Strength and deformation behavior of Shanghai andesite under various strain rates in uniaxial loading test

Uniaxial compressive test was carried out on Shanghai andesite herein under low (0.00001-0.1/s) and medium (1/s) strain rate for the purpose of investigating the strain-rate-dependent deformation and strength characteristics of andesite that was found in Sheshan town of Songjiang region Shanghai in China. The testing results were used to study the stress-strain response of Shanghai andesite and the effect of strain rate on peak strength, strain at peak strength and the modulus of elasticity of Shanghai andesite. In addition, the effect of sample size of shanghai andesite on peak strength is also surveyed. From the above testing results, it is concluded that with increase in strain rate that is exactly controlled by testing machine the peak stress is also increased, by approximately 10% when one-unit of logarithmic magnitude is added. And the strain at peak stress and the modulus of elasticity of the eruptive rock also increase to some degree with the increase in rate of strain. Inversely, the peak stress decreases with the decrease in rate of strain. In addition, for the effect of sample size, the peak strength increases with the increase of sample size with all else being equal.