Centrifuge Model Test and Numerical Analysis on Failure Behavior of a Loess – Paleosol Landslide Caused by Excavation
Abstract Many landslides are induced by excavation activities in the loess region. In this article, a loess – paleosol slope model was built and tested under 80 g centrifugal environment. Three certain angle excavations were simulated by manipulator movement. The mini pressure sensor and PIV system were utilized to monitor experimental process respectively. It can be found that the slope from excavation to failure, is liable to form the deep and shallow two sliding surfaces. The distance perpendicular to slope surface was measured as 9.6 cm for the deeper sliding surface, and 4.2 cm for the shallower one. Both of sliding surfaces are caused by the interaction of tensile failure and shear failure, specifically presented as the tensile failure concentrating on the upper part and the shear failure on the lower part. The loess slope can be split into three zones by response of excavation unloading (i.e., the sliding zone, the influenced zone and the uninfluenced zone). The failure pattern belongs to a retrogressive type with the bulging front edge and tension cracking trailing edge. The causes of the fractures on the slope top can be divided into different sections. The fracture near the slope top is induced by tension and shear force. But the fracture away from slope top is only induced by tension. In addition, the plastic zone development distribution of simulation has a good consistency with the centrifugal model deformation zoning diagram. These results can provide guidance for excavation activities in loess – paleosol slopes.