抄録
Many of the simple shear devices which have been used to study soil behaviour under cyclic loading do not provide sufficient measurements to determine the complete stress state of samples of soils tested in them. Consequently, certain assumptions regarding failure are normally made in interpreting the results. Tests on a dry sand under constant vertical loads were conducted in the elaborately instrumented Cambridge University's cyclic simple shear apparatus and the results of the stresses on the center of the samples are presented. The results revealed that failure in simple shear strain is initiated on the vertical planes at a very early stage of the tests. But, neither the vertical nor the horizontal planes are planes of maximum stress obliquity. The planes of maximum stress obliquity are inclined at (π/4-φ/2±ψ) to the horizontal of planes on which the maximum shear stress ratio occurs where φ is the angle of internal friction and ψ is the inclination of the principal axes of stress to the vertical planes. At low levels of shear strains the inclination of the principal axes of stress and of strain increments were, in general, non coaxial.
