Abstract: Rigid drainage piles combine the dual advantages of high bearing capacity and drainage performance. To investigate the anti-liquefaction effectiveness of rigid drainage piles in treating liquefiable subgrade, #7 silica sand was employed as the material for modeling the liquefiable subgrade. A shaking table model test was conducted to compare the performance of a drainage pile-net composite foundation with an ordinary pile-net composite foundation, utilizing a 3×5 pile group configuration and applying bidirectional dynamic loads both horizontally and vertically. The anti-liquefaction effect of the drainage pile-net composite foundation was analyzed based on dynamic responses, including excess pore water pressure, acceleration, and settlement. Experimental results indicate that the drainage pile-net composite foundation significantly outperforms the ordinary pile-net composite foundation. Specifically, the peak excess pore pressure ratio in the drainage pile condition ranges from 0.61 to 0.79, whereas it reaches 1.0 in the ordinary pile condition, indicating complete liquefaction. In the drainage pile condition, the horizontal peak acceleration amplification coefficient increases significantly from the bottom to the top of the embankment model, with a maximum amplification coefficient of 1.60. Conversely, in the ordinary pile condition, the peak acceleration amplification coefficient demonstrates a certain seismic damping effect in liquefied ground, reaching a maximum value of 1.07. The average settlement in the drainage pile condition is 11.4 mm, whereas it is 25.7 mm in the ordinary pile condition, representing a 55.6% reduction in the final settlement. These findings suggest that drainage piles effectively accelerate the dissipation of excess pore water pressure and reduce embankment settlement, making them an effective measure for treating liquefiable foundations.

Key words: rigid-drainage pile, pile-net composite foundation, liquefiable subgrade, shaking table test, excess pore water pressure, vertical settlement