Stability of a Compacted Sand Slope Model Subject to Crest Load

Abstract

Studying the stability of slopes is of great interest since it is associated to various geotechnical applications, e.g., access embankments and landslide mitigation. This paper describes the research conducted to determine the failure load applied at the top of excavations in sandy soils during the construction of deep digs without the use of retaining systems. An experimental program was performed to measure the failure load of ten laboratory-compacted sand slope models that were constructed using different slope angle values and different locations for the applied loading, which consisted of an imposed uniform rate of vertical displacement at the top of the slope. Then, a three-dimensional (3D) numerical model of the laboratory tests was developed to simulate the observed behavior during the experiments by the Plaxis 3D code. The Mohr–Coulomb (MC) and hardening soil (HS) models were used to describe the behavior of the compacted sand. The results showed that the 3D numerical simulations based on the MC model were able to predict the measured failure load within a relative difference of less than 11% for nine tested slope models, while the HS model was better in predicting the measured failure load (a relative difference of 3.5%) for only one experimental setup when the slope angle was equal to 35°. Furthermore, analytical prediction of the failure load using the yield design theory (YDT) permitted the validation of the log-spiral curve describing the observed failure surface for the tested sand slope models.