基岩渗漏成因病险堤坝的两个典型实例

介绍了两个因下伏基岩渗漏而引起病险堤坝工程地质问题的典型实例－北江大堤石角段断层型堤基渗漏及其引起的渗透变形和黄壁庄水库副坝覆盖型岩溶坝基渗漏及其引起的坝体大规模塌陷。通过人工同位素示踪和天然示踪、环境同位素、水化学分析以及地层密度等的测定发现：北江大堤石角段下伏基岩中存在北东向强透水断层，是历年洪水期发生险性的直接原因，应用平面热源原理进一步确定了该断层在空间上是基本平直向北西倾斜的：基岩溶洞的存在是黄壁庄水库副坝塌陷的客观地质基础，不适当的防渗加固施工方法是黄壁庄水库副坝塌陷的直接诱因。

TWO TYPICAL EXAMPLES OF DYKES WITH DEFECTS OR IN DANGER RESULTED FROM BED ROCK PERMEATION

This article presents two typical examples of engineering geological problems in dykes with defects or in danger resulted from permeation through the underlying bed rock: fault-typed permeation at dyke foundation in Shijiao Section of Beijiang River Dyke and the resulted osmotic deformation, the covering type of karst dyke foundation permeation in the auxiliary dyke of Huangbizhuang Reservoir and the resulted large-scale collapse of the dyke body. It has been found in artificial isotopic tracing, natural tracing, in environment isotopic and water chemical analysis, and in the determination of ground layer density, that there is a severe water-permeating fault of NE strike in the underlying bed rock of Shijiao Section of Beijiang River Dyke, which is directly related to the dangers during the flood seasons for years. It has been further determined by applying the plane thermal source principle that this fault is basically flat and straight in space and is dipping to NW. Bed rock karst is the objective geological foundation of the collapse of the auxiliary dyke of Huangbizhuang Reservoir, and improper construction method for anti-permeation consolidation is the first direct inducing cause to the collapse.