大断面矩形隧道预制装配式管片接头抗剪性能研究

Study on Shear Behavior of Prefabricated Segment Joints in Large Section Rectangular Tunnel

为研究大断面矩形隧道预制装配式管片接头抗剪力学性能,依托某暗挖顶管式大断面矩形车站工程项目,通过对纵向接缝的原型抗剪试验,获得剪力和纵缝错动变形的五阶段关系曲线:第一阶段基本没有错台,剪力尚未克服接缝处的静摩擦力;第二阶段错台缓慢增长,剪力尚未克服接缝处的最大摩擦力;第三阶段错台快速增长,此时剪力已经超过接缝处最大摩擦力;第四阶段错台增长较上一阶段缓慢,此时凹凸榫参与抗剪;第五阶段错台快速增长直至纵缝破坏。通过试验数据分析得到纵缝抗剪刚度,明确各阶段抗剪受力机制,提出了第一、二阶段和第四、五阶段抗剪强度的实用计算公式。

In order to study the shear mechanical properties of prefabricated segment joints in large cross-section rectangular tunnel,based on a large cross-section rectangular station project with mined excavation and pipe jacking,through the prototype shear test of longitudinal joints,the five-stage relationship curves between shear force and dislocation deformation of longitudinal joint are obtained:in the first stage,there is basically no dislocation,and the shear force has not yet overcome the static friction at the joint;in the second stage,the dislocation deformation grows slowly,and the shear force has not yet overcome the maximum friction at the joint;in the third stage,the dislocation deformation increases rapidly,and the shear force has exceeded the maximum friction force at the joint;in the fourth stage,the growth of dislocation deformation is slower than that in the previous stage,and at this time,the concave convex tenon participates in the shear resistance;in the fifth stage,the dislocation increases rapidly until the longitudinal joint is damaged.The shear stiffness of longitudinal joints is obtained through the analysis of test data.The mechanism of shear resistance in each stage is clarified,and the practical calculation formulas of shear strength in the first,second,fourth and fifth stages are put forward.