Research On Seismic Dynamic Response Of Pipelines At The Branch Of Utility Tunnel

Nowadays,the investment in infrastructure construction increases with the accelerating process of urbanization in China.With the characteristics of effectively utilizing underground space resources,improving urban environment and disaster prevention and resilience ability,and reducing post-operation cost and etc,utility tunnel will gradually become the inevitable choice for urban development.In China,most cities are in an earthquake-prone belt.Under the earthquake,pipelines at the branch of utility tunnel are prone to be damaged and cause secondary disasters,posing a serious threat to people's lives and property.Therefore,it is of great theoretical and practical significance to study the seismic performance of the pipelines at the branch of utility tunnel and to ensure the normal operation of the pipelines.This thesis is based on the seismic analysis theory of overhead pipeline and buried pipeline and use ADINA software to analyze the effective stress and deformation of the pipelines at the branch,and to study the dynamic response of pipelines at the branch of utility tunnel as well.The main achievements of this thesis are as follows:(1)Based on the analysis of the seismic damage characteristics of overhead pipeline and buried pipeline,to conduct an analysis of the seismic damage characteristics of the pipeline at the junction for pipe.(2)Proposes the structure forms and combination modes of the branches of the comprehensive pipe galleries,according to which establish a theoretical analysis model for the junction for pipe.(3)Analyze the effective stress of the pipeline at the branch of utility tunnel under the seismic waves.The results show that under the action of seismic wave,the non-buried section of the branch pipeline of the utility tunnel is more prone to damage.(4)Study the influence of seismic wave input direction on the effective stress of the pipeline.The impact of seismic waves direction to the pipeline is:?_z>?_x>?_y;When the buried depth of the branch pipe varies from 1.0m to 3.5m,the effective stress of pipeline increases with the increase of buried depth,but the increments gradually decrease;The effective stress and deformation caused by the seismic load on the pipeline of Class I site are the smallest,and the effective stress and deformation caused by the seismic load of the pipeline of Class II,III and IV site increase first,then gradually stabilized,the impact of degree:?_?>?_?>?_?;Study the seismic intensity on the effective stress of the pipeline.The study found with the increase of earthquake intensity,the effective stress and deformation of the pipeline also increase.When the seismic intensity changes from?to?,the effective stress and peak acceleration of pipeline increase linearly.When the intensity of the earthquake reaches?and?,the effective stress and deformation of the pipeline increase rapidly which shows great damage to the pipeline.(5)The comparison between the seismic response of the buried pipe and the branch pipe of the utility tunnel shows that:under the seismic waves,the maximum effective stress of buried pipelines is about 3 times of pipelines at the branch of utility tunnel,and the maximum deformation is about 2 times.Besides,compared with the tee of buried pipelines,the maximum effective stress of pipelines at the branch of utility tunnel is about 6 times,and about 10 times of the maximum deformation.