A Review on Various Geotechnical and Geophysical Investigations for a Dam Rehabilitation Project

A dam is a massive hydraulic structure, built across a river to create a reservoir at its upstream for various purposes such as hydropower generation, irrigation, flood control, domestic and municipal supplies, and so on. They are major engineering structures that are designed and constructed with long-life expectancy. In India, most of the large dams are older than 25 years and require proper maintenance. To ensure efficient and safe operation of the dam, rehabilitation of dam is done. Before conducting rehabilitation activities, a detailed investigation of the dam body including surrounding soil is carried out. For embankment dams, appropriate borrow areas are identified, and disturbed and undisturbed samples are extracted. Various laboratories, as well as field tests, are performed on the extracted specimen. For concrete/masonry dams, representative cores are extracted from an existing dam. Various destructive and nondestructive tests are performed on the extracted core for assessing the existing condition of the concrete/masonry dam. For in-depth exploration, various geophysical methods are used to detect hidden defects in the dam bodies and also in surrounding soil too. Ground-penetrating radar (GPR) method is the most suitable technique for detecting cracks in a dam body and also to identifying leakage zones. The main objective of this paper is to review various geotechnical and geophysical investigations carried out for a dam rehabilitation project. In this paper, numerous articles have been reviewed to discuss the various prerequisites for a dam rehabilitation project.