Engineering Geological and Geotechnical Assessment of the Foundation of Yaragol Gravity Dam — A Case Study form India.

Engineering geological and geotechnical assessment of the dam foundation are essential for the design of the dam to ensure safety. At the southeastern part of Karnataka, Yaragol gravity dam is being constructed, which is designed based on site geomorphological and geological conditions and economic reasons. This paper discusses the results of the engineering geological and geotechnical investigations that have been carried out at the foundation levels of the dam. The dam foundation is composed of foliated gneiss and granite gneiss belonging to Archean to Paleoproterozoic age with intrusive dykes. This study is based on field and laboratory investigations, surface discontinuity mapping, drilled borehole data and in-situ shear testing. In-situ shear parameters of rock-rock interfaces and concrete-rock interfaces were conducted for the evaluation of dam stability against sliding. The classification and rock mass quality of the dam site is assigned using the rock mass rating (RMR) for all the 19 blocks and allowable bearing pressure (q_allow) is assessed based on rock types and RMR. At all the blocks foundation, geological defects were mapped and analyzed and treated with suitable engineering measures. Based on structural features mapped, curtain grouting and consolidation grouting is recommended. [ABSTRACT FROM AUTHOR]