Effect of excavation shape in underground mines on ventilation and stability analysis
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Date
2025
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Publisher
National Higher School of Technology and Engineering -Annaba
Abstract
Mining safety is a complex challenge due to the many parameters influencing the security function. Among these, underbreak and overbreak in excavations are major concerns. While technical literature addresses the mechanisms behind under/overbreak in underground environments, it remains limited when it comes to their practical consequences. To evaluate the sensitivity of geotechnical analysis to excavation shape, six profiles were studied: three idealized (circular, segmental, and rectangular) and three visually approximated ones. Numerical modeling revealed significant differences in stress values, distribution, and magnitude, leading to variations in safety factors and the radius of plastic zones. Relying solely on idealized shapes may mislead the design process and compromise safety. For ventilation analysis, a simplified model of the mine was created. The Hardy Cross method was applied to both the real and theoretical excavation shapes. The excavation profile impacts resistance values, airflow distribution, and velocity. Idealized profiles can overestimate airflow by more than 30% in some cases, mainly due to neglecting wall roughness.
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Keywords
Sécurité minière, profil dexcavation, sous-creusement/surcreusement, modélisation géotechnique, distribution des contraintes, ventilation, méthode de Hardy Cross, débit dair, rugosité des parois