Abstract: The stress path and the moisture content are the important aspects that governing the deformation characteristics of the collapsibility of loess samples. A modified stress-controlled direct shear device was used to analyze the shear deformation of the loess caused by the change of moisture content under the condition of the constant stress, and the wetted shear deformation characteristics of loess were discussed. Wetted shear tests under different normal pressures, shear stresses and dry densities were carried out. The results show that the soil sample tends to fail when the combined value of the stress and the amount of water used for the moisture content reaches a certain value. Under the same normal pressure, when the shear stress value is small, the soil sample will not have a wetted shear failure mode. When the shear stress is greater than a certain value, the sample tends to fail when the moisture content inside the soil sample reaches a certain value. Under the same stress conditions, the change of the wetted shear displacement with the wetting moisture content of soil samples with a low dry density was higher than that of soil samples with a higher dry density.

Key words: Loess, Wetted Shear Deformation, Stress Path, Stress-Controlled Direct Shear, Direct Shear Test