Random Vibration Analysis Of Coupled Soil-Tunnel Systems Against Seismic Loadings

With the development of economics and society,people begin to feel unsatisfied with paying attention only to the exploitation of the land.Laying undersea tunnels have been an essential way of transportation developing in many countries in the world,since they have great abilities to achieve long range transportations and low construction costs.However,it is difficult to validate the safety of undersea tunnels for they are difficulty to detect.People used to think that earthquakes have slight effect on tunnels,so it never be a key problem to consider that is connected to earthquakes.However,with a great amount of tunnels destroyed in earthquakes around the world,people begin to realize the importance of anti-earthquake design of tunnels.The anti-earthquake design of tunnels has become a key problem to research,since it is much different from those of structures on land.With a background as this,this paper shows the research of coupled soil-tunnel structures against static and seismic loads.Considering the natural feature of earthquakes,conduct stationary and non-stationary random vibration analyses of coupled structures.Details as follow:Firstly,the history of tunnel strictures is reviewed,and important parameters,models and loads are followed,and the normal ways of anti-earthquake design and the studies of the behaves of tunnel structures against seismic loads are introduced.In Chapter Two,conduct static analysis of cross section of tunnels,equal stiffness ring model,hinges model and beam-spring model are used,and soil loads,earth reactions are considered,analyze the response behaviors of deformation and internal forces.In Chapter Three,a pseudo excitation method to analyze the random vibration of coupled soil-tunnel structure is proposed.The proposed method takes an advantage over traditional CQC method in computational efficiency.Then solve the response of model under stationary random loads with the pseudo excitation method,verifying the effectiveness and efficiency of the method proposed.In Chapter Four,a pseudo excitation method to solve non-stationary random vibration of soil-tunnel coupled structure is developed.The time-variance of internal force of tunnel is solved by the method developed.Results show dynamic responses of the structure is close related to modulation functions for non-stationary random vibration excitations,and that soft soil influences the dynamic responses more significantly than other types of soil.