Analysis On The Disease Characteristics And Study On The Influence Of Mine Goaf On WaChangping Highway Bridge

Bridge is the main traffic form across the mountain area,which is very sensitive to the deformation and movement of the surface.In our country,many bridge sections need to cross the mining area.The ground movement and deformation caused by the mined out area can easily reach or exceed the maximum allowable deformation value of the bridge,which has an impact on the structural deformation of the bridge and seriously affects the safe operation of the bridge.Taking the wachangping bridge section of Yaxi high speed over a goaf in Southwest China as an example,through field investigation,the paper grasps the signs of deformation and damage of the bridge,analyzes the deformation and damage characteristics and deformation trend of the overlying bridge in the goaf from time and space,and summarizes the characteristics of abnormal deformation of the bridge section in the goaf.Starting from the root cause of the goaf,the surface deformation index value of the goaf is predicted by theoretical calculation,and the evolution process of the influence of the goaf on the surface along the bridge is studied by numerical simulation.Finally,relevant suggestions are put forward for the deformation treatment of the bridge.Through the above research,we can get:1.Through the field investigation,the signs of bridge deformation and damage are mastered,which are mainly manifested in the cracking and deformation of bridge piers and connecting beams,the cracking of subgrade and pavement,the cracking of anti-collision guardrail,the extrusion or tensile deformation of expansion joints,etc.2.The deformation characteristics and deformation trend of the research are analyzed from many angles,which provides a basis for bridge evaluation and treatment.3.Based on the theoretical calculation and relevant specifications,the surface deformation index values along the goaf are predicted and analyzed,so as to evaluate the site stability along the goaf and the impact of bridge deformation.4.Combined with numerical simulation,the study shows that the goaf formed in2017 is the main factor causing the ground movement and bridge deformation in this area.5.Based on the summary of highway bridge treatment measures in goaf,this paper puts forward some measures and suggestions from the aspects of bridge foundation reinforcement,bridge structure reinforcement and coal pillar protection in goaf.