A METHOD FOR FINDING MINIMUM VOID RATIO OF SAND

Abstract

Vibration provides the most effective means of compact-in.g cohesionless soil. The type and intensity of vibration and state of stress to which sand sample be subjected are important for study of sand compaction under vibrations.. Various investigators have used vibrations for obtaining maximum density for minimum voids of sand. But no standard method could yet be suggested.. The present study is planned in the light of suggesting a procedure for obtaining minimum void ratios. Tests were performed on four types of air dry sand. Three different moulds were used. Horizontal steady state vibration table was used for imparting vibrations. Four types of sand were compacted on horizontal vibration tables in three different ,moulds (Proctor's mould, C.B.R. mould, and one specially fabricated mould cm dia and 28 cm high) at different frequencies and accelerations, The significant conclusions of the study are 1. Time of vibration required to cause maximum compaction increases with increasing size of mould.' 2. Higher acceleration is required for maximum possible compaction in a smaller mould. 3. Final relative density obtained for various sands under similar vibration conditions is of the same order, but the void ratios are quite different. xi Thus the relative density parameter can be taken for study of compaction characteristics of various sands.. 4. Maximum density for finding minimum void ratio can be found by performing a series of tests from frequency 10 to 20 cps with acceleration 0.75 g to 1.50 g, slowly pouring sand during vibration into a C.B.R. mould for a sufficient time of 2 to 3 minutes.