EXPERIMENTAL STUDY ON THE ANISOTROPIC STRENGTH OF INTACT LOESS IN XINING

For studying the anisotropy of intact loess in Xining, through triaxial test with consolidated undrained at different angles in every depth, analyzing the relationship between deviatoric stress and angles in loess, meanwhile, exploring the law about the degree in anisotropy with the strain increasing. The results show that the deviatoric stress-strain relationship of loess which is near the optimum water content is strain-hardening, the most failure modes is bulging in middle part; the deviatoric stress-strain relationship of intact loess in different depths present obvious anisotropy, at the same strain, the deviatoric stress have the maximum value in the vertical direction and have the minimum value in the angle of 45°or 90°to the vertical direction. The degree in anisotropy of intact loess with the strain is connected with the stress history. When the preconsolidation pressure is small, the degree in anisotropy of intact loess decreases with the increase of the strain, and conversely, the degree in anisotropy increases with the increase of strain.