Chemical Grouting Summary, Steel Outlet Works Liner – Shadow Mountain Dam, Grand Lake, Colorado

This article documents the work performed by Bureau of Reclamation personnel and employees of the Northern Water Conservancy District on the steel outlet works liner on Shadow Mountain Dam, Grand Lake, Colorado. During a facilities inspection, cavitation damage and drummy voids were found behind the 36- by 48-inch-long stainless steel liner located in the gate shaft on the river outlet works. This was reported to have been grouted with cementitious grout in the late 1980s. A subsequent inspection for repair possibilities in March 2005 was performed by the Loveland Area Office and the Technical Service Center, Materials Engineering and Research Laboratory, (MERL). Epoxy bonded epoxy mortar repair of the damaged concrete areas and chemical grouting were determined to be viable means of repair for the cavitation damaged areas on the downstream edge and behind the steel liner. During the first week in September 2005, members of the Northern Water Conservancy Districts maintenance team removed a portion of the 5-inch vent tube and installed an inflatable rubber packer to isolate the vent from chemical grout intrusion. They performed epoxy bonded epoxy mortar repairs on the downstream cavitation damaged areas on the crown and sides of the liner. They also installed access ladders and supplied a pump to assist in removing water flowing from behind the bulk heads into the work areas. On September 8, 2005, MERL began chemical grouting operations on the 36-inch-square steel liner.