Mohammad Sedghi-Asl - Assistant Professor, Soil Science Department, Faculty of Agriculture, Yasouj University, Yasouj, Iran
Mansour Parvizi - Assistant Professor, Civil Engineering Deparement, Faculty of Engineering, Yasouj University, Yasouj, Iran
Mohsen Armin - Assistant Professor, Watershed Management Department, Faculty of Natural Resources, Yasouj University, Yasouj, Iran
R Flores-Berrones - Research Engineer, Mexican Institute of Water Technology, Paseo Cuauhnahuac ۸۵۳۲, Jiutepec, Mor. ۶۲۵۵۰, Mexico

In this paper we investigate the mechanism of internal erosion caused in the right abutment of the Shahghasem dam’s spillway. Shahghasem dam is an earthen dam located in Yasouj, in southwest of Iran. A significant hole and pipe have been observed in the corner of the right abutment from upstream view. The foundation is Marlstone, which has low cohesion and susceptible for internal erosion and piping in some conditions. Going through details of the design maps has shown that Lane’s criteria for selecting safe dimensions of the seepage control measures have not been considered properly. A series of the supportive walls are designed to attach to the right part of the spillway in order to increase the length of seepage. The pipe route of the erosion should also be grouted with high quality concrete.

internal erosion, Marlstone, piping, spillway, Shahghasem dam