Effects of excavation geometry in energy evolution in underground mines

With mines reaching into greater depth, problems with violent failures become more prevalent, such as rockbursts. To assess the potential for such occurrences, understanding energy dynamics is crucial. This study delves into the impact of excavation shape, aspect ratios, inclined angles and in-situ stress on dissipated plastic energy and released kinetic energy through numerical simulations. Detailed analyses of plastic zone around rectangular and elliptical excavations, varying in aspect ratios, unveiled the distinct patterns of tensile and shear plastic zone. Quantitative assessments of dissipated plastic energy and released kinetic energy highlighted contrasting behaviors between rectangular and elliptical excavations across various aspect ratios. Although the relationships between these energies and excavation parameters are found to be intricate, it becomes evident that: with an increase in the aspect ratio, both shear and tensile plastic zones exhibit a growing trend, and their distribution shows a high degree of consistency with regions of energy concentration. When the aspect ratio is below 1.5, elliptical excavations release slightly less kinetic energy than rectangular ones. Beyond 1.5, this relationship reverses. Moreover, upon exploring inclined angles, critical angles were identified, delineating points where the influence of aspect ratio nearly diminishes. Under the given in-situ stress conditions, approximately 50° and 20° serve as the critical angles for dissipated plastic energy and released kinetic energy, respectively. Changes in the degree of in-situ stress anisotropy have a limited impact on the overall energy trends but significantly alter the critical values of aspect ratio and inclination angle. When the in-situ stress ratio matches the excavation aspect ratio, both forms of energy reach their minimum values. These findings illuminate the complex interplay between excavation geometry and energy dissipation, offering invaluable insights for designing effective excavations and devising strategies to mitigate failures. • Excavation geometry significantly impacts energy evolution, affecting failure patterns in deep mining operations. • Numerical simulations reveal optimal aspect ratios and inclination angles to minimize failure risks. • The degree of in-situ stress anisotropy affects the dissipation and release of different forms of energy. • Findings provide insights for safer underground excavation designs by analyzing dissipated plastic and released kinetic energy.