Numerical Analysis on Fractured Roadway Stability Based on the FDM–DFN Coupling Method

Abstract

With the increasing complexity of mining conditions, the high degree of development of fractures in roadway surrounding rock significantly affects the stability of the rock mass in space, leading to difficulties in maintaining numerous roadways. In response to the challenges posed by the development of fractures in deeply buried roadway surrounding rock under complex geological conditions, a novel method for scientifically and reasonably characterizing the complex fractures in surrounding rock stability analysis of roadways was proposed, which combines field measurements, numerical simulations, and physical experiments, providing strong capabilities for comprehensive analysis. The development of fractures in coal mine sites was investigated and statistically analyzed using the scanning survey method, on the basis of which the probability density model of various fracture parameters was established by computational analysis. The Monte Carlo stochastic simulation technique was used to reconstruct and recover the fractures obtained from the field investigation using a discrete fracture network (DFN), which realizes the characterization of complex fractures in engineering field conditions. On this basis, and in conjunction with the finite difference method (FDM), the FDM–DFN coupling model was implemented into FLAC3D (version 5.01). A parametric study of the proposed FDM–DFN coupling model was carried out, and the results were compared to Mohr–Coulomb and strain-softening models. It has been shown that the fracture density, which is a newly considered parameter in the proposed model, exhibits noticeable effects on the deformation and failure of the roadway rock mass. Thus, the FDM–DFN coupling model offers a more realistic simulation of the roadway behavior than Mohr–Coulomb and strain softening models. The proposed model can be utilized for other applications involving rock reinforcement of mine openings under similar geotechnical conditions.