Research on Bypass Seepage of Dam Abutment Deep-Thickness Sand Layer and Anti-Seepage Scheme

Based on a proposed earth dam, three-dimensional finite element analysis of bypass seepage of dam abutment deep-thickness sand layer was carried out to make cutoff wall extending length scheme, and the sand layer´s seepage stability is control condition of calculation. The finite element calculation results showed that: the influence of bypass seepage is limited along the direction of river stream, but the left bank around the dam toe is great. In which, with the increase of cutoff wall extending length, maximum seepage gradient of sand layer and seepage gradient of exit surface in the cross section of left bank near the dam toe are gradually decreased. The results also showed that: bypass seepage of dam abutment deep-thickness sand layer is mostly occurred in sand layer, moreover with the increase of cutoff wall extending length, bypass seepage quantity in sand layer and the whole left dam abutment are all gradually decreased, but its changing range is not significance.