Experimental Study on the Diffusion Law of Horizontal Grouting in Shallow Sand Gravel Layer

Common problems in horizontal grouting engineering projects that it is difficult to evaluate the grouting slurry diffusion range due to theoretical limitations. Here we report a novel experimental design that investigates the influence of grouting parameters (grouting time, pressure, slurry water-cement ratio) and permeability coefficient on grouting slurry diffusion in order to determine the diffusion law of horizontal grouting in shallow sand gravel layer. The results indicate that grouting pressure is sensitive to the most significant impact on the slurry diffusion radius, and the following rank is grouting time > slurry water-cement ratio > permeability coefficient of the stratum. Next, discrete element software was employed for single-factor analysis. Finally, a numerical model of shield tunnel settlement was developed to evaluate the impact of grouting reinforcement on ground settlement. The findings reveal that the slurry diffusion exhibits a non-standard columnar shape with horizontal symmetry, while the permeability coefficient of the sand and gravel influences vertical diffusion.