Abstract:
A method used by the Mangla Dam contractors for extending the trench around the core trench of the main dam is described. The idea was to reduce the seepage when the core trench was excavated. Bentonite obtained from Wyoming U.S.A. and passed through 200 mesh sieve was used. A mixture of 5% bentonite and 95% water by weight was prepared. This was allowed to flow into a trench 4ft wide. The excavation was carried out by Mani-towoc 4600dragline. The trench was excavated with Slurry always filling the excavated portion. Thy: level of bentonite solution was 3 to 5 ft above the watertable. The trench to a depth of 65 ft. was excavated and the sides of the trench never caved in. The bentonite mud plastered the walls of the trench without allowing any seepage of water. It is said that the bentonite mud is capable of supporting 85 ft. vertical walls. After excavating trench it was filled with materials having all grades varying from 3 inches to those retained on 200 mesh size. Detail specifications relating to gravel filled slurry trench are given. (Abstr. from Engng News, 1965, 10(1): 18).
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DOI:
DOI not available
Published:
Journal: Proceeding of West Pakistan Engineeringg Congress, Volume: 48, Issue: , Year: 1965