Geo-Engineering Properties of Sedimented Flyash Bed Stabilized By Chemical Columns

Abstract

Ash ponds cover up enormous stretches of valuable land and accounts environmental problem. Adaptation of appropriate in-place stabilization technique may bring about enhancement in the geotechnical properties of the ash deposit as a whole, transforming it into a worthy construction site. In this present experimental program, large-scale laboratory model test tank of diameter 105 cm with 120 cm height has been filled with ash slurry at 70% water content with a centrally installed chemical column of sodium hydroxide (1% of NaOH by dry weight of the ash in the bed) having a diameter of 20cm. Undisturbed samples were collected from different radial distances of 15cm, 25cm, 35cm and 45 cm after curing periods of 7, 30, 60 and 90 days and the in-situ water content, dry density, unconfined compressive strength and hydraulic conductivity were measured. This method has been found more efficient in increasing the unconfined compressive strength and reducing hydraulic conductivity of the ash deposits in addition to altering other geotechnical parameters like in-situ water content and dry density. A substantial increment in strength was noticed up to a radial distance of 2D (where D is the diameter of the chemical column) from the center of the column.