Development And Mechanical Properties Of Easy-locking And Fastening Embedded Channel

The embedded channel is a new type of structure used to fix integrated pipelines,electromechanical and other equipment in the tunnel.The difference from the traditional embedded channel technology is that the fastening embedded channel is to lock the anchor rod and the channel through the locking screw.In the later operation of the project,if the channel is damaged,it can be maintained and replaced.In view of the complex defects of traditional embedded channel positioning and demoulding,starting from the practical engineering problems,this paper develops a kind of easy-locking and fastening embedded channel,which realizes the accurate locking of embedded channel and mold,and is conducive to the demoulding of concrete components.In view of the fact that scholars at home and abroad rarely conduct a comprehensive and systematic analysis of the mechanical properties of fastening embedded channels,this paper uses a combination of theoretical analysis,finite element analysis and experiments to study the mechanical properties of fastening embedded channels.The main contents of this paper include:1.The structure of the embedded channel is easy-locking and fastening.Aiming at an easy-locking fastening embedded channel developed in this paper,the characteristics of the easy-locking device of the embedded channel in the positioning phase and the fastening embedded channel in the use phase are introduced from two aspects of structure and working principle.Pliers-shaped plastic parts are arranged inside the channel,which can lock the embedded channel and the mold and improve the demolding efficiency;a locking screw is added inside the fastening embedded channel,and if the channel is damaged,it is easy to maintain and replace.2.Analysis of mechanical properties of easy-locking and fastening embedded channels.The main factors affecting the mechanical properties of the fastening embedded channel are introduced,and the failure mode and ultimate bearing capacity of the fastening embedded groove under axial tension and shear load are analyzed.In order to study the deflection of the easy-locking device of the embedded channel under the lateral pressure of the newly poured concrete,the device was simplified and a theoretical calculation formula was proposed.The results show that: 1)Under the axial tension load,the concrete cone is damaged,and the tensile bearing capacity of the fastening embedded channel is 151.97 k N;2)Under the shear load,the T-bolt is sheared,and the shear capacity of the fastening embedded channel is 192.92 k N;3)The deflection of the embedded channel easy-locking device under the lateral pressure of the newly poured concrete is 0.205 mm,which is within the allowable deviation range of the channel construction.3.Finite element analysis of easy-locking and fastening embedded channel.The finite element software ABAQUS is used to simulate the embedded channel with easy locking,and the failure mode and ultimate bearing capacity of the embedded channel with easy locking under axial tension and shear load are analyzed,as well as the mechanical performance of the embedded channel with easy locking device under lateral pressure of concrete.The finite element results show that: 1)Under the axial tension load,the concrete cone failure occurs,and the tensile bearing capacity of the fastening embedded channel is 143.08 k N;2)Under the shear load,the T-bolt shear failure occurs,and the shear capacity of the fastening embedded channel is 205.52 k N;3)The deviation of the comparison between the finite element analysis result and the theoretical calculation result of the fastening embedded channel is within 10%,which verifies the rationality and accuracy of the finite element analysis;4)Under the lateral pressure of concrete,the overall displacement of the embedded channel easy-locking device is 0.27 mm,which meets the construction requirements of the channel,indicating that the embedded channel easy-locking device is effective and feasible.4.Mechanical performance test for fastening embedded channel.The material properties of the main components of the fastening embedded channel were tested.The mechanical properties of the specimens of the fastening embedded channel were tested,and observed the failure process and failure modes of the fastening embedded channels and the ultimate bearing capacity,and compare the test results of the fastening embedded channel with the finite element analysis results and theoretical calculations.The test results show that: 1)Under the axial tension load,the T1～T3specimens are all concrete cone failure,and the average tensile bearing capacity is152.2k N;2)Under the shear load,the S1～S3 specimens are all T-bolt shear failures,and the average shear capacity is 193.67 k N;3)The test results of the fastening embedded channel are basically consistent with the theoretical calculation,and the deviation of the finite element analysis result is within 10%,indicating that the mechanical performance analysis of the fastening embedded channel has a certain degree of reliability.