Numerical modelling technique for rock mass in underground coal mine by using grain-based model

Abstract

The stability of rock mass around longwall or excavation in underground coal mine is a prerequisite for the safe and continuous coal production. In practice, instability incidents commonly occur at longwall face or longwall roof that causes serious occupational injury or even death. Current research on the instability has not sufficiently interpreted the formation and propagation of rock mass failure, mostly due to the discontinuous, anisotropic, inhomogeneous and non-elastic nature of rock mass. To assist interpretation of the above stability behaviour, this paper presents a study to improve the numerical modelling technique of rock mass around longwall by using Grain-Based Model. The modelling technique uses Discrete Element Methods and the grain structure Voronoi. A procedure for calibrating rock properties in modelling technique is proposed and validated through application for field rock mass at Ha Lam coal mine, Quang Ninh province, Vietnam. The paper also presents a technique for selecting grain size and monitoring the modelling efficiently. The proposed procedure along with the modelling code are useful for investigation of rock mass around underground excavations from which technical solutions for safe and continuous production can be established.