Study On Bearing Characteristics And Calculation Method Of Tunnel Anchorage Structure

In recent years,the strategy of "Western Development" has been gradually promoted,and suspension bridges have been widely used in mountainous southwest areas.Tunnel-type anchorage,as a new type of anchorage structure of suspension bridge,has been widely used in engineering design for its advantages of adapting to local conditions,economy and environmental protection.Due to the complexity of interaction mechanism between anchorage body and surrounding rock,there is no consensus on the bearing characteristics and ultimate uplift bearing capacity of tunnel-type anchorage.In this subject,theoretical derivation,numerical simulation analysis and indoor model test were combined,and the load bearing characteristics and calculation method of the tunnel anchorage under inverted wedge failure mode are studied.:(1)The indoor model test was designed and carried out.Through the step-by-step loading,the displacement of the tunnel anchorage from the initial state to the failure process was studied,and the surface displacement distribution law and the load displacement curve of the anchor plug body were obtained.(2)The three-dimensional model of tunnel-type anchorage was established,and the numerical simulation analysis was carried out through the finite element software FLAC3 D.The displacement,stress and plastic zone change law of anchor plug and surrounding rock under design load and multiple load were studied by loading respectively,and the whole failure process of tunnel-type anchorage was obtained;the similarities and differences of failure surface curve and load displacement curve between homogeneous and heterogeneous surrounding rock were compared;compared with the model test results,the consistency of failure mode,uplift bearing capacity and displacement law was analyzed.(3)The inverted wedge failure mode of tunnel-type anchorage was analyzed,and a feasible failure model was established.Based on the upper limit analysis method,the calculation method of ultimate uplift bearing capacity was deduced,and the calculation method of ultimate bearing capacity of tunnel anchorage under curved failure mode was obtained.Combined with the test data,the feasibility of the calculation method of the ultimate uplift bearing capacity of tunnel anchorage was verified,the applicable environment was analyzed,and the calculation errors were compared...