Characters of in-situ stress field in Huainan mine area and its influence on stability of coal roof and floor

Based on analysis of geological conditions of Huainan mine area, the distribution law of in-situ stress of the research area is studied, stress in surrounding rock of circular opening and the stability of coal roof and floor for working face under different confining pressure are discussed by using methods of testing in-situ stress, theoretical analysis and simulated calculation.It is shown that in-situ stress of Huainan mine area is represented chiefly as gravity stress field.Except locally centralized stress, there is no high tectonic stress in the research area.Lateral pressure coefficient λ is generally 0.49~1.49 and 0.92 in average, and the value λ is related with the distance between measuring point of ground surface.Its law is that lateral pressure coefficient λ is greater in the superficial part, change range of the value λ also larger, but in deep, lateral pressure coefficient λ is lower, change range of the value λ is also smaller.Stability of coal roof and floor is closely related with the size of lateral pressure coefficient λ.With lateral pressure coefficient λ increasing, vertical displacement of coal roof decreases continuously and coal roof strata forms easily structural balance and keeps advantageously stability.Contrasting to coal roof, vertical displacement of coal floor increases continuously and floor heave is formed easily as lateral pressure coefficient λ increases.The research results are of significant value to the mining design and strata control of underground.