Numerical investigation of spatiotemporal flowing and blocking characteristics for grouting in multi karst conduits

Abstract

Grouting in flowing water for multi karst conduits is commonly used in water hazard control, yet there is no quantitative guidance. We utilized numerical simulation methods to simulate and analyze the entire process of multi-conduit flowing water grouting. First, based on the grouting simulation method proposed earlier, we constructed mathematical models for grouting in flowing water and extended it to the simulation of karst multi-conduit flowing water grouting which was validated through comparative indoor experiments. Second, we conducted variable control experiments to study and analyze the effects of branch diameter, quantity, and morphology on flow rate, pressure, and slurry diffusion patterns, thus revealing the mechanism of slurry diffusion and conduit blocking in karst multi-conduits. Finally, research results were applied to the water control of a limestone mine in Pingnan, Guangxi. It's found that 1) the straight branch connected to the main conduit are advantageous; 2) the shorter the branches, the greater total volume of slurry passing through; 3) with other conditions constant, the larger branch diameters, the higher flow rates, the lower slurry retention rates, and the greater difficulty in conduit blockage; 4) Blockages typically start from the bottom of the conduit and gradually progress upwards, with plugging firstly occurring at the grouting hole. This study is expected to provide theoretical guidance for the construction of multi-conduit flowing water grouting in karst areas.