عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Regarding the role and importance of subsurface drainage in water table control, many studies have been made throughout the world to find out new techniques and more economical solutions, especially as related to different pipe envelope material and their installations. This research was conducted to investigate the use of rice husk, as drain envelope material, in drainage installations. In addition, it was also compared with the standard gravel envelope material. Therefore, some such physical and hydraulic properties of rice husk as bulk density, void ratio, gradation curve and hydraulic conductivity were needed to be assessed. Also, a 2-side wall physical model that simulated a part of drain trench (enabling water table control) was used to simulate land drainage in the laboratory and as well to test for the filtration and water conductivity of rice husk envelope. This experiment was carried out in two soils which definitely require envelope material as base on standard methods. The results in this study showed that the hydraulic conductivity of rice husk even in its compact form is more than necessary to guarantee the hydraulic function of rice husk envelope. Also, rice husk envelopes have possess the appropriate filtering function as compared to mineral envelope. Discharge rate of drain through rice husk envelope is however, lower than that in gravel envelope, but because of more cost involved in mineral envelope, the use of rice husk as envelope is reasonable and recommended.