152 / 2024-03-05 17:38:31

Unsteady-state permeation diffusion mechanism of Bingham grout in high confining pressure saturated porous media

Permeation grouting; Unsteady-state; Confined pressure saturated porous media; Grout diffusion

The permeation grouting technology has found widespread application in engineering practice. The stress state, pore water pressure of the injected medium, and grouting parameters such as grouting pressure, grouting rate, and grout flow pattern play significant roles in the infiltration and diffusion of the grout. In this study, to address the limitations of traditional infiltration models that assume constant grouting pressure and rate over a certain period, an unsteady-state permeation diffusion model for Bingham grout in highly confining pressure saturated porous media was developed based on the two-phase flow theory and Bingham fluid rheological equation. Numerical solutions using the Finite Volume Method (FVM), analytical solutions under simplified conditions, and quasi-steady-state solutions are provided. Through grouting case studies, comparisons were made between the numerical and analytical solutions of unsteady-state permeation diffusion, quasi-steady-state solutions, and traditional steady-state solutions. The research findings indicate that the unsteady-state permeation model, which considers the actual flow pattern of the grout, is more suitable for describing the diffusion behavior of the grout in highly confining pressure saturated porous media compared to traditional steady-state analysis. Furthermore, the accuracy of quasi-steady-state analysis lies between the two aforementioned methods. These findings offer a more effective and accurate understanding of the permeation and diffusion behavior of grout in highly confining pressure saturated porous media, which can inform practical design and construction endeavors.