Influence of Geosynthetic Encased Stone Columns over Coal Ash Bed

Abstract

Electricity generation in the INDIA is and would remain mostly by coal centered stations in the nearby future.Having a look at the current scenario it can be comprehended that almost 170 million tons of coal ash is generated in India every year. Fly ash nowadays are being used by various sectors such as cement production, brick manufacturing etc. but consumption of fly ash is not likely to surpass 20 to 25% and therefore numerous thermal power plants in our country has no other possibility but to construct ash ponds. Such ash ponds conquer large land area which is otherwise useful for agricultural purpose. The area gets occupied to a height of 15 to 20m in a period of 5 to 10 years. Past this period the power plant has to either rise the height of the pond (which may threaten the safety)or construct a new facility conquering more of cultivable land. The much area employed by fly ash remains unutilized as the forsaken ash is mostly in slurry from possessing very low shear strength. Stone column is a ground improvement technique which is used to enhance the bearing capacity of soft soils. Though, a lot of study has been done upon provision of stone column and encased stone column over soft soil deposits, the influence of stone columns and encased stone columns over coal ash bed is yet to be studied. In this study effort has been made to obtain the effect of stone columns and geosynthetic encased stone columns over coal ash deposits. As there are various types of geosynthetics are available, 3 different kinds of geosynthetics are used to obtain the behavior of geosynthetics upon the performance of those columns. Again diameter and aggregates used in the stone column also play a vital role in the enactments of those columns. So columns of different diameters filled with different aggregates are also studied. Further from the literature studies it was observed that partial encasements also have an important role in the characteristic behavior of stone columns and hence it is also taken care of by using 3 different encasement lengths.