Landslides triggered by excavation in the loess plateau of China: A case study of Middle Pleistocene loess slopes

Abstract

The frequent occurrence of catastrophic landslides caused by excavation in a loess slope is one of the commonly encountered engineering problems in the Loess Plateau. Middle Pleistocene loess slopes were selected as a case study for current research. The distribution of excavation-induced loess landslides was studied by field investigation. On the basis of centrifuge model tests, the deformation features and failure mechanism of a homogeneous loess slope and a double paleosol-interlayer loess slope under different excavation slope angles were analyzed and compared. It was shown that the response of horizontal earth pressures in the lateral region of the excavation zone has a close relationship with the failure of the slope. Displacement measurements showed that the deformation stages of loess slopes due to excavation are independent of the paleosol interlayer. The excavation slope inclinations and soil properties significantly affected the failure process and division of the slope. The characteristics, that excavation-induced loess landslides always occur in hysteresis and abruptness, were interpreted by the analysis of the failure process. The influence of blade penetration during the excavation performed was quantitatively estimated. Finally, based on the result of stress path tests, an improved unloading constitutive model was proposed to simulate the deformation of soils in the lateral and bottom of the excavation area.