南京江北长江漫滩地层抽水回灌案例分析
1. 南京达西岩土工程有限公司, 江苏南京 210019
2. 中国葛洲坝集团第一工程有限公司, 湖北宜昌 443002
| 摘 要： | 南京江北新区某项目，在基坑开挖完成且底板浇筑后，基坑发生底板侧墙与地墙间隙涌水事故。此时基坑内2-4、2-5粉细砂层承压水观测井水位能够满足安全水位控制要求，根据分析涌水为深层的3-4e、3-4中粗砂层涌水。由于底板已经施工完成，难以在坑内处理。为解决坑内涌水问题，采取坑外降水措施，但降水导致旁边小区地面出现快速沉降，为减小地面沉降，特设计了回灌井，组织了回灌试验，优化回灌井结构、布置间距等问题根据试验成果进行抽水与回灌错层的方式，解决了坑外抽水与回灌相互回流的问题。最后成功的控制了沉降。本工程是在没有止水帷幕的条件下，同时在坑外进行降水及回灌，既解决了涌水，又控制了沉降，并且基坑深度大、涌水量大，过程中先通过分析，再进行试验，最终施工达到回灌目的。具有参考价值，故总结成文。 |
| 关 键 词： | 基坑涌水; 基坑降水; 回灌; 沉降控制 |
| DOI： | 10.57237/j.cear.2023.01.004 |
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收稿日期: 2023-03-14
接受日期: 2023-04-15
在线出版日期: 2023-04-25
Case Study of Pumping and Recharging in the Floodplain by Yangtze River in Jiang Bei Nanjing
1. Nanjing Darcy Geotechnical Co., Ltd, Nanjing 210019, China
2. Gezhouba Group No. 1 Engineering, Yichang 443002, China
| Abstract: | For a project in Nanjing Jiangbei New Area, after excavation of foundation pit and foundation plate pouring, water inrush between side wall of foundation plate and wall occurred in foundation pit. At this time, the water level of confined water observation wells in 2-4 and 2-5 silty fine sand layers in foundation pit can meet the requirements of safe water level control. According to the analysis, the inrush water is inrush water from 3-4e and 3-4 coarse sand layers in deep layer. It is difficult to treat the floor slab in the pit due to the completion of construction. In order to solve the problem of water inrush in the pit, the measures of precipitation outside the pit are adopted, but precipitation causes rapid settlement of the ground in adjacent areas. In order to reduce the ground settlement, a recharge well is specially designed, the recharge test is organized, the structure of the recharge well is optimized, and the spacing between the two layers is arranged according to the test results. The problem of recirculation between pumping and recharging outside the pit is solved. Finally, settlement was successfully controlled. Without water-stop curtain, the project carries out precipitation and recharge outside the pit at the same time, which not only solves the inrush water, but also controls the settlement. In addition, the foundation pit is deep and inrush water is large. During the process, the analysis is carried out first, and then the test is carried out, so that the purpose of recharge can be achieved. It has reference value, so it is concluded in writing. |
| Keywords: | Well-up Water; Foundation Pit Dewatering; Recirculation; Settlement Control |
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