Lining failure performance of highway tunnels induced by the drainage system deterioration

Abstract

Lining cracks and water leakage induced by tunnel drainage system deterioration occurred frequently, which have seriously influenced the durability of operation tunnels. In this paper, a series of model experiments and numerical simulations were performed to investigate the hydro-mechanical damage mechanism of the lining under the drainage system deterioration and groundwater height variation conditions. By combining model tests and numerical simulation, the seepage field distribution, the mechanical characteristics, and the failure evolution of the lining were conducted. Results reveal that the water pressure behind the tunnel lining increases as the drainage system deterioration, especially at the tunnel foot. The higher the groundwater height, the greater the water pressure increment with the blockage process. Furthermore, the internal force abruptly changes at the tunnel foot with the drainage system deterioration, and the maximum tensile stress on the lining foot outside reaches the damage strength of 2 MPa when the groundwater height exceeds 30 m, whereas the maximum compressive stress has not reached the compressive damage strength. Finally, micro-cracks under tension occur at the outside of the lining foot for the groundwater height of 30 m, and the lining foot is destroyed with the groundwater uplift to 40 m. In the case of tunnel drainage system deterioration, the high groundwater heights exceeding 30 m will affect the safety of the highway tunnel's foot.