高温后大理岩的冲击力学特性试验研究

EXPERIMENTAL RESEARCH ON MECHANICAL BEHAVIORS OF MARBLE AFTER HIGH TEMPERATURES SUBJECTED TO IMPACT LOADING

利用分离式霍普金森压杆设备对经历不同高温冷却后大理岩的冲击力学特性进行试验研究,得到不同高温作用后大理岩冲击压缩的应力-应变曲线,分析高温后大理岩纵波波速的变化及在冲击荷载作用下的峰值应力、峰值应变、弹性模量随温度的变化规律。研究结果表明,高温后大理岩的纵波波速随着温度的升高近似线性下降;在800℃之前,同一冲击加载速率作用下大理岩的峰值应力随着温度的提高变化并不明显,在800℃之后,峰值应力迅速减小;在600℃之前,同一冲击加载速率作用下大理岩的峰值应变随着温度的提高无明显变化,但在600℃之后,峰值应变随着温度的提高近似线性增加;总体上,弹性模量随着温度的升高呈现降低的趋势,且经历的温度越高,弹性模量下降的幅度越大。结合高温后岩石内部微观结构特征的变化,对大理岩冲击力学特性随温度的变化进行分析。

Impact mechanical performance experiments are carried out for marble after different high temperatures under dynamic loading by using split Hopkinson pressure bar（SHPB） equipment. The stress-strain curves of specimens under impact loading are obtained. The temperature effects on the longitudinal wave velocity, as well as the peak stress, peak strain and elastic modulus of marble under impact loading are analyzed. It is demonstrated that the longitudinal wave velocity declines linearly with the increase of temperature. When the temperature is below 800℃, it does not remarkably affect the peak stress. When the temperature is above 800℃, the peak stress decreases obviously with temperature increasing. Meanwhile, the peak strain increases slightly with temperature increasing when the temperature is below 600 ℃, but the peak strain increases linearly with temperature increasing when the temperature is above 600℃. The elastic modulus under different impact velocities present the same change rule with temperature variation, decreasing approximately linearly with temperature increasing. The experiment results can be analyzed from the aspect of the changes in microstructural characteristics of marble after different temperatures.