磁浮线保护区深基坑降水技术研究  

Research on dewatering technology for deep foundation pit in Maglev Line protection area

作　　者：李洪运 LI Hongyun(Shanghai Municipal Engineering Design Institute(Group)Co.,Ltd.,Shanghai 200092,China)

机构地区：[1]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《地基处理》2025年第2期177-184,共8页Journal of Ground Improvement

摘　　要：在城市综合交通枢纽区域进行地下工程施工,如何有效控制深层地下承压水产生的影响,已成为上海软土地区超深基坑施工中必须解决的一个关键技术难题。超深基坑土方开挖引起的围护墙体位移,会导致周边设施产生不可避免的沉降,如果基坑内外的深层承压水无法完全隔断,那么开挖期间承压水位的降低对于坑外重要设施会产生非常不利的影响。上海机场联络线浦东机场站工程位于上海浦东机场综合交通枢纽主干道(迎宾大道)正下方,项目基坑范围内受古河道切割影响,南北地质与水文条件差异较大,其中⑥层和⑧层土缺失,⑦层和⑨层承压水联通,车站围护结构距离上海市磁悬浮线结构桩基仅为26 m,周边环境保护要求极高。为满足基坑与环境双重安全,文章针对复合承压含水层选择围护+降水综合设计,通过降水试验、理论模拟分析,首先进行初步结论验证,其次在施工降水阶段,通过按需降水、自动化监测、抽灌一体化等具体措施,最大化减少坑外水位降低幅度,最终实现了基坑安全以及周边环境保护的双重目标。Effectively controlling the impact of deep confined groundwater during underground construction in urban comprehensive transportation hub areas has become a key technical problem that must be solved in ultra-deep foundation pits in soft soil areas of Shanghai.The displacement of retaining walls caused by excavation will inevitably lead to settlement of surrounding facilities.If the deep confined groundwater between inside and outside the foundation pit cannot be completely separated,the decrease in the confined water level during excavation will have an very adverse impact on important facilities outside the pit.The Pudong Airport Station project of the Shanghai Airport Link is located directly beneath Yingbin Avenue,the main thoroughfare of the Pudong Airport comprehensive transportation hub.The foundation pit excavation area of the project is affected by the cutting of ancient river channels,resulting in significant differences in geological and hydrological conditions from north to south.The soil layers⑥and⑧are missing,and the confined groundwater in layers⑦and⑨is connected.The distance between the station’s retaining structure and the pile foundation of the Shanghai Maglev Line is only 26 meters,and the surrounding environment has extremely high protection requirements.In order to meet the dual safety of foundation pit and environment,this study adopts a comprehensive design combining retaining structures and dewatering for the composite confined aquifer.Through dewatering experiments and theoretical simulation analysis,preliminary conclusions were first verified.Then,specific measures such as demand-based dewatering,automatic monitoring,and integrated pumping and irrigation were taken to minimize the extent of water level reduction outside the pit during the construction dewatering phase.Finally,the dual objectives of foundation pit safety and surrounding environmental protection were successfully achieved.

关 键 词：承压水 深基坑 磁浮线沉降 降水 

分 类 号：TU47[建筑科学—结构工程]