Study on the Damage Law of Mechanical Properties of Coal-Rock Combinations under Different Misture Contents
Shallow buried water rich coal seams are long-term affected by groundwater seepage erosion in the overlying rock water conducting cracks,and the mechanical damage and deterioration of the water resistant coal rock columns and inter stage columns left in the mine under the action of water and rock occur.Mining activities further accelerate the damage process and directly affect the stability and safety production of the working face.Taking the coal rock mass of Jinjie coal mine in Yulin,Shaanxi Province as the research object,a sandstone-coal-sandstone(S-M-S)combination was developed.We conducted uniaxial compression tests under varying moisture conditions.This characterized moisture absorption,evolution of mechanical behavior and acoustic emission-based damage.Scanning electron microscopy revealed the internal structural degradation mechanisms.The research results indicate that the water absorption rate of coal rock combinations decreases continuously with the increase of immersion time;The water rock interaction has a significant deterioration effect on the compressive strength and elastic modulus of coal rock combinations,and the weak residual strength of the composite decreases continuously with the increase of moisture content,and the rate of strength damage accelerates continuously with the increase of moisture content;Acoustic emissions and cumulative counts were heavily attenuated,accompanying the evolution of damage.The water rock interaction causes the passivation of the primary chain of the internal structure of the combination,the expansion of cracks,and a significant change in the form of fractures.The research results can provide guidance for the prediction and evaluation of water damage in coal rock pillars under the influence of mining.
mine water prevention and controlcoal-rock combinationsmechanical propertiesmoisture contentacoustic emission
万方数据
维普
