###### 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 \(\text{LK51}+640\), 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. Water-rich tunnel; water pressure distribution; lining deformation; field test; numerical simulation 20242  
rise excessively. [PERSON] et al. [9] conducted a seepage test to address the imbalance between the recharge and discharge of groundwater around tunnels under heavy rainfall conditions. The spatial distribution characteristics of the seepage field in variable water level tunnels indicate that the grouting cycle exacerbates the uneven distribution of water pressure behind the lining. [PERSON] et al. [10] treated the tunnel grouting ring and lining structure as a single entity. They proposed a spatial distribution formula for pore water pressure around tunnels based on [PERSON]'s classic analytical solution. Field experiment data indicate that tunnels equipped with both grouting rings and linings better align with theoretically derived water pressure results compared to tunnels without linings. [PERSON] et al. [11] analyzed the influence of tunnel construction phases on ground settlement through field tests. They identified fluctuations in tunnel pore water pressure as the primary cause of sand layer settlement. Based on an analysis of tunnel excavation parameters, they evaluated the effectiveness of on-site grouting reinforcement in the sandy soil layer. [PERSON] et al. [12] compared the analytical solution of tunnel seepage field distribution characteristics with field measurements of precipitation and groundwater distribution. They demonstrated that increased precipitation depth and aquifer thickness lead to a significant rise in pore water pressure, confirming the accuracy of the numerical analytical solution. [PERSON] et al. [13] discovered that an increase in the permeability coefficient of the grouting ring results in higher water pressure behind the tunnel lining structure. Additionally, using a grouting ring with a lower permeability coefficient in water-rich tunnels can effectively reduce the impact of groundwater seepage on the lining structure. [PERSON] et al. [14] investigated the influence of grouting slurry parameters and geotechnical parameters on the lining structure of shield tunnels through field tests. The results indicated that the setting rate of the grouting slurry is negatively correlated with the uplift of the tunnel lining, whereas the elastic modulus of the geotechnical body is positively correlated with the uplift of the tunnel lining. The above studies indicate that conducting field tests can effectively and accurately identify the distribution characteristics of the tunnel seepage field. However, the impact of high water pressure around tunnels in water-rich areas on the lining structure remains a major concern.