Study On Seismic Response Analysis And Shock Absorption Measures Of Underground Utility Tunnel

The urban city underground utility tunnel is to collect power,water supply,radio,gas and other municipal pipelines into an underground space,which is an important infrastructure for the operation of the city lifeline system.Once underground utility tunnel is damaged by an earthquake,it is likely to cause incalculable damages and loss.Therefore,on the basis of dynamic analysis theory,this paper takes the underground utility tunnel of Zhengzhou International Eco-Aquapolis in Jingkai District as the engineering background,establishes the finite element model of interaction between soil and tunnel structure,and carries out the following dynamic response analysis and research on the utility tunnel:(1)The modal analysis of the utility tunnel is carried out and the analysis results shows that the vibration of the utility tunnel is mainly controlled by the deformation of the surrounding soil,and the transverse vibration controls the structure of the utility tunnel.(2)According to the site conditions,the EL-Centro seismic wave is selected and the dynamic response of the utility tunnel structure under horizontal,vertical,and horizontal-vertical coupled earthquakes is analyzed by finite element method.It is concluded that the dynamic response of the utility tunnel structure under horizontal-vertical coupled earthquake is close to that of horizontal earthquake,and horizontal earthquake plays a leading role.Moreover,The tensile stresses at the cross section of the joint between the top plate and the middle wall,the cross section of the joint between the bottom of the left and right sidewalls and the bottom plate are large,which are the weak links under the earthquake.(3)The influence of concrete strength,soil property,seismic characteristics and burial depth on the seismic response of the utility tunnel structure was analyzed systematically.The displacement of utility tunnel structure decreases with the increase of the concrete strength,but the stress increases gradually,flexible materials are recommended for seismic design when the utility tunnel meets the static bearing capacity of the structure.The displacement and stress of the utility tunnel structure decrease with the increase of the soil stiffness,the greater stiffness the soil is,the better the structural anti-seismic will be.The low-frequency components of the seismic wave play a leading role in the seismic response of the tunnel,and the high-frequency component has less influence.On the premise of satisfying the structural strength,for a shallow structure such as the utility tunnel,the deeper the buried depth is,the smaller impact of the earthquake on the utility tunnel will be.(4)The shock absorption effect of the utility tunnel under different shock absorbing materials and different shock absorption layer thicknesses is analyzed.The analysis results show that setting a shock absorption layer between the utility tunnel and the soil is a very effective shock absorbing measure.The absorbing effect of the rubber absorption layer is more obvious than that of foam absorption layer.The greater the thickness of the absorption layer is,the better the shock absorption effect will be.The suitable thickness of the shock absorption layer should be selected according to the actual conditions such as the site condition,the structural characteristics and the project cost in the concrete project.