论堤防管涌的危急性及其分类的意义

通过回顾荆江大堤的管涌实例和已经围绕管涌开展的模型模拟研究工作,得到了一系列启示;建立了管涌危急性和致溃型管涌概念,并分别展开了讨论,认为管涌危急性概念的提出有利于开展各影响因素对管涌规律作用的定量研究;对管涌危急性具有特殊影响的因素包括洪水过程、堤内水位、管涌位置、管涌附近及其扩展路径上的地层结构条件和土体性质、渗流控制措施等;根据危急性对管涌进行分类,是管涌分类施策的重要基础,也是提高管涌险情处置针对性与科学性的重要途径。一般情况下,可以将堤身管涌,以及管涌扩展过程没有收敛迹象、短期内可能扩展至堤身附近的堤基管涌划归为致溃型管涌,需要立即采取抢险处置措施遏止其进一步演化,或者立即启动应对决堤的预案。

On the Criticality of Piping and the Significance of Its Classification

The concepts of piping’s criticality and piping tending to breach dyke were presented in the light of some cases of piping happened in the Jingjiang stretch of Yangtze River dyke and the studies of piping modelling. The concept of piping’s criticality is conducive for the quantitative research on factors affecting piping’s evolution. Special influence factors on criticality of piping include: flood process, water level in the protected area, piping’s location, structure and soil properties near the piping and along its evolution path, as well as seepage control measures. Classifying piping according to criticality lays an important foundation for the separate treatment of different piping types,and is also a vital approach to improving the pertinence and scientific decision of piping treatment. Generally, piping in the embankment, and those extending fast to the embankment, should be recognized as piping tending to breach dyke, which should be followed with treatment measures to hinder the evolution, or emergency plans implemented immediately.