ABSTRACT
The effect of stress level on the compressive strength of rock samples is researched using Tephrite samples subjected to cyclic loading. Four sets of stress level (% 20, %30, %40 and %50 of uniaxial compressive strength) were applied for cyclic loading tests on dry and saturated samples by 200 tons servo-hydraulic testing rig. The compressive strength of the rock by different stresses were determined under constant frequency and number of cycles at failure. The results of the cyclic loading tests indicate that stress level has significant influence on the uniaxial compressive strength. An increase in stress resulted in a decrease in compressive strength proportionality. In the case of the saturated samples, it was found that compressive strength reduced by approximately 25 per cent.
