Arching effect in slopes under excavation: Classification and features

Classifying excavation-induced slopes considering the arching effect and understating the features are crucial for determining the appropriate designs for excavation, assessing the long-term behaviors of excavations, and identifying potential failure modes. The objective of this study is to establish a classification system for excavation-induced slopes and to identify the features and applications of each slope. A series of physical model tests were carried out to investigate the deformation and failure behaviors of slope under different conditions. Assisted with the monitoring of earth pressure cells, digital and high-speed cameras, the deformation and failure characteristics were analyzed through particle image velocimetry (PIV) analysis. The results show that the slope models can be separated into three types: "shear plane arching" slope; "partial arching" slope; and approaching "full arching" slope. During the prefailure process, unyield zone ratio decreases from "shear plane arching" slope to "particle arching" slope to approaching "full arching" slope, while the yield zone ratio and interaction zone ratio increase. In the postfailure, the "full arching" slope can create higher initial kinetic energy. The classification and features of the excavation-induced slopes helps to supply engineers with the information for guiding the operation at sites.