙最大侧向位移 δhm 的变化范围为 0. 045%H~ 0. 5%H,均值约为 0. 22%H,发生位置在(H-4,H+10)之间;基坑开挖引起的地表沉降影响范围在 35m 以内,约 2 倍基坑开挖深度;墙后地表最大沉降发生在距离基坑 5~ 10m 左右;富水砂性地层有着地下水位高,渗透性强的特点,施工中采用疏干降水与承压降水相结合的措施可以有效控制地下水位变化;施工建设过程中对周边建筑物进行实时监测来反馈指导施工, 可以保证施工对周边建筑物的影响在可控范围内.

关键词: 富水砂性地层; 地铁车站; 深基坑; 基坑降水; 变形; 监测

中图分类号:TU758. 11 文献标志码:A 文章编号:1002-848X(2023)12-0138-06

DOI:10. 19701 / j. jzjg. 20201613

Analysis on monitoring and deformation of subway deep foundation pit inwater-rich sand stratum

WAN Jing1, FAN Dongdong2, LIU Tianren2, TAN Yong2

(1 Nantong City Rail Transit Co. , Ltd. , Nantong 226000, China; 2 Department of Geotechnical Engineering, TongjiUniversity, Shanghai 200092, China)

Abstract: Taking the foundation pit of subway station with water-rich sand stratum as the engineering background, combinedwith the monitoring data on the construction site, the lateral displacement deformation of the enclosure structure, thesurrounding surface settlement, the groundwater level change and the settlement of surrounding buildings were analyzed tosummarize the deformation behavior of the water-rich sand stratum and its impact on the surrounding environment. Themonitoring data and analysis results show that: under the conditions of water-rich sand stratum, the maximum lateraldisplacement δhmof the diaphragm wall ranges from 0. 045%H to 0. 5%H, with an average value of about 0. 22%H,and theoccurrence is between (H-4, H+10). The impact of surface settlement caused by excavation of foundation pit ranges within35m, about 2 times the excavation depth of the foundation pit. The maximum settlement of the surface behind the wall occursat a distance of about 5 ~ 10m from the foundation pit. The water-rich sandy stratum has the characteristics of highgroundwater level and strong permeability, and the combination of pumping in phreatic and confined aquifers can effectivelycontrol the change of groundwater level in construction; real-time monitoring of surrounding buildings during construction canguide construction, which ensures that the impact of construction on surrounding buildings is within a controllable range.

Keywords:water-rich sand stratum; subway statio; deep foundation pit; dewatering of foundation pit; deformation; monitoring

第一作者:万晶,博士,工程师,主要从事基坑工程方面的研究,Email:706505658@ qq. com.

[引用本文] 万晶,樊冬冬,刘天任,等. 富水砂性地层地铁深基坑监测及变形分析[ J]. 建筑结构,2023,53(12):138-143. WAN Jing,FAN Dongdong,LIU Tianren,et al. Analysis on monitoring and deformation of subway deep foundationpit in water-rich sand stratum[J]. Building Structure,2023,53(12):138-143.