Strength Characteristics of Loess Under Large Shear Displacement

To study the strength characteristics of loess under large shear displacement, the repeated shear test was conducted in the laboratory. To better understand the corresponding mechanism of strength variation, three or four samples with different moisture content was prepared, and different vertical pressure was applied; with the help of the experiment equipments, peak strength and residual strength was obtained simultaneously. By analyzing the results of the shear experiments, we found that the peak strength and residual value is little higher under natural moisture content, and along with saturation degree increased, c value decreased rapidly while the internal friction angle (φ) varied a little. Therefore the following conclusions can be concluded: viscous resistance of soil decreased sharply mainly due to moisture content increased, which in turn resulted in decreasing of internal friction forces. Moreover, after the undisturbed soil samples fully saturated, the bridge connection becomes weaken, and soluble salts dissolve gradually, because of these the structural strength decreased sharply. For identical soils, the residual strength is less than its peak strength.