Numerical investigation of seismic response of utility tunnels crossing ground fissure under earthquake excitation

It is widely accepted that ground fissure movement can cause severe damage to structures. However, the seismic effects of ground fissures on underground structures has not been thoroughly investigated. In particular, the seismic vulnerability of utility tunnels crossing ground fissures remains insufficiently understood. To address this gap, this study examined the seismic response of utility tunnels crossing ground fissures using finite element simulations. The analysis accounted for nonlinear soil behavior and soil-structure interaction. Furthermore, a parametric analysis was conducted to assess the effects of the tunnel-fissure intersection angle, fissure inclination, and initial dislocation on the seismic damage to the tunnel. The results showed that earthquakes caused large relative displacements between the hanging wall and footwall, leading to significant tunnel damage. The utility tunnel crossing ground fissure experienced vertical dislocation and buckling, particularly near both sides of the fissure. In contrast, tunnel sections farther from the fissure remained comparatively stable. The most severe structural damage occurred at the tunnel–fissure intersection. Seismic damage increased when the fissure inclination was smaller, the tunnel-fissure intersection angle was lower, and the initial dislocation was larger. These findings provide essential guidance for the seismic design of utility tunnels in adverse geological conditions. • Ground fissure effect on utility tunnels is considered in the proposed 3D numerical study. • Noticeable relative movement between the hanging wall and footwall under earthquakes led to substantial damage to the tunnel. • Preliminary evaluation and quantification of seismic damage in utility tunnels crossing ground fissures under earthquake. • Effects of fissure inclination, intersection angle, and initial dislocation on the seismic damage of tunnel were addressed.