Study On Dynamic Response Characteristics Of Shallow Buried Pipe Gallery Structure Under Vehicle Load

The integrated pipe gallery is directly buried under the urban road, which is a typical shallow buried underground structure. The live load borme by the pipe gallery structure is mainly the vehicle vibration load above the road. Shallowly buried underground structures cannot form natural arches to offset the impact of vehicle load vibration. Compared with deeply buried underground structures such as subways, vehicle load vibrations have more significant effects on the dynamic response characteristics and failure damage of pipe gallery structures. Therefore, it is particularly important to study the dynamic response characteristics of shallow buried pipe gallery structures under vehicle vibration loads. Based on the background of an underground comprehensive pipe gallery project in Xr’an, this paper uses the method of combining theoretical calculation and model test to obtain the dynamic characteristics of the shallow buried pipe gallery"structure affected by vehicle vibration, and proposes a method for the shallow buried pipe gallery structure affected by vehicle vibration.Vibration isolation measures for vibration effects. The main research results are as follows:(1)The causes and propagation characteristics of vehicle vibration load is analyzed, and it is found that road surface roughness, vehicle weight and vehicle speed are the main causes of vibration. Based on the calculation theory of the vehicle load on the underground structure,combined with the fact that the shallow buried pipe gallery structure cannot form a natural arch, the mechanical characteristics and deformation mechanism of the shallow buried pipe gallery structure under the vehicle vibration load are obtained.(2)The calculation model of vehicle vibration load is determined as simple harmonic dynanic load. On the basis of the distribution angle method, combined with the mechanical characteristies and deformation mechanism of the shallow buried pipe gallery structure, a vehicle-shallow buried pipe gallery structure mechanics calculation model is established. By applying D’Alembert principle, the equilibrium differential equation of the dynamic responseof the shallow buried pipe gallery structure under the vehicle vibration load is constructed.The Wilson-θ integral method is used to solve the problem,and the dynamic response calculation expressions of the displacement,velocity and acceleration of the shallow-buried pipe gallery structure under the vehicle vibration load are obtained,which can provide a theoretical reference for the structural design of the shallow-buried pipe gallery.(3)Based on the similarity theory,the material,size and action load of the shallow buried pipe gallery were determined,and the stratum simulation material was prepared.Combined with the mechanical calculation model,simple harmonic dynamic loads of different amplitudes and frequencies are applied,and the model test of the dynamic response of the shallow buried pipe gallery structure under the vehicle vibration load is carried out.The structural response characteristics of the shallow buried pipe gallery under the vehicle vibration load are obtained.The pressure of the top plate is obviously greater than that of the bottom plate,and the maximum value is at the center line of the structure,showing the characteristics of stress in the middle and low at both ends.The dynamic response of the structure to the load frequency is more severe than the vibration amplitude.It is clarified that the main influence range of the shallow buried pipe gallery structure under the vehicle vibration load is 0.45 m to 1.05 m when the buried depth is 6 m,that is,within the range of 6times the pipe diameter in the horizontal direction.(4)The theoretical calculation method of the shallow buried pipe gallery structure under the vehicle vibration load is compared and verified with the dynamic response law obtained from the model test,and the rationality of the theoretical calculation method is verified.In view of the vibration source,the propagation path and the vibration body,some vibration isolation measures,such as local strengthening structure,deformation joints and concrete diaphragm walls,are proposed.It provides a reference for the stability analysis and safety evaluation of the shallow buried pipe gallery structure under the vehicle vibration load.