实时温度下中细粒花岗岩动力响应与吸能特性试验研究

 基于改进的分离式霍普金森压杆，研究实时温度下中–细粒花岗岩的动力响应与吸能特性。结果表明：温度在20 ℃～500 ℃下，花岗岩全应力–应变曲线的弹性、塑性与应变软化3个阶段特征明显，700 ℃时的应力–应变曲线出现塑性屈服平台；应变率增加，岩石抗压强度增大，但随温度的升高应变率效应逐渐减弱；温度和应变率对岩石弹性模量的影响规律均不明显；应变率增加会使岩石单位体积的能量吸收能力提高，但不同温度下应变率对单位体积吸能的影响效果有较大差异；500 ℃及以下时峰值应变的应变率效应比较接近，但700 ℃时峰值应变的应变率敏感系数大幅增加；采用相同气压加载时，发现不同温度下应变率所处范围差异较大，而且气压对应变率的影响系数也不相同；500 ℃及以下，随应变率增加试样破坏形式从劈裂过渡到碎裂，700 ℃时试样则呈粉碎性破坏。

Experimental study on dynamic response and energy-absorbing property of medium-fine grained granite under actual temperature

The dynamic response and energy-absorbing property of medium-fine grained granite under the actual temperature were studied using the modified split Hopkinson pressure bar(SHPB). The complete stress-strain curve of the granite displayed three notable stages of elastic，plastic and strain-softening in the range of 20 ℃–500 ℃. When the temperature rose to 700 ℃，the plastic yielding platform in the curve appears. A rise in the strain rate caused the increase of the compressive strength of granite，but the effect of the strain rate decreased gradually as the temperature increases. Neither the temperature nor the strain rate showed the influence patterns on the elastic modulus. The increase of strain rate raised the energy-absorbing capacity of per unit volume(Ev)，but the effects of strain rate on the value of Ev were quite diverse under the different temperatures. When the temperature was less than or equal to 500 ℃，the effects of strain-rate on the peak strain are relatively close，whereas the strain-rate sensitivity coefficient of the peak strain increased significantly at 700 ℃. Under the same loading pressure，the strain-rate ranges of the specimens treated under different temperatures differed widely，and the influence coefficients of the pressure were also distinct. The failure mode of specimen under the increasing strain rate at 500 ℃ and below changed from the axial splitting to fracturing. At the temperature of 700 ℃，all the specimens were pulverized.