ارزيابي آزمايشگاهي كاربرد يك نوع پوشش مصنوعي در زهكشيهاي زير زميني و مقايسه آن با پوشش معدني

Evaluation of Synthetic Envelope for Subsurface Drains and Its Comparison with Granular Envelope Under Laboratory Conditions

The purpose of this research was to investigate and compare the performance of a synthetic drainage envelope material with a granular envelope material vastly used in drainage projects of the region. This study was conducted in the soil and water research laboratory of Chamran University. Upward flow cylinder infiltrometers was used in these experiments. Granular envelope was designed according to USBR recommenedations ,and synthetic the envelope used was PP450. Drain outlet discharge variation, soil-envelope hydraulic conductivity under fixed hydraulic head and gradient ratio (GR) in the two envelopes were measured and compared. The results of GR test indicated that clogging potential was greater in the synthetic envelope. In regard to hydraulic conductivity, the performance of both envelopes was acceptable and could be used as drainage envelope material satisfactorily. Under all hydrylic heads used in these experiments, drain outlet discharge for the granular envelope was higher than synthetic envelope material.