Lateral Pressure Effects on Adjacent Bridge Piles in Deep Soft Foundations Based on a Soil-Squeezing Model

Lateral pressure generated by pile penetration in deep soft-soil foundations can compromise the bearing performance of adjacent cast-in-place bridge piles. This study, conducted on a highway-widening project, systematically investigated soil-squeezing-induced lateral compression during pile driving and its influence on adjacent bridge piles. A physically based theoretical model was developed to predict soil displacement induced by the soil-squeezing effect. An empirical power-law expression reproduced the theoretical predictions with high accuracy when the clear spacing between a bridge pile and a driven pile exceeded one driven-pile diameter. An attenuation model for lateral pile pressure, which assumes the same decay rate as the displacement field, was also proposed. The field results show that pile movements are confined mainly to the soft-soil stratum and that pile–soil interface pressure occurs almost exclusively during penetration, dissipating shortly thereafter. The model further reveals that bridge piles undergo larger lateral deformations than prestressed high-strength concrete pipe piles under equal lateral stress because of their greater diameter. The proposed method provides a practical means to assess the loss of bearing capacity and safety of bridge piles subjected to soil-squeezing effects. Measures such as optimizing the pile-driving orientation or implementing predrilling can mitigate adverse impacts.