Research On The Numerical Analysis And Engineering Application Of Suspension Bridge’s Tunnel Anchorage

The anchorage system is an important part of the suspension bridge, the anchorage system of suspension bridge can be generally divided into gravity anchorage, soil anchorage and tunnel anchorage. For the construction of suspension bridge in mountainous, tunnel-type anchorage has a huge advantage compared to others, because of the advantages like small amount of engineering, low cost, and the suitability of surrounding environment. However, at present, there are few examples of the tunnel-type anchorage engineering. Besides, the study on stress and failure mechanism of the anchorage are still not clear, so the research of tunnel type anchorage is necessary. In this paper, we study the stress and deformation of tunnel anchor in the engineering background of Dandong combat readiness bridge, and intend to provide some reference for similar engineering design method. The main contents of this paper can be divided into the following parts:(1)On the basis of previous research, we sum up the tunnel-type anchorage in the existing engineering structure form, the probable failure mode of anchorage system, and the calculation method of anchorage system stability.(2) We study certain key problems in numerical calculation of tunnel-type anchor including initial stress field simulation method, comparison of different yield condition of rock and soil materials, analysis points of soft interlay simulation method contact, and realization method of numerical simulation of the anchorage in construction process.(3) Establish bond anchorage-surrounding rock system model and calculation friction model with Ansys. We study the deformation law and the failure process of anchorage system with the change of the main cable force. By studying the difference of force between bonding model and friction model, and comparing key results of two models, we obtain the applicable scope of bonding model.(4) Setting Dandong combat readiness bridge as example, we put forward the structure design of the bridge tunnel-type anchorage. Using the software of Midas, we establish 3D elastic-plastic numerical calculation model of anchor-surrounding rock system, and analyze anchorage system at the construction stage and the operational stage. We obtain the deformation characteristics of anchorage system at the construction stage and the operational stage. We verify the stability of surrounding rock in tunnel construction process of anchor, and we prove anchorage system is safe enough, and at the operation stage, it has seven times overload stability.