Advanced stability evaluation of underground marble quarry: a modelling and monitoring approach

This study evaluated the short-to-medium term static geomechanical stability of an underground marble quarry near Gujarat, India, using an integrated geomechanical approach combining FLAC۳D numerical modeling, real-time in-situ stress monitoring, and empirical methods. The room-and-pillar system in a high-strength marble rock mass (GSI=۷۲) intersected by a dolerite dyke was analyzed across varying overburden depths (۵۷–۸۷ m). Modeling confirmed pillar stability with stresses of ۴.۱۵–۶.۸۷ MPa and FOS consistently above ۲.۰. A ۲-m-thick roof layer showed localized yielding, effectively controlled by ۳.۵-m-long, fully grouted Fe۵۰۰D rockbolts (۲۴ mm diameter, ۲.۲ m×۲.۲ m spacing), achieving FOS of ۲.۲۷–۳.۹۳ (resin grout: ۳.۹۳). In-situ monitoring recorded stress variations of ۰.۲–۰.۴ MPa, validating predictions and enabling back-analysis that refined the deformation modulus to ۳۵ GPa for fractured marble. Monte Carlo simulations yielded a mean pillar FOS of ۲.۹۳ (۹۵% CI: [۲.۲۱, ۳.۷۶]), with only ۰.۶% probability of FOS<۲.۰. The validated framework confirms short-to-medium term static geomechanical stability consistent with DGMS safety requirements, supports adaptive staged excavations near the dyke, and provides a replicable model for sustainable underground dimensional stone quarrying in complex geological settings.

کلیدواژه ها:

Room-and-pillar mining ، dolerite dyke ، Rockbolts ، In-situ monitoring ، Monte Carlo simulation