Strain rate dependent strength and stress–strain characteristics of a welded tuff

Results of 61 uniaxial compression tests on the welded Topopah Spring tuff are presented. The tests were carried out under constant strain rates at room temperature. Stress–strain analysis indicates that dilatancy and compaction start at about 50% of ultimate strength. A sudden stress drop occurs at about 90% of the ultimate strength, which indicates the onset of specimen failure. Both strength and peak axial strain decrease with strain rate as power functions. Based on the strain rate dependence of strength and peak axial strain, it is inferred that the elastic modulus is strain rate dependent. A relationship between stress, axial strain, and axial strain rate is developed. The parameters in this relation are estimated using multivariate regression to fit stress–axial strain–strain rate data.