Abstract: The pick is the main load-bearing object of the mining machinery for cutting coal, and the prediction of the cutting force from the working face is very important to reduce the wear of the pick. The rock was considered as a particle matter for single pick cutting simulation by using the particle flow code (PFC2D). The influence of the contact state on the cutting force of the single pick was discussed by studying the characteristics of the interparticle force chain during cutting. The cutting force test was carried out on a single pick cutting rock test equipment, and the changing law of normal and tangential force with cutting parameters and the characteristics of falling fragments were obtained. The research results show that the relationship between the number of force chains and the length of the force chains for rock particles cut by a single pick is consistent with the uniaxial compression test results, and the cutting state of the single pick can be simulated by using discrete element method. The force chain network spreads and extends along the point contact direction, which is related to the cutting angle. The average normal force direction is "peanut"-like whereas the tangential force direction is "petal"-like. In addition, the number of force chains decreases with the decrease of cutting angle and the increase of cutting depth. The length of force chains increases with the increase of cutting distance. The maximum average length is about 8 particle sizes. The force chains tend to form at larger cutting angles. Furthermore, the normal force and tangential force of single pick cutting of natural sandstone decrease with the increase of cutting angle and the decrease of cutting depth. The linear correlation between the size of the cutting fragments and the cutting tangential force is 0.87. Compared with the Evans prediction model, the accuracy of normal force and tangential force based on force chain length is improved by 17.6% and 16.9% respectively. The research results lay a certain research foundation for the design of cutting pick, mining machinery cutting system and the optimization of cutting technology.

Key words: granular material, single pick cutting, force chain, force prediction