SHPB试验中高温下岩石变形破坏过程的能耗规律分析

ANALYSIS OF ENERGY DISSIPATION RULE DURING DEFORMATION AND FRACTURE PROCESS OF ROCK UNDER HIGH TEMPERATURES IN SHPB TEST

利用带高温装置的φ100 mm分离式Hopkinson压杆试验系统进行不同高温下大理岩的SHPB试验,分析岩石在冲击破坏过程中的能量耗散特征,探讨冲击加载速率、入射能等对高温下大理岩能耗特征的影响,分析冲击破碎分维及破碎块度与能量耗散的内在联系。研究结果表明:同一高温下大理岩破碎的比能量吸收随着加载速率、入射能的增加均近似线性增加;破碎分维随比能量吸收的增加近似线性增长,而平均破碎块度随比能量吸收的增加逐渐减小,大致呈指数关系。同一高温下岩石的冲击破坏过程中,比能量吸收愈大,岩石的平均破碎块度就愈小,分形维数就愈大,岩石的破碎程度也就愈剧烈。从能量耗散的角度可以较合理地反映岩石变形破坏的全过程。

Experimental studies of marble under different high temperatures and impact load are carried out by using the high temperature split Hopkinson pressure bar(SHPB) apparatus of 100 mm in diameter. The characteristics of energy dissipation and the influence of impact velocity and incident energy on the energy dissipation of marble during the impact process are analyzed. The relationships between the fractal dimension, average fragment-size and energy dissipation of marble are also investigated. The test results show that the specific energy absorption increases linearly as the impact velocity and incident energy increase at the same high temperature. Meanwhile , the fractal dimension increases linearly and the average fragment-size decreases exponentially with the specific energy absorption increasing. Under the same high temperature,the greater the specific energy absorption is,the smaller the average fragment-size is,the greater the fractal dimension is,the more severe fragmentation is. Consequently,the deformation and fracture process of marble can be reasonably reflected from the viewpoint of energy dissipation.