ONE-DIMENSIONAL COMPRESSION BEHAVIOUR OF' UNIFORMLY GRADED SAND RELATED TO SINGLE PARTICLE CRUSHlNG STRENGTH

YUKIO NAKATA , YOSHlNORI KATO , MASAYUKI HYODO, ADRIAN F. L. HYDE and HIDEKAZU MURATA

 ABSTRACT In order to compare one-dimensional compression behaviour with the crushing strength characteristics of single particles, one-dimensional compression and single particle crushing tests were carried out on various granular materials with uniform gradings. The average characteristic tensile stress acting on a particle in a sample was calculated using a simplified approach. The one-dimensional compression yield stress was related to the particle size and this was also related to the single particle crushing strength. The decrease of the vertical yield stress with increasing initial void ratio can be explained by the increase in the particle characteristic stress as the void ratio increased and a corresponding decrease in co-ordination number. The single particle strengths were compared with the characteristic tensile stress for a particle embedded in the soil matrix. The logarithm of the characteristic tensile stress at maximum compression index for a particle embedded in a granular matrix could be related to the logarithm of the single particle strength multi- plied by a proportional factor. The introduction of a factor was necessary because the calculated average characteristic tensile stress did not take into account the non-uniform distribution of inter-particle stresses. The ratio of the single particle strengths to the average characteristic tensile stress for a particle embedded in the soil matrix was considered to be an indicator of the non-uniform distribution. This ratio decreased and hence uniformity of inter-particle stress distribution increased with angularity and surface roughness.

Key words: compression, (microscopic stress), particle crushing, sand, (single particle crushing strength), yield (IGC: D5)