瓦斯对煤冲击倾向性影响的试验研究

为研究瓦斯对煤冲击倾向性的影响,在不同瓦斯压力下测定了煤的冲击倾向性指标,分析了含瓦斯煤样在多级循环加载和单轴应变加载时能量积聚与耗散情况。研究结果表明:在孔隙瓦斯压力和吸附瓦斯共同作用下,煤样冲击倾向性指标由强向弱或由弱向无转变;瓦斯降低了煤样的强度,在多级循环过程中由损伤和塑性变形引起的耗散能增加,煤样储存弹性应变能的能力下降,完全破坏时煤样盈余能量减少,瓦斯弱化了煤的冲击特性;伴随瓦斯压力的增加,能量跌落系数逐渐变大,表明瓦斯致使煤样的破坏形式由脆性向脆塑性转变;基于瓦斯对煤的冲击倾向性和破坏形式的影响,在含瓦斯煤层冲击倾向性测定和冲击危险性评价过程中,应充分考虑瓦斯对煤层冲击特性的影响。

Experimental research on the influence of gas on coal burst tendency

In order to study the influence of gas on coal burst tendency,the burst tendency index of coal samples was measured under different gas pressures,the energy accumulation and dissipation of coal samples under multi-stage cyclic loading and strain loading were analyzed.The results show that under the combined action of pore pressure and adsorbed gas,the burst tendency index of coal sample changes from strong to weak or weak to direct；the gas reduces the strength of the coal sample,and the dissipation energy due to the damage and plastic deformation increase during the multistage cycling process,the ability of coal samples to store elastic strain energy decreases,when the coal sample is completely destroyed,the surplus energy decreases,thus,the gas weakens the burst performance of coal.With the increase of gas pressure,the energy drop coefficient becomes larger,it indicates that the failure form of coal samples changes from brittle to brittle-plastic.Based on the influence of gas on burst tendency and the form of failure of coal,when measuring the burst tendency and evaluating the rock burst risk of gas containing coal seams,the influence of gas on the burst performance of coal seams should be taken into a full consideration.