Research on Application of High-Pressure Cyclic Grouting Technology in Soft Soil Layers

Aiming at technical challenges such as the insufficient bearing capacity of orifice formation leading to slurry overflow and non-uniform formation reinforcement in soft soil layer grouting engineering, an external cyclic grouting process through the grouting pipe is innovatively proposed. Distinguished from traditional in-hole circulation methods, this process achieves bottom-up cyclic grouting through a slurry return channel outside the grouting hole, which effectively reduces the risk of orifice fracturing and improves grouting uniformity. A grouting pressure loss equation is established to quantitatively analyze the relationships between the allowable grouting pressure and the side wall opening of the grouting pipe, slurry rheological parameters, surface consolidation depth, and surface consolidation strength. It is revealed that slurry with high viscosity and low yield stress is suitable for deep grouting, and a design criterion innovatively proposes that the side wall opening of the grouting hole should dynamically increase with the grouting depth. Based on the strain–pressure curve, a prediction model for the reinforcement radius of compaction grouting is established. Slurry rheological parameters and formation mechanical parameters are obtained through laboratory tests, and field grouting tests are conducted. The reinforcement effect is verified by means of ground-penetrating radar and standard penetration tests. The results show that, compared with traditional grouting processes, this process significantly improves the bearing capacity of the orifice and enhances the uniformity and compactness of formation reinforcement and that the theoretical prediction error of the reinforcement radius is less than 15%. The research results provide the theoretical basis and technical support for soft soil grouting engineering and have important engineering application value.