Model test of the stability degradation of a prestressed anchored rock slope system in a corrosive environmen

The long-term stability of a prestressed anchored slope might be influenced by the durability of the anchorage structure. To understand long-term stability of anchored rock slopes, the research presented herein evaluated the performance evolution of a prestressed anchored bedding slope system in a corrosive environment by model test. The corrosion process in a prestressed anchor bar was monitored in terms of its open-circuit potential (OCP), corrosion current density (CCD), and electrochemical impedance spectroscopy (EIS). The stability of the prestressed anchored slope was evaluated by monitoring changes in anchorage force and displacements. The experimental results show that prestress and oxygen could reduce the corrosion resistance of the anchor bar, and anchor bars in a chloride-rich environment are very susceptible to corrosion. Prestressed tendons in a corrosive environment suffer a loss of anchorage force, the prestress decreases rapidly after locking, and the rate thereof decreases until stabilising; in the later stage, corrosion leads to the reduction of the cross-sectional area of the steel bar which may cause the reduction in anchorage force again. Anchorage force controls the deformation and stability of the anchored slope, the prestress loss caused by later corrosion may lead to an increased rate of displacement and stability degradation of the prestressed anchored rock slope.