Experimental Study Of Strength And Deformation Anisotropy Of Compacted Loess

High-filled loess is a kind of layered compacted soil. There is a significant difference between the strength and deformation in different directions, which has an important impact on the stability and deformation of high-filled slope. It is necessary to research for the strength and deformation anisotropy of compacted loess. Based on this, the compacted loess is sampled both from vertical and horizontal, then true triaxial shear tests are conducts to investigate strength and deformation anisotropy of compacted loess.The test results show that the compacted loess has significant the anisotropy of strength and strength in the vertical direction is larger than that in the horizontal direction. The strength difference is more obvious with the confining pressure and dry density increasing. By analyzing the relation curves of between the destruct stress ratio and principal stress ratio, when the principal stress ratio is less than 0.25, the destruct stress ratio is much larger with the principal stress ratio increasing and maximum value is 1.53; and when the principal stress ratio exceeds 0.25, the destruct stress ratio decreases gradually with the principal stress ratio increasing and minimum value is 1.0. Taking experimental results into Duncan – Chang hyperbolic model, which finds parameters a and b in the vertical direction less than that in the horizontal direction when the axial pressure is applied under the same stress condition, while the initial modulus of deformation and the Poisson’s ratio in the vertical direction is greater than that in the horizontal direction, and anisotropy of Poisson’s ratio is much less significant with the water content increasing.Comparing the axial deformation in horizontal direction with vertical direction, which finds the axial deformation in horizontal direction is greater than that in vertical direction under the same stress condition, moreover the lateral strain ratio mainly ranges from 1.32 to 2.83, and the difference is much larger with the water content and dry density increasing.Comparing the lateral deformation in horizontal direction with vertical direction, which finds the axial deformation in horizontal direction less than that in vertical direction under the same stress condition, and the difference is smaller with the water content and confining pressure increasing.