城际铁路新郑机场站基坑工程降水设计与施工

郑州至新郑机场城际铁路新郑机场站工程基坑开挖范围内地层条件复杂，砂性土与粘性土互为透镜体，开挖范围内主要为粉土、粉砂、粉质粘土，属黄土类地层，渗透性能差，若降水井施工质量差，抽不出水且容易带走细颗粒，开挖时又容易发生流砂。对此类复杂地层的降水设计应充分考虑地层条件、围护结构的特性，保证将水位降至开挖面以下，同时避免流砂、管涌、突涌的发生，确保基坑开挖安全。在采用三维数值模拟分析场区水文地质渗流情况的基础上，进行降水设计，并采取有效的降水井施工技术措施，实践证明取得了良好的降水效果。

Design and Construction of Foundation Pit Dewatering in an Intercity Railway Station of Zhengzhou

The formation conditions are complex in an intercity railway station of Zhengzhou to Xinzheng, lens of sandy soil and cohesive soil exist interacted.The excavation range is in poor permeable loess formation with silt, silty sand silty clay, so the dewatering well construction quality is very important.The formation conditions and characteristics of enclosure struc-ture should be fully considered in dewatering design to ensure water level lowering below the excavating surface and avoid the sand flow, piping and gushing.The dewatering scheme is designed on the baisis of the analysis on hydrogeology seepage in the field by 3D numerical simulation, and with the effective dewatering construction measures being used, good dewate-ring effect has been proved by practice.