Effect of Dry–Wet Cycles on the Shear Strength of Weathered Red Sandstone Soil

摘要

Dry–wet cycles can significantly modify the mechanical behavior of soil, especially the unsaturated soil shear behavior, which is particularly important for slope stability analysis and safe engineering design. In this study, direct shear tests were performed to investigate the shear behavior and strength characteristics of weathered red sandstone (WRS) soil under multiple dry–wet cycles. The WRS soil strength decreases with increasing number of dry–wet cycles and the first dry–wet cycle has the strongest influence on the soil strength, accounting for more than 50% of the total strength attenuation rate after the first five dry–wet cycles. The WRS soil strength also decreases with increasing dry–wet cycle amplitude; large dry–wet cycle amplitudes aggravate the effect of the dry–wet cycle number on the soil shear strength.