曹家滩煤矿高强度开采覆岩地表变形破坏规律研究OA

Under high-intensity mining conditions,the structural response of overburden is severe,significantly affecting the safety of surface structures.Taking the 122104 super-large mining height working face of Caojiatan Coal Mine in the Yushen Mining Area of Northern Shaanxi as a case study,a high-frequency dynamic monitoring network for surface subsidence was established.Data on surface subsidence and cracks evolution during the advancement of the working face were collected,systematically revealing the spatiotemporal evolution characteristics of surface movement and deformation under large mining height fully mechanized mining conditions.Monitoring results indicate that surface movement and deformation were intense under the influence of super-large min-ing height.The maximum surface subsidence value reached 4 770 mm,with a peak subsidence rate of 756.7 mm/d.The surface sub-sidence process exhibited distinct stage-specific characteristics,with the severe deformation stage accounting for 92.5%of the total subsidence.The maximum subsidence rate coefficient reached 3.38,while the initiation distance,advance influence distance,and lag distance of maximum subsidence rate were 100.0 m,153.8 m,and 137.0 m,respectively.Surface cracks generally exhibited a"C"-shaped distribution,occurring primarily 40-50 m behind the advancing working face,with a significant correlation observed between crack development locations and the advance rate.To further explore the response mechanism of overburden structure,a three-di-mensional discrete element model of the overburden was constructed.Model parameters were inversely calibrated based on meas-ured data,and the evolution path of the overburden from initial disturbance to overall failure under mining-induced disturbances was simulated.The spatial distribution ranges of the caved zone and fractured zone were obtained,reflecting the intense failure character-istics of the overburden.