Experimental assessment of structural responses of tunnels under the groundwater level fluctuation

Abstract

Groundwater is one of the important factors affecting the stability of underground structures. However, the researches on the tunnel responses under the change of groundwater level based on the experiments are still insufficient. In this study, the interaction between underground tunnels and soil during the change of groundwater level in sand and clay stratums was investigated through the model experiments. Adopting the self-designed experimental equipment and innovative experimental methods, the contact pressure, bending moment, pore water pressure, buoyancy, and vertical displacement of two types of tunnels throughout the testing process were monitored. The impact of time lag effect on tunnels was also discussed. Force analysis indicates possible critical locations of both tunnels along the whole groundwater change process. The groundwater buoyancy in clay was reduced by time lag effect. The structures showed periodic sinking and floating behavior, and substantial settlement occurred with the decline of water level in the final stage.