Experimental investigation on chemical grouting in rough 2D fracture network with flowing water

This paper presents an experimental investigation of propagation and fluid pressure of grouting in a two-dimensional fractured network replica. Two-dimensional fracture network models with a rough profile were simulated based on Barton's standard roughness curves, and an orthogonal experiment of chemical grouting was conducted to explore the relationship between the sealing efficiency and different factors, including the joint roughness coefficient, initial water flow rate, gel time of slurry, and grout take rate. The results show that the initial water flow rate had the greatest influence on the sealing effect, followed by the joint roughness coefficient, grout take rate, and gel time of slurry. Together with the grouting quality and slurry diffusion form, the grouting sealings were divided into two types, i.e., partial plugging with edge unfilled and completely plugging with fracture fully filled. The slurry propagation sequence in the intersected fractures indicates that the slurry first diffuses downstream of the current fracture, then downstream of the cross fracture, and finally upstream of the cross fracture. The grouting pressure on the later stage of grouting was greater than that at the beginning of the grouting, resulting in a better grouting effect.