Some Geologic Considerations for Grout Curtain Design

The objective of construction of a grout curtain ordinarily is to reduce seepage through dam foundations and, in some cases, through reservoir rims by means of sealing geologic defects that might provide leakage paths. “Cookbook” approaches to sealing those leakage paths, using some “standard” geometric pattern of grout holes, are widely used and may be successful where optimum conditions of width, distribution, and interconnection of potential seepage or leakage paths exist. However, Mother Nature isn’t always that cooperative. Therefore, an understanding of the site geologic conditions should be considered an essential part of designing a grouting program that will have the optimum opportunity to identify and intersect potentially open geologic defects and to treat them appropriately and effectively . An understanding of the site geologic conditions and their engineering implications also may be an essential part of a process in which it is decided that some remedial treatment other than, or in addition to, grouting may be appropriate.