English：

To address the impact of structural deformation in the short subgrade transition section betweenbridges and tunnels on traffic safety and operational efficiency, it is necessary to take deformation controlmeasures for this section. Existing deformation control technologies face the issues such as high costsassociated with high-strength materials and the need to further improve the accuracy and reliability ofnumerical simulation and experimental research. Therefore, a deformation control method for bridge-tunnel short subgrade transition section structure under mapping relationship is designed. By utilizingnumerical simulation method to simulate the settlement of bridges under different vehicle loads and naturalenvironmental factors, the degree and trend of foundation settlement can be accurately predicted,facilitating settlement prediction. Considering the mapping relationship between bridge settlement andstructural deformation in the short subgrade transition section between bridges and tunnels, the verticaldeformation values of this section can be predicted, ensuring a smooth transition between the bridge andsubgrade, and reducing the adverse effects of settlement differences. Based on the calculation results, thedeformation modulus of the subgrade bottom layer in the transition section is determined, enhancing theoverall performance of the transition section. This involves completing the parameter design for variousfillers in the subgrade bottom layer, calculating the design thickness of each filler, and designing thethickness of the surface layer of the subgrade in the transition section. Test results show that the relativesettlement deformation of short subgrade transition sections 1, 2, and 3 is relatively small, and thedifference between their relative settlement deformation after one month and six months is minimal.