Study on activation characteristics of reverse faults by lithologic composite structures of roof

In order to reduce the threat of fault activation to coal safety production, this paper takes the 11011 working face of X Mine of a mine in Henan province as the engineering background, and studies the lithologic composite structure under different roofs by FLAC^3D three-dimensional numerical simulation software and microseismic monitoring.When the work is oriented to the reverse fault, the movement characteristics of the coal seam roof, the evolution law of the fault zone stress and the characteristics of the microseismic events during the fault crossing of the working face.The research shows that when the working face is close to the fault, the fault is gradually affected by the mining disturbance, and the degree of activation is gradually increased.When the fault is 10-20 m away, the stress of the fault zone changes significantly, and the degree of activation is the greatest:affected by the mining face Under the different lithological combination structures of the roof, the difficulty of activation of the fault is:soft and hard and soft < soft and hard hard< hard soft and soft hard< hard hard soft:in the working face mining process, the fault zone monitoring point B.The relative subsidence is greater than the monitoring point A, indicating that the activation instability occurs first in the upper part of the fault.As the working surface is approaching the fault, the fault is affected by the mining disturbance, the more micro-fractures in the rock near the fault, the fault, the more microseismic events in the nearby area, the more severe the fault activation.The research results provide theoretical basis and technical reference for the safe exploitation of coal resources in fault development areas.