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Study on Shear Mechanical Performances of Circumferential Mortise and Tenon Joints with Oblique Bolts in Shield Tunnelling
(1. Guangzhou Haizhu Bay Construction Co., Ltd., Guangzhou 510290; 2. Key Laboratory of Transportation Tunnel Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu 610031; 3. China Railway Siyuan Survey and Design Group Co., Ltd.,Wuhan 430063)
Abstract To investigate the shear mechanical performances and shear failure mechanisms of circumferential mor? tise and tenon joints with oblique bolts in super-large diameter shield tunnels, a study was conducted based on the Haizhu Bay Tunnel project in Guangzhou. A three-dimensional refined numerical model of circumferential segment joints was developed using a concrete plastic damage constitutive model. The deformation behavior, bolt stress, mortise and tenon reinforcement stress, and structural damage of the circumferential joints were analyzed under varying shear states and longitudinal forces. The results indicate that: The deformation of circumferential segment joints exhibits distinct phases under both forward and reverse shear conditions, comprising four stages. The shear stiffness of circumferential joints under forward shear state is higher than that under reverse shear state; The effect of longitudinal force on enhancing the shear stiffness of the circumferential segment joints is primarily observed in the first de? formation stage; Under forward shear state, bolt deformation is dominated by tension, whereas under reverse shear state, shear deformation prevails. Bolts quickly reach yielding once in contact with the bolt holes,respecially under reverse shear condition, where the contribution of bolts to shear stiffness is limited; Mortise and tenon reinforcement improves structural ductility and prevents brittle failure; Concrete damage at the contact points of bolt holes and mortise and tenon joints is characterized by compressive crushing. Compared to bolts, mortise and tenon features significantly enhance the shear stiffness and bearing capacity of the circumferential segment joints.
Abstract：
To investigate the shear mechanical performances and shear failure mechanisms of circumferential mor? tise and tenon joints with oblique bolts in super-large diameter shield tunnels, a study was conducted based on the Haizhu Bay Tunnel project in Guangzhou. A three-dimensional refined numerical model of circumferential segment joints was developed using a concrete plastic damage constitutive model. The deformation behavior, bolt stress, mortise and tenon reinforcement stress, and structural damage of the circumferential joints were analyzed under varying shear states and longitudinal forces. The results indicate that: The deformation of circumferential segment joints exhibits distinct phases under both forward and reverse shear conditions, comprising four stages. The shear stiffness of circumferential joints under forward shear state is higher than that under reverse shear state; The effect of longitudinal force on enhancing the shear stiffness of the circumferential segment joints is primarily observed in the first de? formation stage; Under forward shear state, bolt deformation is dominated by tension, whereas under reverse shear state, shear deformation prevails. Bolts quickly reach yielding once in contact with the bolt holes,respecially under reverse shear condition, where the contribution of bolts to shear stiffness is limited; Mortise and tenon reinforcement improves structural ductility and prevents brittle failure; Concrete damage at the contact points of bolt holes and mortise and tenon joints is characterized by compressive crushing. Compared to bolts, mortise and tenon features significantly enhance the shear stiffness and bearing capacity of the circumferential segment joints.
QIU Wei1 ZENG Qingcheng1 OUYANG Jian1 MU Haixing2 GUO Wenqi2 FENG Kun2 HU Dawei3
.Study on Shear Mechanical Performances of Circumferential Mortise and Tenon Joints with Oblique Bolts in Shield Tunnelling[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(6): 129-138
2024, Vol. 61 