A Retrospective on the History of Dam Foundation Grouting in the U.S.

The history of dam foundation grouting in the U.S., which began with a project in New York in the late nineteenth century, is—to some extent—one of objectives not fully achieved. It also is one of innovative procedures and insightful ideas only some of which were applied, and of questionable procedures that look all too familiar to today's grouting practitioners. An early suggestion that a closely adjacent two-row grout curtain consisting of closely-spaced grout holes might be preferable to a three-row curtain clearly was not incorporated in the design of Teton Dam, but has been incorporated in the design of a few dams constructed in recent years. The early twentieth century concept of injecting essentially endless volumes of high w:c ratio grouts survived unto the late twentieth century, despite a realization in some quarters that such grout would travel far beyond the area requiring treatment and would either not set up at all or would merely form "films." By the time Boulder Dam was constructed, the design of grouting programs was considered to have became "systematic." However, in this case, remedial grouting entailing deepening the curtain and injecting very substantial volumes of grout subsequently was found to be necessary. There have since been many other cases in which the initial grouting was done "systematically" (using now outmoded concepts and procedures) and in which remedial grouting ultimately proved to be required.