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Title: Development of design criteria and acceptance specifications for plastic filter cloths
Authors: United States. Army. Corps of Engineers. Lower Mississippi Valley Division
Calhoun, Charles C., 1946-
Keywords: Filter materials
Plastic filter cloths
Design criteria
Publisher: U.S. Army Engineer Waterways Experiment Station.
Engineer Research and Development Center (U.S.)
Description: Technical Report
Abstract: Laboratory and field investigations were conducted to obtain data for the development of design criteria and acceptance specifications for plastic filter cloths used as a replacement for granular filter material. The investigations included a survey of CE Districts and Divisions to determine current uses and experiences with filter cloths. Information was also obtained from various other agencies on the performance of filter cloths. Based on the results of the survey, seven filter cloths were subjected to laboratory and field tests. Performance information was obtained on two other cloths not tested during this study. The chemical compositions of the cloths were determined. Tests were conducted to determine such physical properties of the cloths as size of opening, percent open area, strength, abrasion resistance, and resistance to deterioration from the elements. In addition, field exposure tests were conducted. Filtration tests were conducted using various soil types. The tendency of the cloths to clog due to the migration of fines was studied using special filtration tests. Head losses through the cloths were determined from flume tests. Field tests were conducted in which stones were dropped on the cloths from various heights. Field performance data were obtained from visits to several sites where filter cloths had been used. Results of the study indicated that cloths made of 85 percent or more by weight propylene, vinylidene chloride, or ethylene and that meet various tests given in the report do not tend to deteriorate under most conditions. Recommendations are made for strength and abrasion resistance requirements for cloths used for various purposes. Laboratory tests indicated that cloths should be woven and have distinct, visible openings to prevent clogging. The filtering properties of the cloths are related to the opening sizes (termed "equivalent opening size" or "EOS") and percent open area. Filter criteria in terms of EOS and percent open area are presented for various soil types. Field performance data indicate that in instances where the revetment is relatively light and where relatively high seepage velocities or rapid fluctuations in the differential hydrostatic pressures can occur, the open area of the cloth should be as large as possible with in the limits set forth in the report. Information from questionnaires on uses of filter cloths in the Corps of Engineers is summarized in Appendix A. NOTE: This file is large. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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