DIFFUSION MECHANISM OF PULSATING GROUTING IN COMPLETELY WEATHERED ALTERED GRANITE CONSIDERING INFILTRATION EFFECT

Although pulsating grouting has been used as a process for anti-seepage reinforcement treatment of loose strata, the diffusion law of slurry under pulsating pressure is still unclear. Based on the theoretical model of pulsating grouting, the slurry transport equation considering the percolation effect is derived. The numerical simulation program of pulsating grout diffusion considering the percolation effect is obtained by relying on COMSOL Multiphysics platform and Richards equation, combined with MATLAB secondary development. The pulsating and steady pressure grouting simulation device is self-designed to compare the slurry diffusion percolation of pulsating grouting and steady pressure grouting. The process of pulsating grouting on the formation mutual coupling is calculated by using the numerical simulation to construct the pulsating cycle pressure variation model. Through the mutual verification of the above methods, the diffusion law of Bingham fluid in sandy soil under the control of pulsating grouting pressure is revealed by considering the percolation effect. The results show that in sandy soils, steady pressure grouting is easy to split and form slurry veins, diffuse percolation siltation and uncontrollable slurry diffusion. The diffusion of slurry under pulsating pressure control can form an effective reinforcement circle and slurry bubble with wide percolation range. The trends of slurry diffusions obtained from theoretical calculation, indoor test and numerical simulation are consistent. The slurry diffusion measured by the test and the slurry diffusion calculated by theoretical and numerical simulation verify that the slurry diffusion under pulsation pressure control is more controllable and can form a more uniform diffusion range. The research results can provide strong guidance for pulsating grouting anti-seepage reinforcement, numerical simulation and engineering practice.