Study On Seismic Response Analysis And Influencing Factors Of Utility Tunnel

Underground utility tunnel is a modern and intensive urban lifeline infrastructure integrating many kinds of municipal pipelines.Because of its high utilization rate of shallow underground space and good disaster prevention,underground utility tunnel can effectively solve various problems of traditional buried pipelines in current urban areas.With the rapid development of economy and the sharp increase of urban population,China vigorously advocates the construction of utility tunnel at the present stage,and lots of cites are carrying out the construction of utility tunnel.However,there are only few studies on seismic design of underground utility tunnel as well as its relevant design codes,it is necessary to put forward the seismic performance research of utility tunnel.Therefore,the dynamic response of underground utility tunnel under seismic loads was investigated with the numerical simulation in this study,.And the main work were listed as followings:(1)Introduced the relevant data of seismic research of utility tunnel including seismic response characteristics and common research methods.(2)Expounding basic knowledge needed in the analysis of dynamic response of underground utility tunnel under seismic loads by ABAQUS.First,the basic theory of dynamic finite element analysis was introduced.followed with the introduction of Mohr-Coulomb model of soil,damage plasticity model of concrete and soil-structure interface theory.Then,the theory and input method of dynamic infinite element boundary and consistent viscous-spring boundary were elaborated,the precision of and the two artificial boundary was precisely descripted with a simple example comparation.And finally,we also explained the selection of seismic wave.(3)The finite element models of ten kinds of utility tunnel with different cross-section sizes was established to analyze the dynamic response of utility tunnel with corresponding seismic loads.the influence of section size change on seismic response of utility tunnel was analyzed with taking acceleration amplification factor,relative displacement of roof and floor,and maximum mises stress as reference values.At Last,the law of section size change with seismic response parameters of utility tunnel was characterized.(4)Based on the finite element model of utility tunnel established in Chapter(3),some factors that may affects the seismic response of underground utility tunnel was analyzed with using single variable method,including the spectrum characteristics of seismic wave,the magnitude of peak acceleration of seismic wave,the propagation mode of seismic wave in soil,soil stratification and the buried depth of structure.We also employed a similar methods compared with chapter(3),the acceleration of floor,the relative displacement of roof and floor,the maximum mises stress were all investigated in this study to understand the relation between those factors and the seismic response of utility tunnel.What’s more,based on our research,we also put forward several relevant suggestions for seismic design.