Influence of shearing rate on the residual strength characteristic of three landslides soils in loess area

Abstract. In order to investigate the effect of the shearing rate on the residual shear strength of slip zone soils, a series ring shear tests were carried out on slip zone soils from three landslides in loess area at the two shearing rates (0.1 mm/min and 1 mm/min). The slip zone soil specimens used in present study were from the northwest of China. Results indicated that the shear displacement to achieve the residual stage for specimens with higher shearing rate is greater than that of the lower rate. Relationship between the residual friction coefficients and normal stress shows that the residual friction coefficients for all specimens under the lower normal stress were greater than that under the higher normal stress at two shearing rate. Furthermore, the difference in the residual friction angle ф_r at the two shearing rates, ф_r (1) − ф_r (0.1), under each normal stress level were either positive or negative values, with the maximum absolute value of ф_r (1) − ф_r (0.1) reach up to 2.218°. However, the difference ф_r (1) − ф_r (0.1) under all normal stresses was negative, which indicates that the residual shear parameters reduced with the increasing of the shearing rate in loess area.