A new measure,called hydraulic slotting,was described and studied in detail,and the mechanism of hydraulic slotting was put forward and analyzed.

The paper researchs the principle of protective seam mining,hydraulic slotting method and executing-digging technology to avoid risk of coal-gas outburst,and its practices in coal mine.

Analysis on the security of hydraulic cutting measures for outburst prevention

Grave protrusion coal seam tunnelling hydraulic cutting protrusion-dispelling measures is a new technology in the world.

The results show that mighty compound cutting can give a good effect of sinking and blasting in hard rock shaft,and sinking velocity adopted for 2.

Combining the specific engineering practice,this paper discussed the theoretic and practical bases of reasonable lying of the cuttings hole toward characteristics of the big cross-section sap tunneling demolition,and calculated the reference quantity of explosive in single hole under condition of the mild-rigidity rocks.

By using the LS-DYNA 3D nonlinear dynamic finite element software,the elasticity calculation model was established to analyze the generation and transmission of stress under explosive charge in 4 typical cutting patterns,those used in shaft excavation by one-step blasting were optimized and compared by numerical simulation to select the optimizing cutting patterns.

In this paper, the author combined the experience of tunnelling construction bystraight-in hole cutting blasting within 30 years in the country with the theory and practice in the blasting wor of Sweden, U.