Evaluation of landslide analyzing models in weak rocks—case study: Abnahr damsite, Kohgilouyeh and Booyer Ahamd Province, Iran

Abstract

The right abutment of Abnahr dam consists of Cretaceous marl and some marly limestone that are highly fractured due to tectonic stresses. Low strength and highly fractured structure of the rocks result in fragmentation during drilling by the rock sampling tools. However, this material is still too strong for conventional soil sampling methods. The types of marl are similar to rock material in natural landscapes but drilled material has soil-like behavior. This paper evaluates the behavior of this material in slope stability problems that concern the right abutment of Abnahr dam in existing conditions. For attaining reliable answers to this problem, several undisturbed samples were provided with assistance of the experienced experts and using specific methods. As these samples were rather soils, they were tested by various soil tests such as three-dimensional tests. Moreover some samples were gathered by hand-operated methods including test pits. In order to gain information about the rock parameters, several rock tests were performed. In the next stage, by use of the results of laboratory tests and field observations, slope stability analyses were performed on several models of right abutment of the dam. Lastly, a comparison between different analysis methods of the performed models on right abutment under virtual loads led to important conclusions.