Research On Size Effect And Rate Effect Of Rockfill Particle Crushing Parameters

The non-uniform deformation of rockfill leads to the deformation or even crack of the impermeable body and the failure of impermeable function is the key technical problem of high earth rockfill dam at home and abroad.The fundamental cause of rockfill deformation is the breakage of rockfill particles in the dam body,which leads to the re-adjustment of the relationship between the forces and the spatial position of the particles.Previous studies have shown that indoor scale rockfill samples can not fully reflect the physical and mechanical properties of on-site materials in the dam body,and the crushing parameters of the two materials are not the same,that is,indoor scale rockfill has size effect.The rate effect of rockfill particle breakage parameters is studied to study the physical and mechanical properties of rockfill particles under seismic load.Therefore,it is of great significance to study the size effect and rate effect of rockfill particle crushing parameters.In this paper,the particle size of Yunnan red stone weir reservoir with 20-300 mm diameter was selected to carry out particle crushing test under the loading rate of 0.3-45mm/min.The size effect and rate effect of particle crushing parameters,such as particle crushing strength and elastic modulus,were discussed.The main contents are as follows:(1)The particle strength test of 20-300 mm diameter was carried out,the particle crushing criterion was studied,and the particle crushing strength was calculated.The elastic modulus of grain particles was calculated according to the uniaxial compression test method.The size effect of particle crushing parameters was analyzed.(2)The Weibull distribution function and Logistic distribution function were used to fit the experimental data of particle strength,and the size effect formula of particle strength under different loading strain rates was obtained.By fitting the relationship between the average elastic modulus and the average particle size,the size effect formula of the elastic modulus of particles under different loading strain rates was obtained.(3)The formula for the rate effect of particle crushing strength of different particle sizes was obtained by logarithmic treatment.The rate effect of particle elastic modulus is proved to be insignificant by analysis.(4)It is found that the particle size of the particle obeys the fractal distribution or normal distribution.The fractal dimension and the high-frequency distribution range of the particle after crushing are given.