Research On Crushing Characteristics Of Limestone Under Stress Loading

In the engineering scenario,the composite crushing behavior of particles is very complex.At present,a unified theory is still lacking to give a reasonable explanation of the limestone material crushing laws and related characteristics.An explanation of the strength characteristics of limestone grains in combination with the current commonly used statistical distribution and the proposed corrugated distribution,an improvement of the generation method of the grain bonding model in the traditional discrete element method,an attempt to construct a rational grain bonding model to be able to reflect better the process situation of limestone material crushing,and an application to the study of the effects of different contact forms on the grain loading crushing are the main ideas of this paper.First of all,a series of experiments are designed to calibrate the physical parameters,mechanical parameters and contact parameters required in the discrete element simulation,and the particle accumulation experiment and the corresponding discrete element simulation are constructed to verify and calibrate.Secondly,the loading crushing test of single limestone particle is carried out,a new ripple distribution is proposed,which is compared with the widely used Weibull distribution to describe the particle strength effect,and the particle characteristic strength crushing probability relationship and particle characteristic strength particle size relationship are fitted respectively to verify the rationality of the ripple distribution.Based on the existing discrete element method,an improved particle model generation method based on element gravity is proposed.This method continuously adjusts the position of element particles through iteration,so that the element particles better fill the whole boundary and there is almost no overlap between the particles.A particle model with multiple regions and randomly distributed bonding bonds with different strength and spatial position is constructed.The model simulates the internal defects of limestone specimens to a certain extent and reflects the nonuniformity of internal mechanical properties of materials.Through the actual test and simulation,the crushing conditions of cube limestone specimens under different contact forms are compared and analyzed,and then the crushing law and related characteristics at the meso level are studied.The research on the crushing characteristics of limestone materials is helpful to the further research on the subsequent loading crushing theory of brittle materials and the optimization of Engineering mineral crushing production,which has good theoretical research significance and practical application value.