动态加载下饱水煤样力学特性及能量耗散规律

Mechanical properties and energy dissipation law of saturated coal samples under dynamic loading

为探究饱水煤样在动态加载下的力学特性和能量变化特征,采用直径50 mm的分离式霍普金森杆装置(SHPB)对饱水和自然状态2种煤样开展冲击加载试验,分析含水状态对煤样的动态强度、应变、损伤和能量传递效率的影响。结果表明:在应变率14.25~59.57 s^(-1)内,水体对煤样动态强度具有双重作用,表现为低应变率弱化和高应变率强化;相同冲击载荷下,自然、饱水煤的变形差异显著,最大应变相差38.46%;煤样含水状态显著影响能量传递效率,其中自然和饱水煤样的能耗密度均与入射能呈线性增长关系,且自然煤能量反射率大于饱水煤能量反射率,自然煤透射率小于饱水煤透射率,耗散率二者近似相等。

To investigate the mechanical properties and energy variation characteristics of saturated coal samples under dynamic loading,a 50 mm diameter split Hopkinson rod device(SHPB)was used to conduct impact loading tests on both saturated and natural coal samples,and to analyze influence of water content on the dynamic strength,strain,damage,and energy transfer efficiency of coal samples.The results show that within the strain rate range of 14.25 s^(-1) to 59.57 s^(-1),water has a dual effect on the dynamic strength of coal samples,manifested as low strain rate weakening and high strain rate strengthening;under the same impact load,there is a significant difference in deformation between natural coal and saturated coal,with a maximum strain difference of 38.46%;the water content of coal samples significantly affects the energy transfer efficiency,where the energy consumption density of both natural and saturated coal samples increases linearly with incident energy,and the energy reflectance of natural coal is more than that of saturated coal,and the transmittance of natural coal is less than that of saturated coal,and the dissipation rate is approximately equal.