Study on Seismic Waves Affected to Dynamic Stability of Coal Pillar in Strip Mining

Under the seismic waves, blasting seismic and other dynamics stress effects, the responses of the goaf would have the influences to the mine safety min ing, the surface ground subsidence control and others.Based on the elastic mechanics plane wave theory, the paper had a discussion on the mechanism of coal pillar st ability lost caused by the seismic waves.The finite difference method was applied to the static calculation of the goaf in a strip mining.Based on the circumstance, a furt her analysis was conducted on the dynamics responses of the coal pillars in the goaf under the seismic wave effect.The study showed that under the static condition, th e coal pillars in the goaf would be in stable status and could effectively support the rocks above.Under the seismic wave effect, the yield degree of the two sides along t he coal pillar would be increased, the stress would be reduced and the stress of the coal pillar would be transferred to the middle part of the coal pillar.The plastic zone would be expanded to the middle part and to the roof and floor and the stability of the coal pillar would be reduced.Therefore, the seismic and dynamic load affected to t he stability of the goaf should be considered in the mining design.