Influence of rising groundwater levels on the mechanical and deformation characteristics of bridge pile foundations in land subsidence areas

Long-term groundwater overexploitation has induced severe land subsidence in the Beijing–Tianjin–Hebei region, while groundwater level rise associated with the South-to-North Water Diversion Project and increased precipitation under climate warming have promoted groundwater level recovery. Rising groundwater levels may alter the hydro-mechanical behavior of thick soft soil and affect the safety of bridge pile foundations in subsidence areas. Taking the bridge pile foundation of the Xiong’an–Daxing rail transit project as an example, this study uses the finite difference method to investigate pile–soil stress and deformation responses under groundwater level rise. A moisture-content-dependent Burgers creep model is established to characterize soil creep and pile–soil interaction. The effects of groundwater level rise induced by groundwater recharge and rainfall on pile foundation deformation, bearing capacity, pore water pressure, and soil settlement are analyzed. The results show that the proposed model captures the staged evolution of soil settlement and that pile bearing capacity responds nonlinearly to groundwater level rise. The findings provide a reference for evaluating the safety of bridge pile foundations and related infrastructure under groundwater level recovery in land subsidence areas.