Similitude Model Experiments for Studying Slip-Buckling Failures in High and Steep Side Slopes Set along the Bedding Plane of Layered Rocks

Abstract

As the scale of open pit mining and mining intensity have increased continuously over time, the stability of high and steep side slopes have become a key issue that must be addressed in open pit mines. A number of cases have shown that high and steep side slopes with bedded structures are highly susceptible to failure, and these failures may lead to significant damage and destruction. In this work, indoor modelling experiments were performed to study slip-buckling failures in high and steep side slopes set along the bedding plane of layered rocks. Here, experimental similarity criteria were derived according to similarity principles to produce an accurate match with the subject of this study and to select similarity constants. River sand, plaster, and barite were selected as equivalent materials in this experiment, and matching tests were performed. Fuzzy comprehensive evaluation was used to determine the optimal matching scheme on the basis of prototype similarity and physico-mechanical parameters including density, compressive strength, elastic modulus, and Poisson's ratio. The model was filled and constructed through layered filling and tamping, and observation points were installed throughout the model. Based on the subject selected for this study and dynamic excavation processes in mining simulations, we observed deformations of the model that occurred during excavation and the application of a load by a hydraulic servo loading system set on the top of the model. Through analyses of the results, it was found that rocks on the upper part of the slope slipped along the bedding, while slip-buckling failure occurred at the foot of the slope. Finally, the most dangerous slippage surface was identified as a composite surface with flat and arced surfaces.