Field-Scale Experiment on Deformation Characteristics and Bearing Capacity of Tunnel-Type Anchorage of Suspension Bridge

The suspension pipe bridge has become the main span type due to its large span, light structure, and other characteristics, playing an important role in the construction of the oil and gas backbone network and energy layout. Tunnel-type anchorage (TTA) is a special underground structure that provides anchorage tension for the suspension bridge. Since its form and bearing mechanism are complex, there is no general design method for tunnel-type anchorage so far, and the theoretical and normative research is not mature. In this paper, a field-scale experiment was carried out to study the north side tunnel of Wujiagang Bridge in Yichang, China. According to the similarity principle, the 1:12 tunnel anchor scale model was established. The tunnel anchor scale model is selected in the area adjacent to the actual project site to ensure the similarity of stratigraphic conditions. Through the use of a displacement meter, inclinometer hole, strain gauge, micrometers, and other comprehensive monitoring methods, the design load test, overload test, overload rheological test, and ultimate bearing capacity failure test were carried out. Through the structural deformation observation and stress observation of the anchorage body and surrounding rock, the stress deformation characteristics and rheological characteristics of the anchorage body and surrounding rock in the field-scale experiment were analyzed. The deformation failure mechanism, deformation failure process, potential failure mode, and overload capacity of solid tunnel anchor were studied. The control indexes such as deformation and stress values of key parts of the solid tunnel anchor at different stages are predicted. Based on the limit equilibrium analysis results of the model, the safety and rationality of the tunnel anchorage structure design of the actual suspension bridge were evaluated.