Effect of Randomly reinforced Soil on Increasing Resistance Against Piping Phenomenon

Piping is a phenomenon that commonly occurs at downstream of hydraulic structures such as earth dams, irrigation channels and drainage network under the influence of upward seepage. Piping is considered as the main mechanism of hydraulic structures failing. In this work an experimental program was set for determination the seepage velocity and piping resistance for unreinforced and reinforced sand silty samples. Two type of fibers (Polyester and Polyethylene terephthalate) with different diameter (0.2mm and 0.3 mm) was used for preparing reinforced samples. The experimental tests was conducted on samples without and with different fiber content (0.5%, 0.75%, 1% and 1.25%) and fiber length (5, 25, 35 and 50 mm) under different hydraulic heeds in a special designed apparatus. Discharge and seepage velocity of water flow through unreinforced and reinforced samples was measured and calculated and Comparison was made. The results showed that the inclusion of fiber reduces the seepage velocity and increased the hydraulic gradient and piping resistance. Furthermore, increasing of hydraulic gradient and piping resistance is function of fiber content and fiber length.