煤系岩石冲击倾向性试验研究

Experimental investigation of the bursting potential in coal measures rocks

煤系岩石冲击倾向性是煤、岩介质的固有属性。本文通过煤系岩石显微定量分析和冲击倾向性试验研究,建立了碎屑岩的岩石学特征与其宏观力学性质和冲击倾向性之间的相关关系。研究结果表明,碎屑岩的岩石学特征对其宏观力学性质和冲击倾向性具有重要影响作用,随着碎屑颗粒含量的增加,岩石的强度和刚性增强,岩石的脆性增大,弹性能指数和冲击能指数增加,岩石在轴向应力作用下达到峰值强度以后直到完全破坏的持续时间变短,冲击倾向性增强。随着碎屑颗粒粒径的增大,印由砂质泥岩、粉砂岩向砂岩过渡,粗粒的粒柱状矿物逐渐增加,而细粒的片状矿物逐渐减少,岩石的强度和刚性增强,在集中应力作用下,弹性能指数增大,发生脆性破坏的可能性增大及破坏持续的时间变短也更猛烈,岩石的冲击倾向性增强。

The bursting potential of coal measures rocks is the inherent attributes of coal and rocks. By using micrographic quantitative analysis and testing research of the bursting potential in coal measures rocks, the correlations of lithological characters of clastic rock and its macro mechanical properties and bursting potential are established. The results show that the petrographic characteristics of clastic rock have an intrinsic influence on its macro mechanical properties and bursting potential. With the increasing of the rock detritus content, the uniaxial compressive strength and Young＇s modulus increase; the elastic strain energy index and bursting energy index of studied the rocks increase; the duration of failure decrease. And the brittleness of rock is strengthened and the burst potential increases. With the increasing of average size of detritus grains in rock, from argillaceous sandstone, siltstone to sandstone, the granular minerals gradually increase and the sandwich-flaky minerals decrease, which results in the strengthening of rock stiffness and the reducing of rock plasticity. Therefore, under the uniaixal compressive condition, the uniaixal compressive strength and Young＇s modulus are increasing, then the elastic strain energy stored in rock gradually increases, the failure duration decreases and the bursting potential increases with its increasing average size of detritus grains.