不同损伤程度花岗岩在冲击荷载作用下的动态力学特性

Dynamic Mechanical Properties of Granite with Different Damage Degrees under Impact Loading

为研究不同初始损伤下花岗岩的动态特性,通过理论分析定义了岩石损伤程度计算,利用霍普金森杆设备分别对损伤程度为13%、21%、28%、37%、40%、49%岩样进行临界气压冲击试验研究。试验结果表明:变形模量较好反应了岩样的损伤程度,岩样损伤程度随变形模量的减小在增大,其抗冲能力在减弱;不同损伤程度岩样在冲击荷载作用下,随损伤程度增大,峰值应力逐渐减小,而动态峰值应变、破坏应变和应变率有递增趋势;不同损伤程度试样破坏模式有明显的不同,岩样破坏块度随损伤程度的增加更趋于破碎。

In order to study the dynamic characteristics of granite under different initial damage,the damage degree of rock is defined by theoretical analysis.The critical pressure impact tests for rock samples with damage degree of 13%,21%,28%,37%,40% and 49% are carried out by Hopkinson bar equipment.The test results show that the deformation modulus reflects the damage degree of rock samples well.The damage degree of rock samples increases and the impact resistance of rock samples decreases with the decrease of deformation modulus.The peak stress decreases with the increase of damage degree under impact load,while the dynamic peak strain,failure strain and stress decrease with the increase of damage degree.The failure modes of samples with different damage degrees are obviously different,and the fragmentation of rock samples tends to be more fragmented with the increase of damage degree.