临江深厚砂卵石地层沉管隧道干坞深基坑地下水控制方法研究  

Study on groundwater control method for deep excavation of dry dock in deep sandy cobble strata nearby river

作　　者：曾波存 岳新兴 周兴涛 孙晓伟[1] 桂大洪 Zeng Bocun;Yue Xinxing;Zhou Xingtao;Sun Xiaowei;Gui Dahong(CCCC Second Harbour Engineering Co.,Ltd.,Wuhan 430040,China;School of Civil Engineering and Architecture,Hubei University of Arts and Science,Xiangyang 441053,China;Xiangyang Hydrology and Water Resources Survey Bureau,Xiangyang 441003,China)

机构地区：[1]中交第二航务工程局有限公司,武汉430040 [2]湖北文理学院土木工程与建筑学院,湖北襄阳441053 [3]襄阳市水文水资源勘测局,湖北襄阳441003

出　　处：《工程勘察》2022年第9期39-44,78,共7页Geotechnical Investigation & Surveying

基　　金：中国交通建设股份有限公司科技研发项目(2018-ZJKJ-17);湖北省自然科学基金项目(2021CFB153)。

摘　　要：襄阳汉江沉管隧道西汊轴线干坞基坑占地面积大、暴露时间长,基坑底板处于深厚强透水的砂卵石地层内,场地地下水位高,干坞基坑地下水控制难度大。根据现场抽水试验、水文地质勘察及精细数值模拟方法,反演得到场地卵石层渗透系数为52.9m/d、圆砾层渗透系数为21.2m/d、粉细砂层渗透系数为10.4m/d。基于相关的基坑降水规范,并辅助精细化三维水文地质数值模拟方法,对该基坑降水方案开展了优化设计。经计算可得,西汊干坞深基坑降水井总深度为30.0~35.0m,总数量为305口,其中包括9口观测井,估算的基坑总涌水量Q为36.3×10^(4)m^(3)/d。现场监测表明,实际降水运行阶段深基坑处地下水位小于安全允许值,深基坑降水优化设计方案有效,实现了地下水位的有效控制。The excavation pit of the west branch dry dock for the Hanjiang immersed tunnel in Xiangyang covers a large area and expands a long exposure time.The bottom of the deep excavation locates in the highly permeable sand and cobble strata.The groundwater level of the site is high,so that the groundwater control is difficult and costly during the deep excavation.According to the field pumping test,hydrogeological survey and fine numerical simulation,the results show that the permeability of the cobble stratum is 52.9 m/d,the rounded gravel stratum is 21.2 m/d,the silty sand stratum is 10.4 m/d.Based on the relevant dewatering standard,and assisted with the refined three-dimensional hydrogeological numerical simulation method,an optimized dewatering scheme of the dry dock deep excavation was carried out.According to the calculation,the total depth of the west branch dry dock dewatering wells is 30.0~35.0 m,and 305 nos.of wells need to be constructed,including 9 nos.of observation wells.The estimated total water inflow Q of the pit is 36.3×10^(4)m^(3)/d.The monitoring data show that in the actual dewatering operation stage,the groundwater level was always below the allowable safe level.The dewatering design scheme of the deep excavation is successful,and the control target of the groundwater level was achieved.

关 键 词：干坞深基坑 地下水控制 砂卵石地层 降水试验 数值模拟 自动化监测 

分 类 号：TU463.3[建筑科学—结构工程]