Mechanical Characteristics Analysis Of Prefabricated Pipe Gallery Under Vehicle Load

With the deepening of the concept of sponge city,urban underground Comprehensive Pipe Gallery is widely used in Municipal Engineering in major cities.Generally,the Comprehensive Pipe Gallery is directly buried under the urban road or green belt,which belongs to shallow underground structure and is more vulnerable to the influence of vehicle loads on the road surface.As an underground long strip structure,the longitudinal dimension of the comprehensive pipeline gallery is much larger than that of the cross-section,and there are many vertical interfaces.The additional effect of vehicle.load on the deformation joints of the pipeline gallery structure and the special section location such as the joint between prefabricated pipeline galleries may be more significant.’Based on a Comprehensive Pipe Gallery project in Jishou City,on the basis of field test and three-dimensional numerical model analysis,this paper studies the longitudinal and transverse mechanical behavior and response law of the comprehensive pipe gallery structure with Bell and spigot joint interface under vehicle loads.Considering the influence of the cross-section at the longitudinal joint of the Pipe Gallery,this paper deeply studies the stress and deformation of the underground comprehensive pipe gallery and its response to vehicle loads.It has important theoretical significance and engineering application value for the measures,so as to provide reference and guidance for the corresponding design and construction in practical engineering.The main work and conclusions are as follows:(1)In the backfilling stage of the construction of the Comprehensive Pipe Gallery,a certain number of earth pressure sensors are buried in each typical section of the gallery,and the law of earth pressure on each section of the comprehensive pipeline gallery is experimentally studied and the results are analyzed.(2)Stress sensors are installed on the roof,side wall and axillary angle of the Comprehensive Pipe Gallery structure,and the working conditions of different vehicle loading speed and different loading positions are designed.The stress response law of each part of the Comprehensive Pipe Gallery under vehicle loading is analyzed.The test results show that the middle part and axillary angle of the left and right side walls of the Pipe Gallery are compressed and the roof is pulled at the middle part of the span.The concrete manifestation is that the compressive stress decreases gradually along the height of the side walls to the axillary angle.From the axillary angle along the width direction of the roof to the middle of the roof span,the compressive zone becomes pulled zone,and the tensile stress increases gradually until the peak value of the tensile stress is reached at the middle part of the roof span.(3)Using finite element software ABAQUS,considering the socket interface and pipe-soil interaction of pipe gallery,a three-dimensional numerical model is established,and the half-wave sinusoidal amplitude curve is used to simulate the vehicle load,and the numerical analysis is carried out.The validity of the numerical model is verified by coMParing and analyzing the prototype test results of the pipeline gallery.On this basis,the influence of different load amplitude,different vehicle load location and different buried depth of pipeline gallery is considered.The analysis results show that the longitudinal stress distribution of the pipe gallery is discontinuous at each socket interface;the inside of the roof,the outside of the left and right side walls and the inside of the floor are pulled,the outside of the roof,the inside of the left and right side walls and the outside of the floor are pulled,and the stress deformation of the whole section presents the deformation trend of the roof,the bottom concave to the inside,and the convex to the outside of the left and right side walls.The influence of vehicle load is reduced.