## 5 Conclusions and Prospects  
Based on field test and numerical simulation, this paper investigates the water pressure distribution and lining deformation in a water-rich tunnel through a fault zone. The main conclusions are as follows:  
(1) Overall, the greatest water pressure occurs at the inverted arch and arch foot, followed by the vault and spandrel, with the least pressure at the arch waist. Due to the RK51 + 590 and LK51 + 640 sections being located on either side of a fault crush zone with highly fractured surrounding rock, atmospheric precipitation and reservoir storage collect through rock fractures to these sections, resulting in higher water pressures at these locations.  
(2) In the rainy season, increased rainfall activates fissures as seepage channels, elevating groundwater levels and subsequently increasing water pressure behind the lining. This results in significant deformation, particularly at the inverted arch positions of sections LK51 + 640 and RK51 + 590, where pressure is highest. The tunnel vault, subjected to heavy load and tensile stress from the surrounding rock, also shows substantial deformation, as does the arch foot, which experiences concentrated stress and larger plastic deformations than the vault.  
(3) As groundwater levels rise, the deformation of the inverted arch, arch foot, and vault increases. The emergence of macro-cracks in these areas allows groundwater to seep into the tunnel, jeopardizing its operation. During the rainy season, reinforcing these areas is crucial to prevent water seepage and ensure structural integrity.  
There are still certain limitations in this study. Currently, engineering recommendations to reduce the risk of tunnel leakage are proposed based only on the deformation characteristics of the lining structure. Future research will focus on the bending moments and axial forces on the tunnel lining structure to calculate the safety factor of the lining structure. Furthermore, FLAC\({}^{\text{3D}}\) does not consider the discontinuities between rock joints and blocks, whereas the 3 DEC 7.0 discrete element software can simulate discrete systems like rock masses and fracture media. In the future, FLAC\({}^{\text{3D}}\) can be coupled with 3 DEC to achieve accurate analysis of the seepage field characteristics around tunnels under complex geological conditions, such as fault fracture zones.  
Conceptualization, Z.F. and D.L.; methodology, Z.F. and D.L.; software, D.L. and S.W.; validation, D.L. and L.Z.; formal analysis, D.L. and L.Z.; investigation, F.W.; resources, Z.F.; data curation, D.L. and S.W.; writing--original draft preparation, D.L.; writing--review and editing, D.L. and L.Z.; supervision, Z.F. and F.W. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: Data are available in a publicly accessible repository.  
The authors extend their profound gratitude to [PERSON] and [PERSON] of Poly Changda Engineering Co., Ltd. in China. Their magnanimous provision of both funding and the test site was instrumental in the successful execution of the experiments detailed in this study.  
The authors declare that this study received funding from Poly Changda Engineering Co., Ltd. in China. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.