EXPERIMENTAL STUDY ON DYNAMIC MECHANICAL PROPERTIES OF AMPHIBOLITES UNDER IMPACT COMPRESSIVE LOADING

In order to investigate rock dynamic compression mechanical properties with strain rate varying from 40 s-1 to 150 s-1 on amphibolites,the specimens are subjected to axial impact with different projectile speeds by using the split Hopkinson pressure bar(SHPB) of 100 mm in diameter and a thin red copper circular plate as pulse shaper;and the consistence of experiment is discussed to consider the effect on experimental result of size of the samples. The wavy curves of samples,dynamic compressive strength,dynamic strength increase factor,and the relationship between specific energy absorption and strain rate are also analyzed. Experimental results show that the dynamic compressive strength and specific energy absorption of amphibolites are strain rate dependent,and the strain rate effect can be expressed by linear approximations. The failure strain of rock increases with the strain rate;and the relationship between dynamic strength increase factor and logarithm of average strain rate is approximately linear,but no relations can be seen for the initial elastic modulus of amphibolites with strain rate. Testing and consistence of case verification experiment show that the SHPB test results of amphibolites are acceptable. The experimental method and conclusions can be used to analyze the dynamic capabilities of other brittle materials.