Engineering geological assessment of the proposed Kakasharaf Dam, Lorestan, Iran

This paper describes the results of the engineering geological investigations and rock mechanics studies carried out at the proposed Kakasharaf Dam site. Analyses were carried out in terms of rock mass classifications for diversion tunnel, permeability of the dam foundation and determination of rock mass strength parameters. In this study, the Kakasharaf dam site, constructed on the Kakasharaf River to the south east of Khorramabad in Lorestan province, south western Iran, was investigated from the stand point of the aforementioned engineering geological aspects. The proposed Kakasharaf Dam site is located on sedimentary rock of the upper Cretaceous age and on Quaternary deposits. Sedimentary rocks consist of Buff-grey limestone, marl limestone and shale limestone. Studies were carried out both at the field and the laboratory. Field studies include engineering geological mapping, intensive discontinuity surveying, core drilling, pressurized water tests and sampling for laboratory testing. Uniaxial and tensile strength tests were performed and deformation parameters, unit weight and porosity were determined on the intact rock specimens in the laboratory. Rock mass strength and modulus of elasticity of rock mass are determined using Hoek-Brown empirical strength criterion. Engineering geological investigations, test result and computations indicated that there will be no foundation stability problems. Detailed geotechnical investigations are required for the final design of the dam