超厚粉细砂层深基坑钢板桩围堰施工及多重排水方案研究

Research on Construction and Multiple Drainage Schemes of Steel Sheet Pile Cofferdam for Deep Foundation Pit in Ultra Thick Fine Sand Layer

淮河特大桥跨北淝河(75+128+75)m连续梁34#、35#主墩位于北淝河两侧河滩处,水深约1~3.5m。受淮河早期冲积影响,下伏地层主要为稍密~中密粉细砂层,砂层厚度约20~30m。该桥现场采用筑岛+钢板桩围堰施工工艺,由于粉细砂层透水性较强,施工过程中存在渗漏水、排水困难等难题。本文以淮河特大桥34#承台为例,结合现场施工经验,介绍淮河流域超厚粉细砂层深基坑钢板桩围堰施工技术以及现场采取明沟、暗沟相结合的多重排水方案,希望能为类似工程施工提供参考。

The 34#and 35#pier columns of a continuous beam spanning(75+128+75)m across the North Fei River of Huaihe River Bridge are located at the riverbanks on both sides of the North Fei River,with a water depth of approximately 1-3.5m.Affected by the early alluvial deposits of the Huaihe River,the underlying strata are mainly slightly to moderately dense fine sand layers,with a thickness of about 20-30m.The bridge adopts the construction process of island building and steel sheet pile cofferdam,but due to the strong permeability of the fine sand layer,there are problems such as water leakage and drainage difficulties during the construction process.Taking the 34#bearing platform of the Huaihe River Extra Large Bridge as an example,based on on-site construction experience,this article mainly introduces the construction technology of steel sheet pile cofferdam for deep foundation pits in the Huaihe River Basin with ultra-thick and fine sand layers,as well as the multiple drainage schemes combining open and hidden ditches.It is hoped that this can provide reference for similar engineering construction.