北京地铁工程中复合降水技术的开发应用

地铁工程施工不论是明挖、还是暗挖,从开挖的安全性及防水措施等方面,对地质均提出了非常严格的要求,地铁工程一般埋深较大,尤其在水文地质、工程地质条件较复杂的条件下,单一、简单的降水方法很难较好的满足地铁工程施工对地下水控制的要求。因此,需要考虑将不同种的单一降水方法中的优势技术进行合理叠加,尝试复合降水技术,能使地铁工程降水效果达到疏干充分、消除或有效控制含水层底界滞留水渗漏,避免拱顶因地下水渗漏造成冒顶、侧壁地下水渗漏造成坍塌,保障正常施工。

The Development and Application of the Composite Dewatering Technology in Subway Projects of Beijing

Due to the particularity of subway projects,strict demands are made on groundwater con- trol in terms of excavation security and water proof construction,both in open cut and undermining. Subway projects are generally operated at great buried depths.Especially,under complicated hydrogeologic and engineering geologic conditions,single and simple dewatering methods can hardly meet the demands of subway projects on groundwater control.Therefore,it is necessary to consider a rational combination of the optimum techniques of various single dewatering methods.The use of the composite dewatering technology may enable us to realize complete dewatering as well as removal or effective control of occluded water seepage on the aquifer floor,to avoid roof fall of the arch top and wall collapse resulting from groundwater seepage,thereby ensuring the normal operations. This paper discusses the development and application of the composite dewatering technology based on a summation of the dewatering achievements of industrial and civil foundation pits in the Beijing area as well as those of Beijing's undergoing subway projects.