（1 上海同继水资源技术有限公司， 上海 200082； 2 中交路桥建设有限公司， 北京 100027）

［摘要］高水位地区深基坑工程实践中，多以止水帷幕辅以基坑降水的方式进行地下水的处理。场地水文地质参数的选取、降水方法的选择，以及止水帷幕是否达到良好止水效果等是关系到基坑降水成功与否的几个重要因素。莫桑比克马普托大桥南锚碇基坑直径50m，挖深超过36m，止水帷幕为地下连续墙，墙深56m。在地下连续墙嵌岩的情况下，基坑土方开挖实施过程中屡发承压水突涌事故，导致无法正常开挖施工。首先，通过在坑外进行抽水试验获取场地的水文地质参数，结合有限差分数值模拟软件，建立三维渗流模型，进行基坑渗流场的模拟，预测基坑施工过程中的水位变化情况，与实际坑外降水水位变化进行对比，验证三维渗流模拟计算的合理性与适用性。其次，基于三维渗流计算结果，采取坑内外同时降水的方式将基坑外部承压水水头控制在开挖面以下，使得基坑顺利实施。

［关键词］超深基坑； 降水； 三维渗流模拟

中图分类号： TU46+3 文献标识码： A文章编号：  1002-848X(2016)S2-0560-04

Three dimensional seepage simulation of groundwater in the application of ultra-deep foundation pit in Maputo Bridge

Yang Yingyi1, Guo Changrui2, Liu Jiang2

(1 Shanghai Tongji Water Resources Technology Co., Ltd., Shanghai 200082, China;2 Road and Bridge International Co., Ltd., Beijing 100027, China) 

Abstract: Waterproof curtain combined with dewatering are the usual method at the engineering practice in solving the groundwater. The selection of hydrogeology parameters, the method of dewatering and the effects of the waterproof curtain are all very important. South anchorage foundation pit of Maputo bridge, Mozambique, 50m in diameter, depth more than 36m, used diaphragm wall as waterproof curtain, and the depth of the wall is 56m, which was rock-socketed. Groundwater inrushing happened several times, which caused unable to do normal construction of foundation pit. Firstly, hydrogeology parameters obtained from pumping tests outside of the pit, combined with the finite difference numerical simulation software, are used to establish the three dimensional seepage model, to predict water level changes during the construction process, compared with actual pit precipitation water level change, validate the rationality of the three dimensional seepage simulation and applicability. Secondly, based on the calculated results, dewatering outside the excavation was used to avoid the dangerous of the water inrushing.

Keywords: ultra-deep foundation pit; dewatering; three dimensional seepage simulation