长江口软土地基水库围堤的防渗体结构探讨

Impervious structure of reservoir embankment in soft soil foundation of Yangtze Estuary

充泥管袋充填粉细砂技术,在长江口软土地基上修筑围堤,取得了较好的效果。但围堤堤身均由透水性较强的粉砂料填筑而成,且围堤堤基浅部地层通常分布有粉土、粉砂土,属中等透水且易产生渗透变形。在库内外水头差的作用下,堤身、堤基土均可能产生渗漏及渗透变形问题,因此,水库围堤必须要采取渗流控制处理措施。结合本工程渗流控制措施的特点和难点,进行了多方案比选,并根据现场原型试验确定防渗体结构的最终结构形式和施工参数。还对推荐方案进行了详细的渗流控制分析计算,为类似工程提供参考。

The technology of mud-filled bag filled with sand plays a good role in the construction of the dike in the Yangtze Estuary. However, the dike embankments are mainly built by powder materials with high permeability, and the shallow strata of dike foundation normally consist of silt and silty sand, which are moderately permeable and prone to seepage deformation. Under the action of water head difference, levee and foundation soil may produce leakage and seepage deformation. Therefore, seepage control measures should be taken for the reservoir embankments. According to the characteristics and difficulties of the seepage control measures in this project, many schemes are compared, and the final form and construction parameters of the impervious structure are determined based on the field prototype tests. A detailed calculation of the flow control of the recommended scheme is given, and it may can provide reference for similar projects.