Effect of Relative Compaction and Percent Fines on the Permeability of Soil

Abstract

Permeability is the major property of soil affecting various engineering aspects. It is one of the indispensable soil properties which are to be taken utmost care of in soil problems like settlement of foundations, seepage through and below the earth structures like dams, yields of wells, constructions of highway roads, etc. The aim of this research is to reduce the permeability of soil sample by varying the percentage of percent fines and fly ash and then compacted so that the voids present in soils are filled up and the settlement of the structures is reduced. This paper also addresses the effect of percent fines and fly ash on the permeability of the soil. Soil is altered with inclusion of fine content and fly ash in 30, 40, 50 60 and 70% to form different soil mixes. Tests were carried out to determine the index properties, compaction characteristics with changing the height of fall and weight of hammer and permeability of remolded soil. The maximum dry density (MDD) and optimum moisture content (OMC) decreased and increased, respectively with increase in percent fines content and fly ash. It is seen that up to 40% fines soil proves to be a better material as percent fines while above 40% fly ash serves as a better percent fines material and reduces permeability to a much greater extent than soil. Thus, with the decrease in permeability by the effect of compaction and percent fines the shrinkage risk of the soil is also decreased. Thus, the settlement of the structure is decreased.
Keywords: permeability, fly ash, percent fines, Proctor test, settlement