复杂环境下地铁车站PBA工法施工降水

Dewatering Technology of PBA Metro Station under Complex Environment

地铁车站修建过程中存在临近建筑物、管线密集复杂、地下水丰富的特点。为解决地铁车站PBA工法施工需在无水环境下作业,又不能过度占用地面空间和影响周边环境的问题,针对北京地铁17号线十里河地铁车站所处的复杂环境,采用一种以洞内轻型井点为主、地表真空管井为辅,与PBA工法有效结合的综合降水方法。降水效果表明:1)地面管井有效地控制了各层地下水水位,确保了竖井正常施工;2)水平辐射井作为施工横通道和导洞开挖的主要降水方法,有效地降低了开挖范围内承压水等水量较大的地下水水位,确保了PBA工法施工处于无水环境;3)斜井作为洞内辅助降水施工手段,处理了层间潜水和界面残留水。

The construction of metro station has characteristics such as adjacent buildings,dense pipelines and rich groundwater.In order to solve the construction problem PBA metro station without water,the limit ground area and surrounding environment,a comprehensive dewatering method combined with PBA method is used in Shilihe Metro Station on Beijing Metro Line No.17 in complex environment,and the light well point in tunnel as main mean and vacuum tube on ground as assistant are adopted.The dewatering effects show that:(1)The ground tube well effectively controls the groundwater level of each layer to ensure the normal construction of the vertical shaft.(2)The horizontal radiation wells,as the main precipitation method for construction cross passageway and pilot tunnel excavation,effectively reduces the groundwater level with large water volume such as confined water within the excavation range,which provides a water-free environment for PBA station.(3)The inclined shaft is used as an auxiliary dewatering construction method in tunnel to dewater the inter-layer diving and interfacial residual water.