بررسي تاثير خصوصيات سوراخ لوله هاي زهكشي زيرزميني و دانه بندي خاك بر ميزان گرفتگي لوله زهكش زيرزميني

Effect of Drain Perforation Characteristics and Soil Grain Size Distribution on Drain Line Sedimentation

Sediment accumulation is a major problem which sometimes leads to a complete failure of a drainage system. This problem is often encountered in noncohessive soils like silty and sandy soils. Soil particles stop flowing into the drain tube when a bridge is formed above the perforations. Therefore a relation between drain perforation and grain size distribution of the surrounding soil can be established to predict the amount of sediment entering through a perforation before a bridge is formed. Experiments were carried out using glass beads and different soil materials in a permeameter like apparatus. Results indicated that a circular perforation will allow a smaller amount of sediment accumulation before the bridge is formed. It was also found that corrected hydraulic radius of the perforation multiplied by a constant coefficient of perforation and DIG of the surrounding soil, was the best soil factor in this regard. Finally a relationship was derived for the prediction of drain line sedimentation using hydraulic radius of the perforation, and Dto of the soil.