关键词: 点载荷, 煤岩颗粒, 断裂强度, Logistic模型

Abstract: The fracture strength of the feed of the graded crusher is an important factor affecting the particle size distribution of its products, which is related to the loading mode of crushing. In order to study the fracture strength of the feed of the graded crusher, a point load instrument similar to its loading mode is selected as the test equipment to carry out the point load test on the coal and rock particles with the size of 5 ~ 40mm, and the maximum crushing force and fracture stress of the sample are obtained, which can be used as the fracture strength evaluation index of coal and rock particles during graded crushing. The fracture strength of coal and rock particles in the same group has certain discreteness. Boltzmann model, Weibull model, Lognormal model and Logistic model are selected to fit them, and the model with the best fitting effect is selected to construct the fracture strength distribution model during graded crushing of coal and rock particles. The results show that under the action of point load, the fracture strength of coal and rock particles of the same group is very discrete; Among the four models, Logistic model is the most suitable to construct the fracture strength distribution model of graded crushing. The study of the fracture strength distribution model provides a theoretical basis for the prediction of particle size distribution of graded crushing products.