Simplified Analysis and Stability Evaluation of Excavation Loose Zone of Interbedded Soft and Hard Rock Slope Based on Model Test

Based on the results of model test and the definition of excavation loose zone, the scope of excavation loose zone of soft and hard rock interbedded slope is determined, and a simplified mechanical model is established. Based on the Mohr-Coulomb criterion, the calculation formula of the stability coefficient is obtained. When the stability coefficient is equal to the critical value 1, the range of the potential failure area of the slope is discussed, and the stability evaluation and instability mode of the slope are studied. The model test and simplified analysis of the loose zone show that the dangerous sliding surface of the slope with interbedded soft and hard rock occurs in the deep soft rock stratum. When the excavation happened to the deep soft stratum, a large range of disturbances will occur, cracks will be generated, and the channel of water supply will be provided to reduce the stability coefficient of the loose zone, leading to the instability of the slope.