岩溶地区深基坑地下水控制研究  

Study on groundwater control of deep foundation pit in karst area

作　　者：刘动 李韵迪 方润林 林国浮 Liu Dong;Li Yundi;Fang Runlin;Lin Guofu(Shenzhen Comprehensive Geotechnical Engineering Investigation&Design Co.Lid,Shenzhen 518172,China;Shenzhen Longgang Geology Bureau,Shenzhen 518172,Chin)

机构地区：[1]深圳市岩土综合勘察设计有限公司,广东深圳518172 [2]深圳市龙岗地质勘查局,广东深圳518172

出　　处：《工程勘察》2022年第10期48-53,共6页Geotechnical Investigation & Surveying

基　　金：广东省深圳市地质局地质工程院士工作站专项经费资助项目(No.2013B090400025)。

摘　　要：地下水控制是基坑工程能否成功的关键,灰岩地区各地层水力联系错综复杂,岩溶强发育条件下的深基坑地下水控制问题亟待解决。本文以深圳龙岗地区某深基坑工程为例,详细探讨了岩溶地区复杂水文地质条件下深基坑地下水控制的原则与措施,通过现场抽水试验并结合基坑开挖过程中地下水水位变化的实际监测数据,验证了本工程中岩溶地质条件下所采取的地下水控制措施的合理性和有效性。根据抽水试验和监测数据分析表明:本研究采取咬合桩并增设旋喷桩加固薄弱部位等止水措施后,坑内外水力联系较弱,截水帷幕截水效果较好。由于基坑底部普遍存在强透水层,层底承压裂隙岩溶水丰富,与上部砂土层孔隙水存在一定的水力联系,除采取上述止水措施外,部分区域在施工中还采用了旋喷桩封底隔渗加强措施。结合基坑整个开挖过程中第三方监测数据可知,所有的地下水水位监测点累计下降最大值不超过1.5m,地表沉降以及周边建筑物沉降均未超预警值,可以认为本研究所采取的地下水控制措施是合理且有效的。The groundwater control is the key to the success of foundation pit engineering. It has a complex hydraulic connection in karst area, and the groundwater control of foundation pit engineering in karst area is needed to be solved. Taking the deep foundation pit in Longgang district of Shenzhen as an example, the principles and measures of groundwater control under the complicated hydro-geological conditions in karst area are discussed. These measures have been verified reasonable and effective by the pumping tests and the actual monitoring data of groundwater level during the foundation pit excavation process. The pumping test results and the monitoring data show that the hydraulic connection inside and outside the deep foundation pit is weak and the sealing structure has a good effectiveness as the secant piles are reinforced by using the churning piles. The deep foundation pit has a good pervious layer on the bottom, and the pore water in the sand layer has a hydraulic connection with the confined fracture water on the bottom. It is suggested that the bottom should be closed by the churning piles in local area. Combining the monitoring data in the whole excavation process, the cumulative decline value of the underground water level is not more than 1.5 m, and the warning value of the ground surface settlement and the building settlement nearby is not exceeded. It could be assumed that the control measures of the underground water in the project are reasonable and effective.

关 键 词：岩溶强发育 深基坑 抽水试验 基坑监测 地下水控制 

分 类 号：TU196[建筑科学—建筑理论]