Laboratory Investigation on Seepage Control Measures through Alluvial Foundations

Seepage under coastal structures including coastal dikes is one of the major issues for controlling stalinization of coastal lands and stability of the related structures. So far, for analysis of seepage under hydraulic structures much research works have been conducted in the form of numerical models. However, less field and laboratory works have been done for evaluating of the numerical models. In the present research, a laboratory model was made to simulate seepage and its controlling measures under coastal dikes. The model consists of a flume 8m long, 1m deep and 1m wide, in which horizontal blanket and vertical cut off were provided by Perspex sheets. The flume was made of steel frame and Perspex as well as thick glass sheets. The foundation material was made of clean fine sand, compacted to a uniform density and covered the bottom 50cm of flume. Perspex sheets were employed as blanket and cut off variable length. The piezometric heads at the downstream side of dike were measured using small diameter clear plastic tubes. The results of the test showed that the optimum ratio of blanket length and cut off depth to the depth of water and the thickness of foundation at the upstream side of dike for minimum seepage loss and control of piping was 8 and 0.8 respectively.