The dynamic hydraulic response and particle migration of subgrade structures under traffic loads are fundamental to reveal the formation and development mechanisms of mud pumping.The driving mechanism of fine particle migration in the mud pumping state was explored by conducting laboratory tests on layered gravel-sandy silt columns under dynamic loads.The results show that the slurry sloshing causes alternating positive and negative pressure gradients within the gravel layer.This oscillating pressure gradient enhances the pore permeability in the underlying sandy silt layer,providing the necessary hydrodynamic conditions for fine particle migration.Fine particle migration increases the slurry turbidity to a stable value.Upon the removal of dynamic slurry loading,the fine particles quickly settle and fill the gravel pores,forming a muddy interlayer,which significantly reduces the vertical permeability of the gravel-sandy slit column.Based on the engineering practice of treating mud pumping on the G 0615 Dema Expressway (Huashixia to Jiuzhi Section ) in Qinghai Province,it was found that an important driv er for mud pumping formation is the infiltration of rainfall and snowmelt water through the asphalt surface layer,and this water can even form “water pockets ” within the subbase.When vehicles pass,the deformation of the pavement structural layers causes the slurry in the pores of the water-stable base layer to be squeezed upward through cracks,leading to continuous erosion and damage to the gravel materials.By considering construction difficulty,economic costs,and the ecological environmental protection requirements of the Qinghai?Xizang Plateau,different treatment methods such as grouting repair and sealing,as well as milling and sealing were adopted,respectively based on the severity and level of the hazard.These methods have played a positive role in sealing and reinforcing the water-stable base layer and reducing pavement permeability.The research provides valuable insights for understanding the development patterns of mud pumping,effectively enhancing the treatment capabilities and promoting high-quality maintenance of plateau highways.