Multi-scale Investigation on the Stability of Soil-Gravel Mixture Slopes Using Imaging Analyses

Gravel soil slopes were not only prevalent in nature but also widely used in engineering. Understanding the damage characteristics of gravel soil slopes and preventing slope hazards required a thorough investigation of the stability and deformation of gravel soil slopes. In this study, the stability and macroscopic deformation of slopes with varying gravel content (GC) were examined using lab tests and digital image correlation (DIC) techniques, and the rock-winding motion on the shear zone was investigated in detail by capturing the relative motion of soil particles and gravels from a micro-view perspective. In addition, the effects of loading location and slope angle were considered. The results indicated that there are two thresholds of 20% and 70% for the effect of GC on slope ultimate bearing capacity. Gravel soil slope shear damage was primarily caused by the gravel rotation at critical locations. There were at least five rock-inclusive movement patterns in the shear zone, and the primary cause of irregular damage on gravelly soil slopes was the difference in the relative movement of soil particles and gravels. High GC slopes were less sensitive to changes in LL and SA than slopes with low GC.