Research On Shaft Uncovering Coal Outburst Prevention By Deep Hole Pre-splitting Blasting Grouting Technique

With the exploitation of coal resources into deep,the gas content in coal seam increased and the permeability decreased making the drainage more difficult. When encounter dangerous outburst seam in the deep wellbore construction process, to achieve the desired effect of Regional Gas Control requires six to eight months if using only drilling drainage, but there is still much to dangerous at the time of uncovering coal, seriously hampered the coal mining alternately.In this paper, we analysis the insufficient of traditional Coal Uncovering, from the theoretical analysis and model tests start, combined the current research and practical issues in expose coal site,put forward the method of pre-splitting curing to prevention and control of gas outburst,has a great significance in shorten uncovering coal period and speed up the shaft construction.This article through the analysis of coal and gas outburst mechanism and prominent factors in the process of shaft uncovering coal,from gas and mechanical strength of coal, based on the deep hole pre-splitting blasting theory and the theory of similar simulation, carries on the deep hole pre-splitting blasting grouting outburst prevention technique of laboratory simulation test,also use the numerical analysis software ANSYS to simulation fractures development in coal and rock after blasting.Results show that after blasting the interconnected macro fracture network can be formed in coal and rock through the effect of control holes,Grouting materials can penetrate through the cracks between the blast holes and control holes form the coal into a solid block and combined with the solid roof,making a high strength anti projecting retaining wall. Combination of huainan mine shaft uncovering coal experiments,achieved a good results, the experimental data show that within the scope of 3 m the gas concentration increased 1.8×2.5 times and extraction from scalar improved 1.5-4.1 times, grouting,8 grouting hole have consumpted of cement 3.5 t in total, sodium silicate 220 kg,that is 1.8 times higher than the theoretical calculation. Instructions after blasting experiment,formed a three-dimensional unicom type fracture network in the course of coal seam, making a lot of gas pressure relief for extraction, and greatly improve the seam grouting amount, make soft coal cohere curing, eliminate highlight the danger to ensure the safety of coal mine production and provide new ideas for wellbore and shimen fast uncovering coal.