A study on the measurement of the shear strength of the Seoul granite by the multiple direct shear test

This paper describes multiple failure state direct shear test for the purpose of determining failure envelope. The major concern in this paper is the behavior of artificial joint specimen under the shear and normal stress. In a multiple failure state direct shear test, the specimen is preserved in a state of perpetual sliding while the shear and normal stress are being stepwise changed. In this test the normal stress was forced respectively 1.0, 2.0, 3.0 and 4.0MPa. In a individual direct shear test c(cohesion force) was 2.7MPa and phi(internal friction angle) was 58.0 degrees meanwhile c,phi was 1.9MPa and 59.1 degrees in multiple direct shear test. This paper intends to confirm the use of multiple direct shear test deciding strength constants c and phi with one specimen.