Study On Seismic Response Analysis Of Utility Tunnel With Shock Absorption Layer

The underground utility tunnel is an underground structure which is built in an urban and integrates heat supply,water supply,drainage,communication,electric power,fuel gas and other municipal pipelines and implements unified planning,unified management and unified maintenance.Various pipelines master the fate of urban development and is a power source for urban high-efficiency operation.Once an underground utility tunnel is damaged by an earthquake,a difficult-to-estimate loss can be caused.Therefore,taking an underground utility tunnel in Hunnan District of Shenyang as the engineering background,a three-dimensional finite element calculation model of the interaction between soil and utility tunnel was established.The following analysis and research work was performed on the underground utility tunnel using dynamic analysis theory :(1)Select EL-Centro wave and Taft wave according to site conditions,adjust the acceleration peak value to 7 degrees rare earthquake fortification requirements,and use the finite element analysis method to analyze the circular utility tunnel structure response without shock absorption layer,with shock absorption layer under horizontal earthquakes under two working conditions.Moreover,the stress on the arch shoulder and arch foot nodes is relatively large,which is a weakness under earthquake.(2)The effects of the shape of the section of the utility tunnel,the subdivision method of the utility tunnel,and the thickness of the utility tunnel wall on the seismic response of the utility tunnel system were systematically analyzed.Circular section utility tunnel curve is smooth,which facilitates the dispersion of stress,so the seismic performance is better than rectangular section.The vertical subdivision method can increase the horizontal stiffness of the utility tunnel structure.Therefore,the seismic performance of the vertical subdivision method is better than the horizontal subdivision method under the action of horizontal earthquakes.Regardless of the subdivision method,the stress on the connection between the partition wall and the structure is relatively large,and the connection needs to be strengthened in the project.Increasing the thickness of the wall,means increasing the overall stiffness of the utility tunnel,seismic action relative displacement values between each node gallery structural tube,the acceleration value is decreased,thereby increasing the pipe rack structure resistant to deformation under the action of an earthquake ability.(3)According to the arrangement mode of different shock absorption layers,the damping ratio of different shock absorption layers and the damping effect of different shock absorption layer thicknesses are quantitatively analyzed.The result shows that the shock absorption layer on the left side and the right side of the comprehensive pipe gallery plays a main role in the deformation limit of the structure under the action of the horizontal earthquake,and the stress of the shock absorption layers on the upper and lower sides has an obvious protection effecton the stress of the structure.The larger the damping ratio of the shock absorption layer,the better the shock absorption layer effect.The higher damping ratio of the shock absorption layer has a significant effect on the absorption of seismic energy and improving the seismic capacity of the utility tunnel.When the thickness of the shock absorption layer reaches a certain value,the influence of the thickness of the shock absorption layer on the stress and deformation performance of the utility tunnel will become smaller,and even the stress and acceleration values of the structure will rise without dropping.The optimal selection range approaches a fixed value.