Seepage Analysis of Core Section of Jhuj Dam

Abstract

Abstract: Zoned type Earthen dams are the type of Rolled fill Earthen dam because the soil is compacted by mechanical rollers in thin layers of 20-30 cm having central impervious core surrounded by shell as pervious material. These dams made since early days of civilization and constitute to be the most common type, because it is generally built of locally available soils proved to be most economical. The soil used in earthen dam are suspectable to seepage through the body of dam due to their permeability. Due to seepage soil gets reduces its strength and failures of dam may occurs. Past studies on earthen dam failures concluded that about 30% of dam failed due to seepage. An impervious central core is used in zoned type earthen dam to reduce the seepage quantity through the body of the dam and protects against the seepage failure of dam like piping and sloughing. Earthen dams are vulnerable to failures due to seepage that take place in the core since all soils are pervious to some extent. One of the best ways to control seepage problem in earthen dam is by using proper impervious soil for core section which provides the water tightness to flow through it. Thus, this paper analyses the usage of locally available soils with different combinations with central impervious vertical core and to study the seepage discharge by using Darcy law. The results obtained from the study is compared with actual seepage data obtained with existing soil in central core. Keywords: Impervious core, Permeability and Seepage, Smear effects, Phreatic line, Flow net