Prototype Experimental Investigation of the Failure Mechanism and Crack Propagation of Segment Lining for Staggered Jointed Assembly

Abstract

In order to ascertain the failure characteristics of a segment structure with distributed mortises and tenons, one should be aware of the rules of key parameters and the development of cracks during the failure process. In this paper, based on the Foguan-Guangcheng Intercity Railway Tunnel Project, a prototype test of the structure of a segment with a staggered joint assembly was performed to study the local mechanical characteristics of the segment lining of the vault. The main conclusions were as follows: (1) The failure process in the test was classified as large eccentric compression failure, and the bearing capacity limit was M = 1993 kN m. (2) The overall displacement distribution of the segment structure was funnel-shaped, and the failure process was divided into three stages, that is, the elastic stage, the elastoplastic stage, and the plastic stage. Thus, it is recommended that the index of the single-point displacement limit of this tunnel be reduced appropriately to be between 1.5 and 1.8%. (3) The change rule of the longitudinal joint opening of the segment can be divided into three stages, that is, slow increase, accelerated increase, and sharp increase. For normal use, the limit of the opening of the longitudinal joint is set at 3 mm. (4) The width of the structural crack and the vertical displacement of the control section can be used as the safety evaluation index of this project. When either a large increase in the width of the crack occurs or the displacement specified above is reached, it can be considered that the structure is about to fail, and immediate protective measures must be taken.