The dynamic hydraulic response and particle migration of subgrade structures under traffic loads are fundamental and critical to revealing the generation mechanism and evolutionary process 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 test results show that the slurry sloshing causes alternating positive and negative pressure gradients within the gravel layer. This oscillating pressure gradient enhances the pore seepage in the underlying sandy silt layer, providing the necessary hydrodynamic conditions for fine particle migration. The migration of fine particles increases the slurry turbidity until it reaches a steady state value. Upon the removal of dynamic loading, the fine particles in the slurry quickly settle and fill the gravel pores, forming an interlayer, which significantly reduces the vertical permeability of the gravel-sandy slit column. Based on the engineering practice of treating mud pumping on the G0615 Dema Expressway (Huashixia to Jiuzhi section) in Qinghai Province, it was found that an important inducement of mud pumping is the infiltration of rainfall and snowmelt water through the asphalt surface layer, and this water even formed "water pockets" within the subbase. The deformation of the pavement structural layers squeezes the slurry in the pores of the water-stable base layer upward through cracks when vehicles pass, causing continuous erosion and damage to the gravel materials. Considering construction difficulty, economic costs, and the ecological environmental protection requirements of the Qinghai-Tibet Plateau, different treatment methods such as grouting crack sealing and excavating milling sealing were adopted according to the severity and hazard 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 related 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.