Three-dimensional geological structures and sliding factors and modes of loess landslides

摘要

Loess environments such as the Chinese Loess Plateau are geologically fragile because of their great thickness, loose structure, crisscrossing ravines and gullies, broken terrain, dry climate, severe erosion and unevenly distributed rainfall. As a consequence, loess areas are highly prone to environmental problems and geological hazards. The geological structure of the loess is one of the main factors that controls occurrence of these geohazards. This study investigated the mechanism of loess landslides and their sliding control mode from the perspective of their geological structure. Using this mechanism, a three-dimensional geological model of loess landslides was established. The study shows that the structural planes in loess divide a complete slope into separate blocks, which enables the fast and deep infiltration of surface water via seepage channels and reduces the shear strength of the soil mass, inducing landslides. The development and formation of loess landslides are primarily controlled by structural planes and influenced by infiltrated water softening the structural plains. Various types of structural planes may combine and form structural bodies of different types and scales, which control the type, depth and scale of loess landslides.