Laboratory Investigation of Filters for Enid and Grenada Dams
Abstract
Before final selection of the filters for Enid and Grenada Dams was made, laboratory tests were performed to check the stability of all filters which had been proposed for use. Tests were also made of a locally available sandy gravel to determine if it could be satisfactorily used for the gravel blanket beneath the dumped riprap on the upstream slopes. On the basis of the laboratory tests, three filters, C, D, and,S were selected for use in the design of the drainage facilities for these dams. Gravel D would be used for draining silty sands and all finer grained soils; gravel s, as a filter to drain sands and as a filter for the relief wells along the toe of the dams; and gravel C, as a filter to drain gravels D or S and as a water-carrying layer of gravel. Tests on the locally available sandy gravel indicated that a satisfactory gravel blanket beneath the riprap at these dams could be developed by using all the sand and gravel coarser than a No. 28 Tyler sieve, placing this as a 12- or 15-in. layer, and harrowing until the bottom 3 in. consists of particles 25 per cent of which are finer than 2 mm and the top 3 in. consists of gravel 30 per cent of which is larger than 1 in.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1948
- Accession Number
- ADA637578