Experimental Study on Mechanical Properties of Ductile-Iron Joint Panels for Segmental Joints in Deep-Buried Drainage Shield Tunnels

Abstract:

To study the applicability of DIJPs (ductileiron joint panels) suitable for deepburied drainage shield tunnels, positive bending moment tests for HSSJs with two different types of DIJPs were carried out, and the mechanical properties of DIJPs and the failure modes of HSSJs were analyzed. The experimental results show that: the failure characteristic of HSSJs subjected to positive bending moment, which is similar to the failure characteristic of the compressionbending section with large eccentricity, is that the bolts or the DIJPs yield firstly, and then the segmental joint fails with the concrete in the compressive zone broken. If the flexural rigidity of the DIJPs is sufficient, there is no deformation in the DIJPs, the bearing capacity of the segmental joint is higher, and the anchor bars reach their full potential; if the flexural rigidity of the DIJPs is insufficient, 5 mm bending deflection appears in the DIJPs, the bearing capacity of the segmental joint is lower, and the anchor function of anchor bars is not fully exploited.

Key words:deep-buried drainage shield tunnel; highstiffness segmental joint; ductile-iron joint panel; experiment