## 1 Introduction  
When tunneling in weak or fractured rock masses, maintaining the stability of the tunnel surrounding rock presents significant challenges [1, 2]. Numerous scholars, based on field engineering practices, have conducted research through theoretical analysis, numerical simulation, and other approaches [3]. [PERSON] [4] introduced the New Austrian Tunneling Method (NATM), emphasizing the importance of controlling tunnel deformation by enhancing the stiffness of the pre-excavated rock mass, thereby ensuring tunnel safety. [PERSON], [PERSON] and others [5], based on a large-scale fault zone tunnel project, designed a variable-stiffness lining structure for fault-crossing tunnels using the seismic design concepts of \"attract\" and \"let go\". This design aims to induce structural deformation and reduce the range of earthquake damage. Theyalso conducted shaking table tests on the variable-stiffness lining of fault-crossing tunnels for validation. [PERSON], [PERSON] and others [6] analyzed the risk assessment reports of railway tunnel projects to identify the safety risk factors in fault fracture zone tunnel construction. They extracted the causal logic between these safety risk factors and constructed a safety risk transmission network. [PERSON], [PERSON] and [PERSON] [7] conducted a classification study on fault beccias, analyzed their impact on tunnel construction, and provided valuable insights for tunnel design. [PERSON], [PERSON] and others [8], based on silo theory and the stress distribution characteristics of strata, considered the geometric features of fault fracture zones and surrounding rock properties. They established a simplified calculation model for vertical loads in tunnels within fault fracture zones and solved it using stress transfer principles. [PERSON], [PERSON] and others [9], to explore tunnel construction through fault fracture zones, considered the example of different fault morphologies at the Wulipo Tunnel on the Mianjiu Expressway. They performed a three-factor, four-level orthogonal numerical simulation experiment to conduct a sensitivity analysis of the surrounding rock. [PERSON], [PERSON] and others [10], based on the limit equilibrium theory, derived the expression for the ultimate support pressure on the excavation face of a shield tunnel. They studied the variation in ultimate support force and the tilt angle of the failure body during the process of shield tunneling approaching the interface between intact rock and fault fracture zones. [PERSON], [PERSON] and others [11] used theoretical analysis and discrete element numerical simulation methods, combined with field monitoring results, to conduct a comprehensive analysis of the case of tunnel construction through fault zones in high-speed railway projects. The study found that when a tunnel crosses a water-rich fault fracture zone, the rock mass is characterized by well-developed structural planes, with many planes filled with debris or clay fillings. [PERSON], [PERSON] [12], based on an engineering project, established a seepage numerical model to analyze the groundwater seepage patterns around the tunnel under different grout ring thicknesses and permeability coefficients. [PERSON], [PERSON] and others [13] studied the stability of a surrounding rock and structure when tunneling through a high-pressure water-rich fault fracture zone. By establishing a 3D fluid-solid coupling numerical model, they analyzed the distribution of the seepage field, protrusion deformation, plastic zone volume, water inflow, and shear deformation of the grouting reinforcement ring during face advance under different working conditions. [PERSON], [PERSON] and others [14], based on the Nanwan Tunnel of the Hong Kong-Zhuhai-Macao Bridge connecting line, established a two-dimensional analysis model using discrete element software PFC2D 3.1. The results showed that under the influence of fault fracture zones, the stress of the tunnel surrounding rock is asymmetric.