ABSTRACT
The factors that affect the shear strength of loess can be classified into internal and external factors. The internal factors mainly include the sedimentary age, structure, void ratio, dry density, joint (density and joint surface roughness), and grain composition. The external factors include the moisture content, test methods, shear direction, drainage condition, and temperature. Direct shear, triaxial compression, ring shear, and in situ large-area direct shear tests are often used for measuring shear strength of loess. The shear strength of loess varies with different shear directions. The shear strength of the vertical and horizontal directions is almost equal for Early Lishi loess. The shear strength of vertical direction is less than that of horizontal direction for Malan loess. Generally, the horizontal shear strength is larger than the vertical shear strength for the Malan loess and Later Lishi loess, and it is opposite for the Wucheng and Early Lishi loess.
