The dissolution process induced by reactive fluid flow in rock fractures significantly impacts geotechnical engineering safety

while the dissolution mechanisms of inclined fractures under gravitational effects induced by solution density differences remain unclear. This study systematically investigates the dissolution patterns and permeability evolution of fractures with different inclinations through pore-scale numerical simulations and visualization experiments. Results indicate that buoyancy-driven convection caused by solution density differences generates “vortex-like” flow structures during inclined fracture dissolution

where buoyancy convection along the fracture length dominates channel development

whereas gravitational effects in the vertical direction can be negligible. A criterion for the transition of dissolution patterns was established using the Richardson number (): When > 10 (buoyancy-dominated regime)

increased inclination promotes wormhole growth and reduces the required injection volume for breakthrough; when ≤ 10 (forced convection-dominated regime)

dissolution patterns are governed by injection velocity

manifesting as compact dissolution

wormhole dissolution

or uniform dissolution. A theoretical model for optimal injection velocity incorporating gravitational effects was developed

enabling accurate predictions across varying inclinations. This research provides a theoretical guidance for seepage control in underground engineering within soluble rock formations and offers critical insights for safety assessments in CO geological storage

in-situ leaching mining

and related applications.