Multifactor Analysis of Pore Water Pressure of Silt Soil Under Subway Load Based on Uniform Design

To elucidate the mechanisms of accumulated pore pressure in the soil surrounding subway tunnels and identify its influencing factors, this study selected the silt soil from Shanghai Metro Line 10 as the research object. A series of dynamic triaxial tests were conducted, employing a hybrid experimental design that integrated the controlled variable method with uniform experimental design principles. This approach enabled a systematic examination of the influence patterns of four primary parameters, including loading frequency, dynamic stress amplitude, consolidation ratio, and overconsolidation ratio (OCR) on pore water pressure. The experimental results revealed that under specific loading frequencies, pore water pressure exhibited a positive correlation with increases in dynamic stress amplitude, consolidation ratio, and OCR, while demonstrating an inverse relationship with loading frequency increases. A quantitative ranking of the factors’ influence on pore water pressure, based on their correlation strength, is as follows: dynamic stress amplitude, loading frequency, consolidation ratio, and OCR. Notably, dynamic stress amplitude exerts the most significant impact on pore water pressure, highlighting the need to prioritize the role of dynamic eccentric stress in subway engineering practices. Furthermore, the regression equation established by accounting for the coupled effects of multiple factors demonstrates a good fit, thereby providing valuable insights for subway tunnel design.