Study On The Effect Of Mining And Excavation On The Mechanical Propetries Of Coal Seam And The Gas Occurrence

In this paper, compositive research techniques including of in-situ measurement, numericalsimulation and theoretical analysis are carried out to investigate the effect of mining and excavationon the mechanical properties of coal seam and the gas occurrence. The results show that,mechanical properties of gob-side coal are controlled by geometrical morphology of the stress shell,the stress field; destroyed field and displacement field depend on the mechanical state of the stressshell base. The continuous concentrated stress appears ringwise in the surrounding rock of roadwayin coal mass, and extends to the front of heading face, appearing as blind tubular shape. Withgob-side roadway driving, the interaction between excavation disturbance stress and gob sideabutment pressure result in the coupling effect of dynamic and static stress field, and theasymmetry of mechanical properties of surrounding rock. Before heading face, coal seam gaspressure is controlled by coal stress, and proportional to it. The surrounding rock is disturbed byexcavation, which is proportional to the roadway driving. The mechanical properties and stabilityof surrounding rocks can be improved by enhance the roadway driving speed suitably.Dynamicdisaster prevention can be realized by controlling coal stress and improving the state of the gasoccurrence. The results provide important references on the coal mining safety, the undergroundpressure control and dynamic disaster prevention of heading face, and the theory of undergroundpressure of heading face.