Friction Angles of Sands – An Appraisal

Abstract

River sand is a naturally occurring conventional construction material, which has good frictional properties. Due to a steep rise in the construction activities all over the world, natural sand resources are getting depleted. This has favored / forced the construction industry in general and geotechnical engineering practice in particular to go for M-sands. This necessitates a proper understanding of the frictional characteristics of M – sands. In this technical note, the results from a comparative study of the friction angles of river sand and M-sand with reference to the effect of grain size, grain angularity, dry density and gradation are reported. It is shown that M-sand exhibits higher friction angles than river sand at minimum density levels and river sand exhibits higher friction angles than M-sand at maximum density levels, on average, irrespective of grain size. It is also shown that poorly graded M-sands exhibit higher friction angles than well graded M-sands at minimum density levels, whereas well graded river sands have higher friction angles than poorly graded river sands irrespective of density levels.