The Role of Heterogeneity on Deformation and Flow in Fractured Coal Slopes

Abstract

The fractures in brown coal influence fluid flow and deformation in these materials. These fractures display highly heterogeneous characteristics in the distributions of their apertures, separations and orientations. While discrete fracture models have previously been used to analyse the effects of fractures, such models are not feasible for the scales encountered in many brown-coal mines. Instead, here a continuum permeability model is used to capture the effects of the fracture heterogeneity on fractured coal. This paper presents an analysis of the fracture heterogeneity of brown coal at the AGL Loy Yang coal mine in Latrobe Valley and its influence on the fluid flow, dispersion and rock stability. A stress dependent fracture permeability is considered and captures the effects of heterogeneity in the fracture aperture and orientation. Numerical simulations conducted with multiple plasticity models present different flow paths and potential failure modes depending on the the implemented boundary conditions.

Keywords

• fractures
• hydraulic properties
• numerical modelling
• fracture strength