Study On Mechanical Performance Of Precast Prestressed Utility Tunnel

With the contious advancement of urbanization and the proposal of the sponge city concept,the construction of Utility Tunnel is imminent.Due to the limitations of traditional construction methods,Utility Tunnel is necessary.This thesis reanalyzes the horizontal and vertical bending stiffness efficiency and its influencing factors of Precast Prestressed Utility Tunnel.At the same time,the differences in the stress of the two kinds of structure were studied.Combining field data to analysis the mechanical performance of prefabricated structures during construction.The details are as follow:Summarizes the applicability of Precast Prestressed Utility Tunnel,sectional form,longitudinal connection method,influencing factors of block number.Adapting the basic calculation method of structural mechanics to analyse the stress of Utility Tunnel in rectangular section.Got the calculate method of the effective formula for the lateral bending stiffness due to the presence of transverse joints.Combined Calculation Formula for effectiveness of Longitudinal Bending Stiffness of Shield Tunnels get the longitudinal bending rigidity of Utility Tunnel.Combined the calculation method for connecting joints of prestressed tendons get the longitudinal bending stiffness of Utility Tunnel.used Prestressed tendons to connect.Relying on the actual project,establishing a numerical analysis model for the overall castin-place and fabricated structures.the results are as follow:(1)Due to the presence of horizontal and vertical bolts,the prefabricated pipe corridors have undergone major changes in the mechanical properties on the roof and side walls of the structure.,the bolts bear most of the tensile stress and the concrete bears most of the compressive stress;(2)The lateral bendingstiffness effective value is 0.997;(3)The Longitudinal bending stiffness efficient of Utility Tunnel connected by longitudinal bolt is 0.5;the longitudinal bending stiffness efficiency of Utility Tunnel connected by longitudinal prestressed tendons is 0.8;(4)Tube section width has less effect on the efficiency of longitudinal bending stiffness,the number of longitudinal connecting bolts and the crosssectional area of longitudinal prestressed tendons have a greater effect on the longitudinal bending stiffness efficiency;Compared with on-site monitoring data and numerical simulation,get a effective numerical simulation method,derived structure under asymmetric loading,the rebars are still in the elastic stage.