| The tunnel anchorage is one of the important load-bearing members of the suspension bridge,which has the advantages of economy and little environmental impact.However,the current understanding of the bearing mechanism of tunnel anchors is not deep enough,and is limited by engineering geological conditions,which to a certain extent hinders the development and application of tunnel anchors.This article takes the tunnel anchorage of China’s first railway suspension bridge-Lixiang Railway Jinshajiang Super Bridge as the research object,analyzes the engineering geological conditions in the area,and adopts a combination of indoor model tests and numerical analysis.The deformation law and failure mode were studied.The main content and results of this article are as follows:(1)The engineering geological conditions in the study area are analyzed,the physical and mechanical parameters of the rock mass around the tunnel anchor are determined,the stability of the bank slope of the tunnel anchor is evaluated,and the engineering geological characteristics are summarized.(2)Based on the principle of similarity,a 1: 200 geometric similarity ratio was used to design the material ratio,loading scheme,and monitoring method of the model test,and a 1:200 tunnel anchor slope drawing model was completed through sample preparation.(3)By loading the model and analyzing the surface deformation of the slope body and the internal deformation of the rock body,it can be concluded that the stability of the surface of the slope body and the surrounding rock is better under a single design load.Under overloading,the contact surface at the top and bottom of the rear end of the tunnel anchor is the most vulnerable zone,and the failure mode is that the shear sliding surface along the tunnel anchor contact surface is damaged.(4)Through the establishment of a three-dimensional geological model of the tunnel anchor in Lijiang,using FLAC3 D software for numerical calculations,after the step-by-step loading,it was found that the deformation impact range is about 1 times the hole diameter,and the maximum deformation is located in the surrounding rock contacting the middle of the tunnel anchor,along the tunnel anchor The body contact faces the surrounding rock of the anchor body to diffuse,and the attenuation is very obvious.(5)Through the comparison of model tests and numerical simulations,considering the safety of the project,it is concluded that the ultimate bearing capacity is 16 times the design load.The existing design still has surplus,and the design should be further optimized. |
