节理接触面对应力波传播影响的SHPB试验研究

SHPB EXPERIMENT ON INFLUENCE OF CONTACT AREA OF JOINTS ON PROPAGATION OF STRESS WAVE

为探讨岩体的节理接触面积对应力波传播规律的影响,采用分离式霍普金森压杆试验装置开展试验研究,分析不同接触面积比的节理的动态力学特性以及节理的接触面积几何分布对应力波传播特性的影响。人工切槽的岩块与完整岩块组合得到不同接触面积比的节理岩块作为试样。通过一系列的实验,得到以下的结论:节理的接触面积比、接触面积分布和冲头冲击速率不仅影响节理岩块的动态力学特性而且影响应力波的传播。应力波的透射系数与冲头冲击速率、节理面大小及相对密集度(即接触面分布离散和接触面分布紧凑)有关;当节理接触面的几何相对密集度一定时,应力波透射系数随着节理接触面积比的增大呈线性增长,且透射系数随冲头速率的增大而增大;此外,相对于节理接触面积小但分布离散的岩体,应力波通过接触面积大、分布紧凑的节理的衰减更为明显。

Split Hopkinson pressure bar(SHPB) apparatus was adopted to investigate the effect of the contact area of rock joints on stress wave propagation in this study. The research focused on two aspects,the dynamic property of joints with different contact areas and the stress wave propagation across joints with different contact distribution forms. Each sample was made of two rock blocks,one with an artificial cut surface. A series of tests were carried out and it was found that the impact velocity,the contact area ratio and the relative intensity degree of joint surface area apparently affected the dynamic stress-strain relation of rock masses and the stress wave propagation across rock masses. The transmission coefficient increased with the increase of contact area ratio of joints and the impact velocity. The transmission coefficient of the joints with a small and dispersed contact area was higher than that with a large and clustered contact area.