The Damage Characteristics of Coal Seam Floor Caused by the Fracture of Hard Limestone Roof
In order to study the influence of hard limestone roof fracture on the deformation and damage of coal seam floor,the 111107 working face of Qiuji Coal Mine in Huanghebei Coalfield is taken as the background.Based on the fracture dynamic load stress function of roof rock body,the damage process of goaf floor caused by the fracture of hard limestone roof is simulated by FLAC3D.The damage characteristics of goaf floor under different dynamic load amplitude values are com-pared.Based on deep hole energy gathering blasting presplitting technology,a blasting roof cutting scheme is designed to provide guarantee for the safe mining of hard limestone roof working face.The simulation results show that there is a significant increase in the damage range and depth of floor before and after the dynamic load action,with the maximum damage depth of the floor reach-ing 12 m.After the end of the dynamic load action,residual stress waves continue to affect the floor of the stope until the limestone roof fractures for 150 ms,and the dynamic response of the floor of the stope finally ends;As the amplitude value of dynamic load increases,the damage range of floor gradually increases;Under the same duration condition,when the amplitude value is less than 10 MPa,there is no significant change in the damage of the floor before and after the dynamic load action;When the amplitude value is greater than 10 MPa,there is a significant change in the damage of the floor before and after the dynamic load action.
hard limestonefracture of roofhole energy gathering blastingtop cutting and pres-sure relief
万方数据
维普
