Evaluation of the Effect of Construction Procedure on Negative Skin Friction in Plastic Concrete Cut off Wall in Earth Dams

As a result of the construction procedure progresses in earth dams having cut-off, shear stresses on the cutoff wall increase due to the surrounding soil consolidation. This paper attempts to determine the effect of the soil consolidation in dam foundation on the negative skin friction (NSF) which develops on sides of the cut-off wall. For this purpose, some numerical analyses have been performed to consider the consolidation of the dam foundation soil, simulating the solid-fluid fully coupled phenomenon by the use of finite difference method (FDM) based on FLAC-2D). The interface element has been used to accommodate the possible slip, which occurs at the boundaries of the cut-off and the surrounding native soil due to the consolidation advancement. The computational results show that the construction progress of the dam body produces significant changes in the shear stresses on the cutoff wall sides as a result of the soil consolidation. Thus, an appropriate cutoff wall size should be employed such that the cut-off not only tolerate the NSF but also facilitates a safe situation at which it has reasonable function in the seepage control.

کلیدواژه ها:

Cut-off wall ، Negative skin friction ، Construction procedure ، Consolidation ، FLAC ، Fully coupled analysis