Dynamic Response Of Utility Tunnel Under The Effect Of Oblique Incidence Of Ground Motions

Utility tunnel is a typical kind of shallow buried underground structure.Compared to the traditional way of buried pipeline,utility tunnel can solve many problems in the process of the implementing urbanization.It also creates a good platform to exploit underground space and unify the needs of management system.Nowadays,China strongly supports the development of utility tunnels.Cities are being built,and on the other hand it is also the hope for creating a sponge city in the future.However,the existing specifications of seismic design interaction for underground structures is still needed to meet the goal.We need to take the reference of seismic design of tunnels,subways and other underground structure.There are much difference on the seismic response between the underground structure and utility tunnel.Therefore,it cannot offer a reliable reference to realize economic and security goal.Based on the existing experiments and theories,this paper uses finite element analysis software to study its seismic performance.Through the numerical simulation research for an actual engineering of utility tunnel,it observes the dynamic response law of utility tunnel,surrounding soils and internal pipeline under the condition of oblique incidence input of the earthquake motion.It also make the summary of its potential destruction and develop the interpretation for this phenomenon.This research provides the proper consideration and recommendations for the seismic design accordingly.The main content of this article is as follows:First,this research sort and expound the related theory by observing current situation of the development of utility tunnel,the oblique incident seismic input implementation and the soil-structure interaction.Then,the equivalent load calculation formula is deduced based on the establishment of a uniform viscous-elastic artificial boundary.All the computations performed and programs implemented in MATLAB to calculate the value of multiple surface of different notes.The model is verified about the the rationality and accuracy of the earthquake motion input and boundary condition.Second,create a model of underground utility tunnel in accordance with the reference of the existing utility accordingly.The constitutive model of the concrete properties is selected including the plastic damage parameters.Establish the model in the finite elementsoftware(ABAQUS),and realize oblique incidence input of the ground motion.The model is then analyzed in accordance with the response law under dynamic action,then,respectively discusses response law and failure criteria of the soil,the utility tunnel body and the internal pipeline under dynamic load.Third,the soil material parameters,input of different ground motion amplitude and the changes of values with the depth of buried utility tunnel were studied by analyzing the important factors that may have the influence of dynamic response law of utility tunnel.Then,analysis the parameters from the results of numerical calculation of the monitoring of displacement,stress and peak acceleration amplification coefficient and so on.The results show that the response of utility tunnel is less secure when the earthquake propagates in oblique input motion than the ordinary motion.The top corner points of utility tunnel are most prone to damage.The inner partition of the roof as well as floors are also dangerous positions under dynamic loading.In conclusion,all of this parts mentioned are needed to perform reinforcement design.