Research On The Coal Wall Stability Influence In Larger Height Coal Seam By Water Injection

Anyuan coal mine large fully mechanized mining hard coal seam and coal wall exposed a large area, the implementation of coal seam water injection technology is easy to result coal wall spalling occur, how to ensure the implementation of stable conditions at the coal wall injection technology has become a major problem.Aiming at this problem,water infusion effect on the stability of large mining height.Propose a suitable large mining height coal injection technology.Firstly, analysis coal wall spalling failure modes of large mining height.Research on coal wall stability affect factors of mining height, the direction of promoting, supports and surrounding rock relationships. according to Anyuan Coal Seam geological data, analysis the weakening effect of water on the coal and working face rib spalling causes and easy spalling position though bar theory and Mises theory, for Choosing Seam Injection point to provide the theoretical basis.Then,test the moisture content, water absorption tests and physical and mechanical properties test of coal, analysis the relationship between coal and moisture content, failure criteria established under different moisture content of the coal, analyzes water bodies attenuation and infiltration in coal seam.Followed, analysis coal seam water injection anti spalling mechanism, research on seam infusion stress energy conversion and release into the role of coal wall stability.Set up a large fully mechanized mining face model by FLAC3 D software to simulate stress field and displacement field and plastic zone when coal in the condition of water injection or not, under different moisture content, different hole pattern, different injection pressure.Study the impact of water on the stability of coal in different situations.Finally, from the study, large fully mechanized mining face water injection should focus on softening the lower seam, coal moisture control in the 6% to 8%, injection pitch for 6m,injection pressure is 3 ~ 5MPa reasonable. According to the research results,4211 Anyuan coal injection mechanized mining face guidance. Practice has proved that after the water injection working face efficiency, lump coal improved, recovery improved, productivity improved, greatly reduce dust concentrations, and achieving the desired effects and significantly economic benefits.