Prediction of continuous–discontinuous failure of granite subjected to direct shearing using acousto-optical-mechanical scheme

作者：Chunfeng Ye, Hengjun Chen, Cunbao Li, Fei Wu, Heping Xie · 发表于：Journal of Rock Mechanics and Geotechnical Engineering · 年份：2026 · DOI：10.1016/j.jrmge.2025.12.018 · 被引用次数：16 · 研究领域：Rock Mechanics and Modeling、Seismic Waves and Analysis、earthquake and tectonic studies

The catastrophic failure of deep rocks is difficult to predict, which generally exhibits a continuous–discontinuous behavior. A multimodal acoustic–optical–mechanical (AOM) monitoring system integrating acoustic emission (AE) analysis, digital image correlation (DIC), and mechanical loading was developed to address this limitation. Direct shear tests on granite were conducted under six different normal stresses to investigate the AOM responses during shear rupture. The shear failure was divided into three stages: Stage I—compaction and stable crack propagation, Stage II—from crack damage stress to catastrophic failure, and Stage III—post-peak residual shear and structural reconfiguration. The acoustic quiet period occurred consistently between Stages II and III, suggesting that the high heterogeneity induced by crack damage significantly disrupted the acoustic acceleration pattern preceding failure. This disruption explains the low predictive capacity of AE methods. An inverted U-curve was observed between the AE event rate and the loading time. An effective method was proposed for indirectly identifying crack damage stress. AE source classification and localization revealed that shear events were dominant (exceeding 74%), whereas tensile events were higher under higher normal stress, indicating a transition in microcrack evolution from shear-dominated to shear–tensile dominated mechanisms. The DIC-based principal strain fields showed local strain concentration near the nomin...