Abstract: Split Hopkinson pressure bar tests (SHPB) were carried out to investigate the strength characteristics of granite residual soil under high strain rates comparing to that under common strain rates. Stress-strain curves and strength properties under various strain rates were obtained and found to be strain-softening. The failure strain ?af increased with increasing the strain rate. The increase of ?af was more evident at high strain rates. The peak strength of granite residual soil was found to be rate-dependent, and the peak strength increased linearly with the increase of strain rate, but the fitting relationships under low and high strain rates were different. The coefficient of strain rate sensitivity m was proposed for the quantitative evaluation of the correlation. The results show that the dependence decreases with the increase of strain rate. The value of m at low strain rate is 26.694, while only 0.013 at high strain rate. Judging from the test results, the high-speed impact load is generally harmful to the soil. The research will lead to a deeper understanding of the impact damage mechanism and provide technical guidance for relevant construction.

Key words: impact loading, granite residual soil, split Hopkinson pressure bar, strain rate, strength, coefficient of strain rate sensitivity