Investigation on Rectangular Tunnel Mechanical Response Under Groundwater Level Fluctuation Based on Model Test and Numerical Simulation

Groundwater is a critical determinant significantly affecting the stability of underground tunnels. Despite its importance, research remains limited on the influence of groundwater level fluctuations on the behavior of rectangular tunnels. This paper addresses this knowledge gap by thoroughly examining the response mechanism of rectangular tunnels subjected to groundwater level fluctuations, utilizing a combination of scale model tests and numerical simulations. The study emphasizes the analysis of the effects of varying buried depth ratios and speeds of groundwater level fluctuations on the performance of rectangular tunnels. Findings indicate that changes in groundwater levels result in the vertical displacement of the tunnel and instigate deformations in the surrounding soil. Moreover, alterations in hydraulic conditions considerably shift the stress and strain distribution within the tunnel, with stress concentration becoming increasingly evident as the tunnel's buried depth ratio and the speed of groundwater level fluctuations increase. The insights derived from this study offer valuable contributions for future research efforts and engineering design in the domain of rectangular tunnel stability under fluctuating groundwater conditions.