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

Abstract

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 фr at the two shearing rates, фr (1) − фr (0.1), under each normal stress level were either positive or negative values, with the maximum absolute value of фr (1) − фr (0.1) reach up to 2.218°. However, the difference фr (1) − фr (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.

Geophysical and Geotechnical Evaluation of Landslide Slip Surface in a Residual Soil for Monitoring of Slope Instability

“…This was corroborated with the lowest internal friction angle of 30° obtained for Test C in direct shear test, which clearly indicates a slip zone or surface, according to Lian et al. (2018), for slip zone soils that were sheared using a high shearing rate of 1 mm/min attained lower friction angle than a lower shearing rate and vice versa. This lowest fiction angle of 30° in Test C soil sample occurred within 3.0 m depth, which coincides with the interpreted slip surface on the ERT model (Figures 4 and 5).…”

“…Geotechnical engineering studies of the mechanical properties of residual soil with direct shear test are very important for analyzing, evaluating, and monitoring of slope instability (Chang & Phantachang, 2016; Lian et al., 2018). Knowledge of engineering characteristics of residual soil may offer significant information about the slope soil shear strength parameters and its bearing capacity (Han et al., 2020; Wei et al., 2019).…”