Study On The Resistance To Settlement Difference Of Cast-in-situ Composite Pipe Gallery Deformation Joints

In order to make full use of urban underground space and solve the problem of laying urban public pipelines,China is accelerating the pace of construction of urban underground comprehensive pipeline gallerys.As a linear project,the pipe gallery section itself has a longer segment,and the cast-in-place comprehensive pipe gallery is one of the main construction forms of the current urban underground comprehensive pipe gallery.It is clearly stated in the GB50838-2015 specification that the cast-in-place construction method is adopted.When designing the longitudinal deformation joints of the pipe gallery structure,the separation distance should be less than 30 m.Therefore,at least one deformation joint is arranged within 30 m in the length direction of the comprehensive pipe gallery.The joint design of the deformation joints between the sections of the pipe gallery plays an important role in adapting the integrated pipe gallery to uneven settlement.At present,the experimental research of pipe gallerys is often the seismic study of the joints of prefabricated comprehensive pipe gallerys,and the experimental research on the longitudinal joints of cast-in-situ composite pipe gallerys is extremely scarce.necessary.This article mainly carried out the following aspects of work:(1)Based on the research background of the above comprehensive pipe gallery,on the basis of actual projects,a sample model of the comprehensive pipe gallery structure was designed to explore the different layout methods,different anchoring lengths and different concrete strengths of the pipe gallery’s shear reinforcement Parameter,design and produce four test pieces.(2)The monotonic static loading test of the comprehensive pipe gallery specimen was designed,which can simulate the stress characteristics of the pipe gallery segments and the shear anchor bars,study and analyze the bearing capacity,ductility and other stress performance of each specimen,and study The cause of damage and the mechanical properties and failure mechanism of the test piece.The results show that the failure mode of the four specimens is that the shear anchor bars have reached their actual yield strength first,and then the pipe gallery structure is destroyed.The final failure of GLJ-1—GLJ-3is the brittle failure of floor splitting,and the final failure mode of GLJ-4 is the failure of shear anchor bars.There is no obvious relationship between the settlement resistance of the specimen and the depth of the shear anchor bars and the strength of the concrete.The limit displacement of the specimen GLJ-4 with the shear anchor bars on the side walls is much larger than that of the first three specimens.Severe damage occurs,and the antisettlement performance is better within a certain settlement range.(3)MIDAS FEA finite element software is used to establish the finite element model of the test piece,and the numerical simulation results output by the software are compared with the test results to verify the validity of the numerical model.The parameter analysis of the diameter of the shear anchor bars is carried out.The analysis results show that the shear anchor bars have reached their yield strength and the diameter of the shear anchor bars has a significant effect on the structural settlement resistance.