Abstract:

Particle breakage of coarse granular aggregates modifies its structure directly, influencing its dilatancy, friction angle, strength and permeability. In order to accurately describe stress-strain relationship of coarse granular aggregates, especially in high pressure with significant particle breakage, it is indispensable to develop coarse granular aggregates constitutive model incorporating particle breakage. According to triaxial test results, the stress-strain relationship incorporating particle breakage is developed, on which a constitutive model is generated incorporating particle breakage with application of associated flow rules. The constitutive model incorporates the influences exerting on dilatancy and friction angle by particle breakage. The parameters of model are determined by mutation particle swarm optimization algorithm, on which the stress-strain curves of triaxial test are simulated. The simulation of model presentation and test results accurately describe dilation and contraction, strain hardening and post-peak strain softening features of the coarse aggregates at various confining pressures.

Key words: particle breakage, breakage energy, stress-softening, mutation particle swarm optimization algorithm, friction coefficient, critical state line, dilatancy