A methodology to investigate fluid flow in sheared rock fractures exposed to dynamic normal load

Understanding the flow characteristics in sheared rock fractures is with significance for many engineering projects (e.g., geothermal reservoirs, dams, oil or gas explorations, etc.). This study reports a FLAC3D FEM-based fluent CFD - methodology to investigate the fluid flow patterns in sheared rock joints exposed to complex stress states. First, a direct shear experiment of a rough basalt fracture, subjected to dynamic normal force is performed. A FLAC3D numerical model is setup to simulate the experimental process. Using a self-designed algorithm, the fracture contact area, aperture size, and fracture volume are analyzed at different shear displacements in the numerical model. The two-dimensional apertures, obtained from the FLAC3D model, are applied to FEM-based fluent CFD to analyze variation patterns of the relevant fluid flow during the shear process. Results show that the flow characteristics including the generation and development of eddy currents, and the estimated value of the Reynolds number, flow rate, and apparent permeability, are associated with both the shearing and the dynamic normal force. These findings provide a new horizon on features of aperture flow in rock mass under complex geological stresses.

Automated summary

This study utilized FLAC3D and FEM-based fluent CFD methods to investigate fluid flow characteristics in rock fractures, revealing that flow characteristics are closely related to both shearing and dynamic normal force.