In view of the anisotropy of deformation and strength of surrounding rock at different locations(vault and hance) in loess tunnel

the anisotropy of intact loess with respect to structural strength is empatically discussed. The intact loess is sampled from Wangjiagou tunnel along Baoji-Lanzhou passenger dedicated line. A series of tests including shear test

unconfined compression test

tensile strength test are conducted on the intact loess with sampling directions of vertical and horizontal directions. Considering the influence of structure of loess on its anisotropy

the scanning electron microscope (SEM) test is also performed to analyze the main reasons leading to the anisotropy of intact loess. The results indicate that the strain ratio of horizontal direction to vertical direction decreases with the increasing of confined pressure

but firstly increases and then decreases with the increasing of normalized deviatoric stress; the peak (singularity) increases with normalized deviatoric stresses in the manner of power function. A geometric model of anisotropy of structural strength of intact loess is presented; and related strength parameters are also proposed.