Large area construction squeezing effect of PST piles in deep soft soil sites based on CPTU testing

To analyze the soil squeezing effect during the large-scale construction process of PST pipe piles, the multifunctional high-precision pore pressure static penetration test (CPTU) technology was used to test the side wall friction resistance, excess pore water pressure, and dissipation process of the soft soil layer before, during, and after the construction of PST piles. The test results show that in the same layer of silt, the horizontal consolidation coefficient decreases continuously with depth, and the squeezing effect itself also intensifies the decrease in the consolidation coefficient of soft soil. When the pipe piles are longer, the time required to alleviate the squeezing effect is longer; The influence of pile group construction organization on the control of the soil compaction effect is significant, and the pore water pressure increment caused by construction away from the measuring point is only 29% of that caused by construction towards the measuring point; After the construction of PST piles, the strength of the soft soil on the site was reduced by disturbance, with a reduction of up to 40%. After about 120 days, the soil strength of the soft soil layer can recover to the level before construction. For shallow soft soil adjacent to the upper permeable layer, dynamic consolidation occurs after pile driving, and the long-term strength has improved compared to before construction.