Analysis Of Mechanical Properties And Fatigue Damage Of Fabricated Utility Tunnel Under Vehicle Load

In recent years,massive urban underground comprehensive utility tunnel in domestic cities are being built.However,due to the influence of construction conditions and construction costs,the existing comprehensive utility tunnel are mostly constructed with open cut methods.They are mostly located just below the motor vehicle lanes and are buried at a shallow depth.It is affected by the long-term impact of the dynamic load of the motor vehicle above it.For comprehensive utility tunnel,under the long-term dynamic load of motor vehicles,the stress concentration locations such as corners and joints of rectangular pipeline corridors may cause stress fatigue damage and lead to structure damage.The current domestic and international research status focuses on the bearing capacity characteristics of comprehensive utility tunnel,and does not consider the impact of mobile dynamic loads.Based on this,this thesis adopts the method of numerical simulation and uses the ABAQUS finite element method for the analysis of fabricated utility tunnel under the load of motor vehicles.The main research contents are as follows:(1)Under the static load of motor vehicle,the mechanical properties of the untility tunnel,the difference between the finite element method and the conventional structural design in the distribution of the soil additional stress at the top of the untility tunnel,the influence of tunnel stiffness,tunnel depth,the relative positional relationship between tunnel and roadwas analyzed.(2)Under different kinds of dynamic load of motor vehicle,the dynamic response law of the unility tunnel and the stress or addition stress concentration position of the unility tunnel,was analyzed.And analyze the position of possible horizontal joints.(3)The load-carrying performance of two types of tunnel joint and the destruction of the tunnel joint was analyzed and compared.Under moving wave loads of motor vehicles,the dynamic response law of assembly-type unility tunnel was analyzed.The fatigue life of different kinds of assembly-type unility tunnel was predicted.The advantage and disadvantage of different kinds of assembly-type unility tunnel was compared.