EFFECT OF MEDIUM TO FINE SAND ON COMPRESSION INDEX OF CLAYS

Abstract

A lot of study has been done on compression index, but no specific study on compression index has been made to obse-rve the effect of presence of sand in fine grained soils. Importance of studying this lies in the fact that most of the soils in nature are not pure clays, but are mixtures of clays, silts, sands and possibly even gravels. Earlier studies done on compression index provides correlations for estimating compression index without performing conventional consolida-tion test. However, these correlation do not take into accou-nt adequate factors affecting compression index or reliability of them is in question due to limited experimental support. In the present study about thirty conventional conso-lidation tests were conducted on sand—clay mixtures. Two different types of clays of medium and high compressibility have been selected for the work. The percentage of sand was varied as 0%, 10%, 206, 30%, 40% and 50%. The change in the. value of compression index of soil due to presence of sand in clays has been obtained. Other properties like liquid limits, plastic limits, specific gravities of the sand—clay mixtures were also. determined. Analysis and discussion of test results reveals the degree of reliability of