In-flight Excavation of a Loess Slope in a Centrifuge Model Test

An in-flight excavation centrifuge model test was conducted to investigate the behavior of a loess slope under different excavation slope angles. The displacements of the loess slope were measured using the particle image velocimetry system. Measurement results showed that the slope can be divided into several zones according to the features of the horizontal displacement. The excavation slope angles significantly affected the deformation process and the division of the slope. The term “slip zone” that described the area where strain highly concentrated when the slip surface ran through was used to analyze the failure process. The analysis results showed that the shear failure initially occurred near the excavation zone and progressed upwards and was accompanied with the tensile failure generated in the upper part of the slope. The shear failure eventually ran through the slip zone when it reached the upper tensile failure. The results of the earth pressure measurements demonstrated that the slope under excavation had undergone a stress path similar to the reduced triaxial compression tests prior to failure. It is clear that loess slopes are more likely to failure when they are influenced simultaneously by excavation and precipitation.