Abstract: In order to improve the longitudinal stiffness of the shield tunnel and prevent the track from disengaging when the shield tunnel has uneven settlement, a new type of shield tunnel and track slab composite structure is proposed, in which the track slab is in the form of U-shaped groove. Through the numerical simulation analysis of the new superimposed tunnel structure, the numerical simulation analysis is compared with the circular shield tunnel. The results show that the new composite structure greatly improves the longitudinal stiffness and lateral stiffness of the shield tunnel. Through the inversion calculation and analysis of the numerical simulation results of the new superimposed tunnel, it is found that the longitudinal stiffness of the new superimposed tunnel is increased by 182.72%. The composite structure of the new U-shaped groove track slab and the shield tunnel improves the longitudinal and lateral stiffness of the shield tunnel without increasing the clearance of the shield tunnel, and the upper webs on both sides of the U-shaped groove track slab form two longitudinal evacuation channels. The new structure is worthy of popularization and application.