煤矿砂岩动态力学性能试验与分析方法研究*

为研究动载荷作用下煤岩体测试与分析方法，基于直径50 mm分离式Hopkinson试验装置，采用半导体应变片和电阻应变片2种方法采集透射波，开展淮北矿区典型砂岩动态冲击压缩试验，采用二波法和三波法分别计算得到砂岩试件的应变率、应力和应变峰值等动态力学参数以及能量耗散特征，分析不同应变片种类和计算分析方法的差异性。结果表明:不同计算分析方法得到的应力应变曲线形态基本一致，2种应变片采集的数据可以组合使用；与电阻应变片相比，半导体应变片灵敏系数高，由其采集数据计算得到的应力值高、峰值应变小、应力应变曲线光滑，三波法处理数据具有更高的可靠性；根据2种应变片测试数据计算得到试件应变率、动态强度及峰值应变均随冲击速度的增加而增加，试件吸收能量变化也具有一致性，能量耗散率误差在10%以内。研究结果可为煤矿软岩动态力学性能测试与分析提供参考。

Research on dynamic mechanical performance test and analysis method of coal mine sandstone

In order to study the test and analysis method of coal and rock mass under the dynamic loading,based on a separated Hopkinson test device with the diameter of 50 mm,the transmission wave was collected by both methods of semiconductor strain gauge and resistance strain gauge,and the dynamic impact compression tests of typical sandstone in Huaibei mining area were conducted.The two-wave method and tri-wave method were used respectively to calculate the dynamic mechanical parameters such as strain rate,stress and strain peak values and the energy dissipation characteristics of the sandstone specimens,and the difference between different strain gauge types and calculation and analysis methods were analyzed.The results showed that the shapes of stress-strain curves obtained by different calculation and analysis methods were basically the same,and the data collected by the two strain gauges could be used in combination.Compared with the resistance strain gauge,the semiconductor strain gauge had higher sensitivity coefficient,and calculation results by its collected data presented higher stress value,smaller peak strain and smoother stress-strain curve.The tri-wave method had higher reliability in the data processing.With the increase of impact velocity,the calculation results by the testing data of the two strain gauges were all increased,including the strain rate,dynamic strength and peak strain of the specimens.The absorbed energy variation of the specimens was also consistent,and the error of energy dissipation rate was within 10%.The research results can provide reference for the dynamic mechanical performance testing and analysis of soft rock in coal mine.