Deformation and Damage Law of Surrounding Rock of Large Diameter Gas Extraction Drilling Through Protected Coal Pillar
In order to explore the damage law of the surrounding rock of large-diameter boreholes through the protected coal pillar,the numerical model was established by ABAQUS in the 81117 working face of Pingshu Coal Mine.The Concrete damage model yield criterion was embedded in the software,and the strength and damage factor evolution law of coal and mudstone under plastic criterion were analyzed.The results showed that the strength and damage factor of coal and mudstone have the same regular evolution form,but mudstone has higher strength character-istics.The impact of drilling and excavation on the damage of protecting coal pillar is relatively small,while the min-ing action of the working face will lead to obvious deformation and damage of the surrounding rock.The displacement of the drilling hole is about-0.08 m in 300 m of mining,and the displacement of the drilling hole reaches 0.32 m in 600 m of mining.There is the risk of penetrating and damaging the plastic zone between the top and bottom of the tun-nel and the coal pillar.
Large diameter gas extraction boreholeProtective coal pillarBorehole displacement
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