STABILITY ANALYSIS OF FLY ASH-BOTTOM ASH MIX EMBANKMENT

Abstract

Coal-fired thermal power stations are India's primary source of electricity generation. The majority of electricity is generated by coal-fired thermal power plants, which account for 51.1% of total electricity generation (Ministry of Power). Today's coal-based thermal power industries are growing at a rapid pace due to the need for higher electricity production. In comparison to imported coal, which has a low ash level of 10-15%, the coal available in India is low-grade coal with an ash content of 30-45%. This leads to the generation of ash in high volumes causing disposal and environmental problems. In most cases, these plants create two forms of ash: fly ash and bottom ash. In the present study, a complete experimental analysis of the strength and other geotechnical parameters of different mixes of fly ash and bottom ash was carried out. The study's major goal was to analyse the engineering behaviour of fly ash-bottom ash mixes obtained from NTPC Dadri Plant and their feasibility for use as an embankment material. Fly ash (FA) and bottom ash (BA) were mixed in different percentages such as FA:BA=100:0, FA:BA=75:25 (i.e., FA=75% and Bottom ash=25%), FA:BA=50:50, FA:BA=25:75 and FA:BA=0:100 by dry weight. The geotechnical properties of different fly ash-bottom ash mixes were determined in the laboratory by conducting several experiments such as particle size distribution, specific gravity, light weight compaction test, Core Cutter Test, and Direct shear test. The test results data obtained from the above tests were used in the analysis of the embankment in GeoStudio SLOPE/W 2018 software which is based on the limit equilibrium method. The embankments made of different mixes of fly ash and bottom ash were analysed under the effect of their self-weight, surcharge loading, presence of water table and pseudo-static loading, and their variation in Factor of Safety (FOS) was determined.