Effect of Position and Inclination Angle of Cutoff Wall on Seepage Control in the Foundation of Dam Structure

Abstract

The present work presents finite element model which formulated to analyze the two- dimensional steady state seepage of water through the foundation of dam structure in the presence of inclined cutoff as seepage control device. A computer program using FORTRAN 90 language developed to determine the pressure head at nodal points, the exit gradients and the seepage discharge behind inclined cutoff walls. The results were presented by performing a parametric study for various design parameter. In this work the inclination angle()of cutoff changed (from =30 to =150), with inclined cutoff located upstream , mid distance, and downstream parts along the floor length of the dam structure respectively. The applicability of the model were examined with relevant existing approximations from literature, results demonstrate that installing cutoff in upstream part of dam structure with =60consistent with analytical solution(AE=5.11 %), while installing cutoff in mid distance of dam length agree well (AE=2.03%, for =105), the case of cutoff installed in the downstream part of dam structure strongly convenient(AE=0.2% for =30). The average value for coefficient of determination R2 for above the range of inclination angles which corresponding the various positions of cutoff wall was (0.9918,0.9713 and 0.9949) respectively, which indicates good agreement with previous studies and many of the factors studied.