Model test on anti-dislocation performance of Borokonu-Aqikukuduke fault traversing tunnel

The geological conditions in the western region of China are complex, and many tunnel projects inevitably traverse unfavorable geological sections during construction, facing threats from active faults. To explore the strain response law and deformation failure mechanism of tunnel with flexible joint under strike-slip fault dislocation, with the background of the Shengli tunnel project in the Tianshan mountain, we use optic fiber sensing technology to conduct small-scale indoor model tests to study the deformation and failure of segmented articulated tunnels under strike-slip fault dislocation. The results indicate that the overall fault failure mode of the tunnel is a combination of tension, compression, and shear. And the deformation of the tunnel lining is mainly concentrated in the interior and near the edge of the fault fracture zone. Along the longitudinal direction of the tunnel, the stress mode of the tunnel at the fault fracture zone is generally tensile at the top and bottom of the arch, with both sides being both tensile and compressive. Along the circumferential direction of the cross-section, the circumferential strain distribution shows a "W" shape, with two tensile strain peaks and two compressive strain peaks. The deformation tendency of the section is that both sides are subjected to horizontal compression, forcing the section to develop from horseshoe shape to oval shape. This study reveals the deformation and failure form of tunnel with flexible joint under strike-slip fault dislocation, as well as the deformation patterns of the lining, which can provide theoretical reference and technical support for similar projects in the future.