Evaluation of sieve and permeameter analyses methods for subsurface drain envelope laboratory research in Pakistan

Abstract

Properly designed gravel envelopes for subsurface horizontal drain pipes did not give satisfactory results in the Fourth Drainage Project (FDP), Faisalabad, Pakistan. Poor handling and placing of the granular envelopes were considered the main reasons for failure. This study investigates whether the failure was also because of the existing selection procedures for gravel envelopes or not. USBR design criteria (sieve analysis) were used for distinguishing between the good and poor envelopes. Permeameter experiments for selecting the envelopes for subsurface drain pipes based on these permeameter test results have now been started at SCARP Monitoring Organisation (SMO) in collaboration with the Netherlands Research Assistance Project (NRAP), International Waterlogging and Salinity Research Institute (IWASRI), Lahore. A one-dimensional upward flow permeameter with four rectangular perforated drain plates was used for testing the subsurface drain envelopes. Another hypothesis for this study was to verify the methodology adopted in permeameter experiments. The effects of sieve and permeameter analyses methods on selection of subsurface drain envelope selection is reported. Following is a recommendation for comparing the permeameter test results obtained in Pakistan with those obtained in Belgium and Canada for worldwide use. This paper also accomplishes the objective of distinguishing between good and poor drain envelopes in a more simple way.