Mechanical Responses of Slurry Shield Underpassing Existing Bridge Piles in Upper-Soft and Lower-Hard Composite Strata

With the development of urban metro systems, shield tunnels that pass through existing bridge pile foundations have become an inevitable engineering problem. Therefore, ensuring stability strata and piles during tunnel construction is a common goal in practice. Currently, research on mechanical responses under different conditions upper-soft lower-hard composite tunneling has not been conducted extensively. This paper presents numerical simulation passing foundation strata. Subsequently, surface subsidence single were analyzed evaluated. Additional stresses generated soil by selection grouting pressure considered to optimize driving slurry shield. Allowable values proposed evaluate disturbances caused excavation. The results show disturbance significantly influenced hard-rock height ratio, increases when ratio decreases. displacement internal force are load applied pile. study demonstrates changes boring, provides in-depth insights into deformation control underpassing structures