Research On Dynamic Response And Deformation Control Of Loess Tunnel Base In Heavy Load Railway

Heavy load transportation is an important direction of railway freight development in China,but under the effect of large axle load,during the transportation,some tunnel bases were damaged by cracks at the bottom,mud pouring and other diseases,these diseases are more serious in Tunnel Base with larger collapsibility.Therefore,it is of theoretical significance and practical value to study the dynamic influence characteristics of Tunnel Base under the load of heavy-duty train,analyze the settlement and deformation law of tunnel basement,and formulate deformation control measures.The dynamic response of the heavy-duty train to the tunnel under the vibration load is analyzed,and the load application method of the heavy-duty train is discussed,used artificial excitation to simulate train vibration load,and the load time history curve of the heavy-duty train acting on the tunnel base structure is obtained through the finite element analysis.Based on the Shilou tunnel in the middle and south of Shanxi Province,a three-dimensional dynamic model of tunnel base of heavy-duty railway is established,the dynamic response characteristics of tunnel base are analyzed,and the influence law of axle load on the dynamic response of tunnel bottom structure is obtained.Based on the increment of displacement,acceleration and stress at the bottom of the tunnel,the influence of the rise span ratio of the inverted arch,the thickness of the filling layer,the thickness of the inverted arch and the thickness of the bottom layer on the dynamic response of the bottom structure of the Loess heavy haul railway tunnel is analyzed,and the relationship between the base reinforcement parameters and the dynamic response of the Loess heavy haul tunnel is obtained.Based on the increment of displacement,acceleration and stress at the bottom of tunnel,the influence of rise span ratio of invert,thickness of filling layer,thickness of invert and thickness of pavement on the dynamic response of tunnel bottom structure of loess heavy haul railway is analyzed,the relationship between the foundation reinforcement parameters and the dynamic influence of the Loess heavy load tunnel is obtained.The damage mechanism of the railway tunnel transportation basemen is analyzed,the reinforcement scheme of loess heavy load railway tunnel base is optimized,the Countermeasures for grouting reinforcement of basement are put forward,the vertical displacement and acceleration of the invert center and the peak stress of thelining are compared before and after grouting reinforcement,the feasibility of the construction technology of grouting reinforcement of loess tunnel base of heavy load railway is verified.