Progressive Damage Evolution in Rocks Subjected to Post-peak Cyclic Loading History

What is it about?

Rock materials in civil and mining projects are usually subjected to different cyclic loading histories at different stress levels because of rock-breakage operation, mechanical excavation, haulage vibrations, etc. Under cyclic loading conditions, rocks may exhibit an overall complex nonlinear stress-strain response at the failure stage, which is completely different from that under static to quasistatic loading conditions. This, in turn, may degrade the mechanical properties and aggravate the long-term instability of structures. Therefore, an investigation of damage evolution and the failure behavior of rocks under cyclic loading is of relevance. In this regard, insights into the complete stress-strain response of rocks (i.e., the pre-peak and post-peak regimes) obtained experimentally are critical in rock engineering to study energy evolution and failure mechanisms.

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Photo by Taton Moïse on Unsplash

Photo by Taton Moïse on Unsplash

Why is it important?

In rock engineering applications (e.g., mining pillars around galleries in deep underground excavations and bridge columns), rocks may reach their peak strength under monotonic loading conditions and then experience cyclic loading induced by different seismic sources in the post-peak regime. Therefore, it is critical to investigate the failure response of rocks subjected to cyclic loading in terms of long-term stability assessment. Because of difficulties in capturing the complete pre-peak and post-peak behavior of rocks under cyclic loading, especially the brittle rocks that show self-sustaining behavior in the post-peak regime, the post-peak stress-strain cyclic response of rocks has not yet been fully explained. In this study, an innovative testing method is presented to capture the failure behavior of rocks under post-peak cyclic loading.