Mechanical Response of Segmental Tunnels Subjected to Reverse Faulting: Physical and Numerical Modeling

Underground tunnels crossing active reverse faults are highly vulnerable to permanent ground deformation, which may significantly affect their structural integrity and operational performance. This study investigates the behavior of segmental tunnels subjected to reverse-fault displacement using an integrated approach combining centrifuge testing and three-dimensional finite element modeling. The numerical model developed in ABAQUS was verified against centrifuge experiments, showing excellent agreement with the experimental observations, with prediction errors of only ۲% for maximum ground settlement and ۴% for maximum tunnel crown displacement. Following model validation, a comprehensive parametric study was conducted to evaluate the influence of reverse fault angle (۶۰°, ۷۵°, and ۸۵°), soil stiffness, tunnel overburden (۱۰-۲۰ m), soil friction angle, and tunnel diameter (۵-۱۰ m) on tunnel performance. The results demonstrate that increasing the reverse fault angle substantially intensifies ground settlement, tunnel crown displacement, tunnel S-shaped deformation, and lining ring rotation while expanding the fault-affected zone. Increasing soil stiffness reduces ground settlement but promotes more complete upward propagation of fault rupture and increases localized tunnel deformation. Increasing tunnel overburden decreases both ground settlement and tunnel displacement by dissipating fault-induced deformation within the surrounding soil mass. In contrast, changes in the soil friction angle alone have only a negligible influence on tunnel behavior. Furthermore, increasing tunnel diameter has a limited effect on global settlement but reduces the plastic strain concentration above the tunnel and modifies the fault rupture path.

کلیدواژه ها:

Segmental tunnels ، fault ، Numerical Modelling ، Parametric study ، Centrifuge ، ABAQUS