冲击荷载作用下煤岩动力特性试验研究

Experimental Study on Mechanical Properties of Coal Rock Under Impact Load

为研究陕北地区硬质煤岩的动态力学性能,利用应力加载系统和分离式霍普金森压杆(SHPB)试验装置,对煤岩试件进行了基础的动、静力学特性试验,研究了其破坏机理。结果表明:静载作用下,煤岩试件多为单一裂纹破坏;而动载作用下,破坏形式比较丰富,如低应变率时的劈裂破坏和较高应变率下的压碎破坏;弹性模量与峰值应力的率相关性显著,而峰值应变的率相关性较弱;在动态加载方式下,由于加载速度过快,试件内部孔隙、裂隙、颗粒间距等缺陷闭合压实时间过短,宏观上表现为应力-应变曲线压密段缺失。

In order to study the dynamic mechanical properties of hard coal and rock in northern Shaanxi Province, the basic dynamic and static tests of coal and rock specimens were carried out by using stress loading system and split Hopkinson pressure bar(SHPB) test device, and the failure mechanism was studied. The results show that under static load, most of the coal and rock specimens are damaged by single crack, while under dynamic load, the failure forms are relatively rich, such as splitting failure at low strain rate and crushing failure at high strain rate. The correlation between elastic modulus and strain rate of peak stress is significant, but the correlation between peak strain rate is weak. Under dynamic loading mode, the closure time of defects such as voids, cracks and particle spacing is too short due to the fast loading speed, which shows that the stress-strain curve is missing on the macro level.