Research On Technology And Assembly Drill Tools In Soft Outbursting Coalbed For Drilling Gas Drainage Bore

It is very difficult to drill in soft coalbeds because of soft coal quality and high gas contents, which holespouting and holecaving are followed frequently to result in low rates of pore-forming and low bore-depth . it impacts effectiveness of gas drainage , gas drainage in soft coalbeds is a difficult problem in the world, So it is very important to research the technology and assembly drill tools in soft outbursting coalbed for drilling gas drainage bore.The technology of auger drilling is a usefull method to drill the bore of gas drainage, because of low disturbed holewall and high rates of pore-forming. In this paper, the model of auger rods used in auger drilling are established based on mechanics of removal of cuttings, whose dynamic parameters and structural parameters are optimized with mathematic optimization and the correct of mathematic optimization is proved with the experiment. Then drill bits mated with auger rods are designed and analysed in strength with ANSYS software, which can find damage area on fins of drill bits.Then the drilling technology of auger drilling and the accidents of drlling are also researched. At last, the third coal mine of Yangquan achieve a good effectiveness with this technology and drilling equipments designed in this paper in soft coalbeds.According to the research, drilling technology and drilling tools suitability to drilling in soft coalbeds are put forward to improve the rates of pore-forming and the effectiveness of gas drainage, which supply reliable safe guarantee to the coalmines.