Effect of Presence of Single Cavity Upstream Side of Sheet Pile Wall on Steady Time and Quantity of Seepage

When the sheet pile is used as the reservoir wall or retains the action of saturated fills and cuts for construction works, it will be certain that the seepage occurs from the back side (retained side) to the working place (opposite side). Often, the rate of seepage and its quantity in homogenous strata depends mainly on the permeability of soil. However, the presence of cavity certainly has a direct impact on trend, steady time, and the quantity of seepage. The present study considered a preliminary attempt to measure this impact through physical model. Eighteen model tests are conducted to study the effect of different locations and diameters (size) of single cavity on the seepage problem when it is presented at upstream side (back side) of the sheet pile wall. Period of completion every model test ranged from four to seven days. The start time of seepage when the water began to flow from the downstream side (working place) ranged between 13min and 26min, which depended on the location of cavity and its size. However, the results show that the quantities of seepage generally increase with the smallest size of a cavity and with the farthest horizontal distance from the sheet pile. The maximum quantity has been recorded when the cavity is located at the same level of sheet pile end.