Modelling surface subsidence of coal mines using a bonded block numerical method

Abstract

Surface subsidence is common geologic hazard in coal mines when longwall mining method is applied. In this research, a Bonded Block Model (BBM) is selected to numerically simulate and analyze the surface subsidence of coal mines. Parametric study is conducted and key factors controlling the subsidence are characterized. BBM models with no bedding planes realistically simulate the maximum subsidence, but overestimate the subsidence levels above the panel edges. The bedding planes introduced in the BBM models potentially provide more realistic subsidence profile. The separation of the planes and downward bending of the layered strata, as commonly observed in coal mines, are simulated and captured. In addition, high horizontal stress plays a key role in simulating more realistic subsidence profiles. The methodologies and conclusions of this research are expected to improve our understandings of the surface subsidence of coal mines and provide reliable tools to analyze and characterize this challenging issue.

Keywords

• Surface subsidence
• Bonded Block Model
• parametric study
• bedding planes
• longwall mining