Seismic analysis and design of tunnels within fault ground: A review

Underground tunnels tend to be more vulnerable when crossing or near undesirable geological structures such as faults and large discontinuities, etc., resulting in structural loosening, cracking, spalling, dislocation, and even collapse in the event of seismic activity. Extensive and in‐depth research is required to comprehend the interaction mechanism between the fault ground and the tunnel structures. In this paper, the current main research methods and mitigation techniques of tunnels within fault ground are systematically reviewed. Initially, the field observations of structural seismic damage regarding the fault are reviewed. Subsequently, four main factors influencing the degree of tunnel damage are extracted. Then, the potential causes of damage to tunnels caused by faults during seismic events are listed. Next, the current main research methods, including analytical solutions, physical experiments, and numerical simulations, are summarized separately. The function of self‐designed devices in model experiments is a key focus. Subsequently, the discussion turns to mitigation strategies and reinforcement materials for tunnel structures. Finally, some research and design gaps for tunnels within fault ground subjected to earthquake forces are outlined, along with a summary of the findings. Overall, this work is expected to provide valuable guidance for enhancing seismic capability and optimizing the seismic design of tunnels within fault ground.