Deformation and failure mechanism of high sticking loess slope

Loess high sticking slopes have become a popular construction solution for engineering land in loess ridge landform area. The failures of those slopes have encouraged the studies on deformation and failure mechanisms of such artificial slopes. In this research, a high sticking slope failure is used as a case study. Based on the in-situ investigation and geological engineering survey, the stratigraphic structure features and impact factors of slope stability are analyzed. According to the analysis results, the corresponding laboratory tests are conducted, such as compacted loess wetting compression tests, deeply buried Q₂ loess collapsibility tests, and loess triaxial tests with CTC and RTC stress paths. The deformation and failure mechanisms of high loess sticking slopes are studied from the in-situ and laboratory test data. The results indicate that the fluctuation of bed stratum causes various fill thicknesses, which further induce differential settlements and cracking on the slope shoulder. Water infiltration into the crack will then trigger deformation and failure. The failure mode of high sticking slopes is summarized: the differential settlement induced by consolidation of compacted loess and collapse of Q₂ loess under high pressure causes cracks of slope shoulder→water infiltration into cracks softens the compacted loess→the initial sliding surface forms in the middle of slope→the front part of loess fails under wetting CTC stress path→the back part of loess fails under wetting RTC stress path→the locking section loess failes under wetting CTC stress path→the whole slope fails. These results are helpful for understanding the formation and evolution of failure of high loess sticking slopes, and may provide technical support to the treatment of loess slope stability.