Considering The Size Effect Of Particle Strength Test Research

Deformation controlling is the core of rockfill dam design,which has not been a good solution.The deformation of the rockfill is mainly caused by the filling,slip and particle structure changes caused by the crushing of the rockfill particles.Therefore,the particle strength is the key mechanical parameters and needs to be resolved first in the rockfill deformation of the mesoscopic simulation.Rockfill particles are the smallest units of rockfill loading,and their strength has a significant size effect.That is,different sizes of rock particles,the strength and deformation characteristics of the existence of mechanical differences.The reason is that rock particles containing initial defects such as joints,cracks,microcracks are nonuniformity.In this paper,the strength distribution of rockfill particles is studied by the crushing strength test of a large number of rockfill particles,and the strength distribution rules are given and the parameters are determined.Conducted a dry and saturated rock pellet crushing test,the test material selected from the Gushui hydropower project blasting basalt,grouping into(20-22),(22-24),(24-26),(26-28)(28-30),(30-32),(32-34),(34-36)(36-38),(38-40),each group of particles at least 32 samples of the uniaxial crushing test,we get the particle crushing strength.The intensity distribution of the strength of the rockfill was obtained by using the three-parameter Weibull model and the improved logarithmic normal distribution,and the intensity distribution parameters(m,0d,0?)were obtained.The fitting effect of the two distributions is compared,and it is found that the improved logarithmic normal distribution is better than the Weibull distribution.Based on the Weibull strength size effect formula proposed by Ma Gang,the formula of strength scale of rock particles with different sizes from the same parent rock is deduced based on the improved logarithmic normal distribution.