Mechanical behaviour and seepage characteristics of coal under the loading path of roadway excavation and coal mining

Abstract

The mechanical behaviour and seepage characteristics of coal under the mining engineering disturbance are of great significance to prevent gas disasters. Based on the geological conditions of the No. 12 mine of the China Pingdingshan Mining Group, the mechanical seepage experiments of coal under the stress path of roadway excavation and coal mining were carried out. The experimental result shows that: The coal in fracture zone is most strongly affected by the roadway excavation. The samples showed obvious expansion phenomenon, and their cracks were the most complex. They formed effective permeability before the peak strength, and their permeability was the largest; the coal in disturbance zone is less affected by roadway excavation, and the coal samples formed effective permeability after the peak strength. Their permeability was smaller than the samples in fracture zone; the coal in original rock stress zone is only affected by coal mining, and its crack growth degree is the lowest. The coal samples formed stable permeability in the residual strength stage, and their permeability was the smallest. In practical engineering, special attention should be paid to the sudden gas gushing caused by the sudden increase of coal seam permeability, which will cause gas disaster.

Keywords

• gas disaster
• seepage characteristic
• coal
• roadway excavation
• coal seam mining