抄録
A triaxial compression test of coarse and fine powder in low stress (lateral pressure) ranges was performed to characterize the shear fracture surfaces under varying lateral pressure (minimum stress, σ3) and to determine the principal stress difference-strain curve and internal friction factors. The results obtained were compared with those of a direct shear test. (1) The shear fracture surface under triaxial compression appears in a more definite outline with an increase in 3 and decrease in particle size. (2) Regardless of the kind of powder, the shearing process diagrams in the triaxial compression test and direct shear test show similar patterns (σ1-σ3 vs σs and τx vs δs). (3) Compared with the internal friction factors in the direct shear test under applied normal stress, the internal friction factors obtained in the triaxial compression test showed larger values for coarse powders and lower values for fine powder. However, the internal friction factors in the direct shear test under mean actual normal stress were nearly equal the actual values of the triaxial compression test.
