Abstract
In this study, direct shearing tests of Sanjome andesite were carried out under three shear displacement rates (5×10-5, 5×10-4, 5×10-3mm/s) and four normal stresses (10, 20, 30, 40MPa) by a servo-controlled testing machine. When shear displacement rate was increased by a factor of 10, increment of shear strength was about 1.2MPa. Relative increment against shear strength was about 6% that almost coincides with the values obtained in uniaxial tension and compression tests. It can be said that loading rate dependency of shear strength is similar to those of uniaxial tensile and compressive strength. The relationship between failure criteria and loading rate dependency was also discussed.
