Design and construction considerations in filling a void under the Webber Dam spillway

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:220207

Dumont, M F; Baltz, J ^[1]

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1. Acres International Corp., Amherst, NY (United States)

This paper describes design and construction considerations in filling a large void below a concrete spillway structure on a sand foundation. The selection of the fill material, the mix design, the detailed method of placement under water, monitoring and testing procedures, and post-construction pressure grouting are presented. A brief description of finite element modeling of the structure/foundation interface is also presented. The Webber Dam Hydroelectric Project, which is owned and operated by Consumers Power Company, is located on the Grand River near Portland, Michigan. The major project structures include a powerhouse and concrete spillway structure 32-ft (10 m) high between earth embankments. During the installation of piezometers at the site in November 1993, as part of an ongoing reconstruction of the concrete spillway, a large void was detected under the concrete spillway slab. Probing through the existing pressure relief holes indicated a void approximately 60-ft (18.3 m) by 80-ft (24.4 m) by up to 7-ft (2.1 m) deep. It is suspected that the void was formed when high flows over the spillway caused suction at the pressure relief holes in the spillway base slab, resulting in erosion of the sand foundation. The void was successfully filled with 158 cu yd (121 cu m) of controlled low strength material (CLSM) in March 1994. The interface between the fill material and the foundation sand was subsequently pressure grouted with cement grout.

• OSTI ID: 220207
• Report Number(s): CONF-9507190--
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
DAMS
FILLERS
FINITE ELEMENT METHOD
FOUNDATIONS
GRAND RIVER
REPAIR
SPILLWAYS
STRESS ANALYSIS
VOIDS