Author(s)

Magdy M. Aboelela^*

Irrigation Engineering and Hydraulics Department, Faculty of Engineering, Alexandria University, Alexandria, Egypt.

In the present study, an analytical solution is presented to solve the problem of combined seepage, under a sheet piling cofferdam, applied to dewatering systems. Existence of the sheet pile creates a confined seepage followed by an unconfined seepage in the same field, which presents a combined seepage problem. Two equations were developed to analyze the combined seepage underneath a sheet piling wall. Using such equations, both the maximum height of the free surface just behind the sheet piling cofferdam (H_o) and the quantity of seepage discharge to be pumped out from the construction site (q) can be determined. The main parameters affecting the combined seepage characteristics underneath a sheet piling wall are: The depth of permeable foundation layer (T), the horizontal distance behind the sheet pile (X), the depth of excavation in the construction site (D), the embedded depth of sheet pile (S), the retained water head (H₁), the accumulated seepage water depth (H₂), and the side slope factor of excavation line (M). Study showed that, the above parameters have a great effect on the combined seepage, but with different extents.

Confined Seepage, Unconfined Seepage, Combined Seepage, Sheet Piling Cofferdam, Seepage Discharge, Phreatic Surface

Aboelela, M. (2016) Theory of Combined Seepage Applied to Dewatering Systems. Journal of Water Resource and Protection, 8, 743-755. doi: 10.4236/jwarp.2016.87060.