Field Test and Numerical Simulation Study on Water Pressure Distribution and Lining Deformation Law in Water-Rich Tunnel Crossing Fault Zones

Abstract

This study investigates the water pressure distribution and deformation patterns in tunnel linings within water-rich tunnels traversing fault zones, focusing on the Gudou Mountain Tunnel. The study utilized field tests and numerical simulations to assess the water pressure distribution around test sections. Following the confirmation of consistent water pressure distribution patterns from field tests and simulations, we analyzed the deformation patterns of tunnel linings at various water levels. The results showed that water pressure is highest at the tunnel’s inverted arch and arch foot, moderately high at the vault and spandrel, and lowest at the arch waist. The sections RK51 + 590 and LK51 + 640, located on opposite sides of a fault crush zone, experience high fragmentation of surrounding rock. This allows rainfall and reservoir water to seep through fractures, causing increased water pressure and significant deformation at the inverted arch of these sections. With rising groundwater levels, deformation intensifies at the inverted arch, arch foot, and vault. The appearance of macro-cracks in these critical areas leads to groundwater seepage through the cracks, severely impacting tunnel operations. Consequently, reinforcing the inverted arch, arch foot, and vault is crucial to reduce the risk of water leakage in the tunnel.