Abstract: Based on the chemical reaction principles of slurry, a two-dimensional simulation method for polymer fracture grouting in soil was developed using the extended finite element method (XFEM), the modified Cam-clay model, and the calculation model for polymer slurry expansion force. The serviceability of this method was confirmed. The study then examined the temporal changes in slurry expansion force, slurry vein morphology, and soil void ratio, while also exploring the influence of grouting hole depth and soil fracture toughness on the expansion process of slurry veins. The results indicate that the expansion force of the slurry increases initially due to the chemical reaction process of polymers, peaks, and then rapidly decreases to stabilize under the interaction of slurry and soil. The development rates of vein length and width are asynchronous: the vein length remains relatively constant while the width linearly increases from crack initiation to the second expansion stage. Subsequent to the second crack expansion, the vein length linearly increases, and the width growth rate tends to slow down. The slurry squeezing effect significantly reduces the soil void ratio in a specific range on both sides of the crack. Perpendicular to the crack surface, the void ratio decreases closer to the center of the grouting hole. Over time, the void ratio decreases. As the crack expands and the expansion pressure decreases later on, the soil’s void ratio on both sides of the crack surface partially recovers and then stabilizes. With increasing grouting hole depth and fracture toughness, the slurry vein length gradually decreases while the width continuously increases, with the change rate of the two remaining relatively constant. The stability time of slurry vein expansion advances with increasing burial depth and delays with increasing fracture toughness.

Key words: polymer fracture grouting, simulation method, chemical reactions, expansion force model, extended finite element method, modified Cam clay model