In order to investigate compression mechanical properties with strain rates varying from 600 s－1 to 2 500 s－1 on compacted clays under different compaction degrees and water contents，the specimens are subjected to axial impact with different projectile speeds by using the split Hopkinson pressure bar(SHPB) of 25 mm in diameter made by polycarbonate and a small pellet of vacuum seal cement as pulse shaper; and the validity of experiment is discussed considering the stress equilibrium and constant strain rate. The related curves of stress and strain

the relationship between dynamic stress and strain at peak with strain rates

the relationship between dynamic stress increase factor and strain increase factor at peak with strain rates

and what’more

the relationship between specific energy absorption and strain rates are also analyzed. Experimental results show that the dynamic peak stress

peak strain and specific energy absorption increase with the increase of strain rate; but the compaction degrees and the water contents have no influence on them; compaction degrees and water contents have a greater influence on dynamic stress increase factor and strain increase factor at peak; specific energy absorptions are dependent on strain rates; and the strain rate effect can be expressed by exponential approximations.