The Hong Kong–Zhuhai–Macau Bridge immersed tube tunnel project is the only deep buried and large siltation immersed tube tunnel in the world. There is no similar case in the world. Its stress deformation characteristics are different from those of conventional shallow buried tunnels. According to the traditional design method of immersed tubes, there will be a series of problems. To address these issues, a semi rigid pipe joint scheme between rigid and flexible pipe joints has been proposed. By comparing the forces acting on the joints with traditional types of pipe joints, the mechanical mechanism of semi rigid immersed pipe structures has been revealed. Compared with flexible immersed pipe structural systems, it improves the load-bearing capacity and water tightness of the segment joints, reduces the internal force of the immersed pipe structure, reduces the risk of concrete cracking, and solves the technical problems of deep buried large sedimentation immersed pipe structures. This can provide reference for similar projects.