Development And Application Of Anti-sloughing Drilling Device In Three-Soft Coal Seam

The primary method to deal with mine gas is extracting gas by boring holes. Because of the physical and mechanical properties of coal seam, accidents such as hole collapse, sticking of tool, burying drilling, wedging of drilling rod,pitch contraction occurs a lot during working on the "three soft" coal seam, It hinders the process of boring holes and safety of coal mining.After the research on the mechanism of fracture of coal rock, the form and process of fracture by cutting the rock are clarified. Analytic method is used in the analysis of the stress state of drill,and analytical dynamic model is established.It provides theory reference to the study of abrasion mechanism and optimization of drill. Analysis of the three soft seam drilling failure mechanism, based on the physical and mechanical parameters of liujialiang coal mine, using FLAC3D finite element simulation software application for drilling rock stress-strain process simulation, a new anti-collapse device applied to the extraction of mine gas is developed. After the drill structure has been simulated by finite difference software FLAC3D, the parameters of drill structure are optimized scientifically.The effectiveness of this device has been tested by drilling in the 5133 working face of LiuJialiang area in XuanGang mining area.