Study of slope stability of ash dyke raisings under static condition

There are more than 85 thermal power plants in India; of which majority are coal based producing approximately 100 million tons of coal ash yearly. With increased utilization of generated ash through usage in concrete, brick making and other embankment constructions, the utilization of the ash has increased considerably. However, the percentage of utilization is still insufficient and for most of the power plants ash is deposited in form of ash-pond in the vicinity of power plant as waste material covering several acres of valuable land. Moreover, for new power plants the land acquisition is a major issue and with limited area, rapid vertical expansions of Ash-dykes are inevitable. Present paper describes static analysis carried out on the ash-dyke sections with various raising stages. Based on the state of the art practice in the India, starter dyke section and subsequent raising geometry is selected. Using the in-situ test data performed on the existing ash-dykes, geotechnical properties of the deposited ash ponds are selected to perform the static analysis of the ash-dyke sections. A series of stability runs are carried out to map the factor of safeties at various stages of ash-dyke raising. Sensitivity analysis is carryout out to examine the influence of the geotechnical properties of the deposited ash in the ash-dyke. Present study helps the geotechnical professionals to choose better geometries of ash-dykes during planning stage to ensure sustainable performance.