Abstract: To reveal the mechanical characteristics of rapid impact compaction treatment on pulverized soil foundations, an indoor triaxial test was conducted on compacted pulverized soil. This test simulated the effects of different tamping energies, determined the stress-strain behavior of pulverized soil under varying tamping energies and confining pressures, and calculated the mechanical parameters based on the Duncan-Chang model. The results showed that as tamping energy increases, the peak stress of the pulverized soil specimens also increases. Specifically, the peak strain of the pulverized soil foundation treated with 150 kJ of tamping energy could reach up to 396 kPa, which was 1.3 to 1.5 times greater than that of the foundation treated with 70 kJ. The shrinkage of the foundation after treatment at 150 kJ of tamping energy level was most pronounced in the impact tamping. Moreover, under the same tamping energy level, the peak stress of the pulverized soil specimens increased with the rise in confining pressure, with the peak stress corresponding to the strain of the specimen. For instance, at a confining pressure of 200 kPa, the peak stress of the soil treated with 150 kJ of tamping energy could reach 530 kPa, which was double that observed under the same treatment conditions at a confining pressure of 100 kPa. Using the Duncan-Chang calculation model, the mechanical parameters of the pulverized soil foundation after treatment with different tamping energies were calculated. These research findings provided theoretical support for the promotion and application of RIC technology.

Key words: rapid impact compaction, pulverized soil foundations, indoor large triaxial test, shear characteristics, Duncan-Chang model