Abstract: As a new grouting technology, pulsating grouting has been successfully applied to solve the problem of loose soil grouting. However, the dynamic response of slurry-soil coupling under pulsating load lags far behind the engineering practice. Based on the theory of pulsating grouting, a monitor system of pulsating grouting was designed. The response laws of sandy soil under different pulsating periodic loads were investigated by setting different pulsating periodic pressures and soil porosity ratios. Then through COMSOL Multiphysics platform and MATLAB, a program for simulating the stress-strain of slurry-soil coupling was developed. The applicability of numerical simulation was verified by comparing the existing grouting response theory with physical tests. The results show that when the pulsating pressure increases and the pore ratio of soil remains constant, the transfer rate of the pulsating stress borne by the skeleton force increases rapidly. The higher the pulsation frequency, the greater the soil stress. The fluctuating pressure will destroy the strong and weak force chain formed by the soil under constant load, resulting in the uniform stress transfer. The larger the pore ratio, the looser the soil and the higher the pulsation frequency, the more favorable the slurry migration in the soil. Compared with stable pressure grouting, pulsating grouting can lead to the stress concentration. Correspondingly, the slurry penetration and compaction caused by the stress concentration are beneficial to reduce the formation uplift displacement in the grouting process. Compared with stable pressure grouting, by which the grout is easy to split continuously along the small principal stress or formation defect, the grout diffusion induced by pulsating grouting is more controllable. In addition, the numerical simulation method provides a new idea for the slurry diffusion laws under different pulsating construction parameters, formation conditions and grouting materials. The research conclusions can provide a strong guiding significance for engineering practice.

Key words: pulsating grouting, sandy soil, dynamic response, clay-cement slurry, slurry-soil coupling