Surrounding rock stress state characteristics of gob-side entry driving during island mining in complex condition

Stresses, deformation and failure characteristics of surrounding rock are commonly taken into account in underground mining. At present, these characteristics are not clear in the upper and lower coal seam roadway driving along gob island, a theoretical analysis using computer numerical simulation techniques and the specific engineering practice are applied to the understanding of the roadway roof movement patterns, stress distribution and deformation of surrounding rock strata during the roadway driving and working face mining along gob island. Results show that due to effects of mining, the stress distribution characteristics are different from the normal conditions. The width of coal pillar has a great influence on the roadway deformation characteristics. The coal pillar side deformation is larger than the coal body side and the roof deformation is greater than the floor deformation during driving the gob-side roadway. During the working face mining, the roadway surrounding rock is mainly failed in shear. With the working face advancing, the dynamic pressure and influence area are increasing gradually; the convergence rate is also increasing. For the gob-side entry driving along the island mining, it should follow the surrounding rock whole section control technical approaches of Strengthen roof, Fixed side and Control floor to strengthen the supporting of roadway near the up and down corner to improve its surrounding rock strength and ensure the island working face safety in production.