Experimental Study On Flexural Mechanical Properties Of Socket Pipe Flexible Interface

Buried pipeline is an integral part of lifeline system,and its normal operation is of great significance to the life,life and property safety of the whole city and people.The pipeline interface is the weak link and the interface failure is the main failure mode.In recent years,flexible rubber ring joints have been widely used in urban water supply,gas and other pressure pipelines due to their good seismic performance.Therefore,it is of great theoretical and practical significance to study the response characteristics and failure mechanism of the flexible interface of the apron under earthquake action.At present,the main problem of water supply pipeline is the aseismic performance and normal water supply performance of pipeline interface,and there is still a lack of mechanical properties test research of pipeline interface under bending state.In view of this,this paper takes the flexible interface of ductile iron pipe as the research object,and carries out relevant experimental research on its bending mechanical performance and service performance under the action of transverse load:(1)Based on pipe ends of external constraints of a set of short tube ends,implements the finite rotation constraint test design concept on both ends of the pipeline,to DN150 mm,DN200mm and DN300 mm interface under three working condition of pipe diameter in the absence of water pressure transverse monotonic loading and reciprocating load bending test,considering the influence factors such as loading rate and loading mode,analysis for three kinds of diameter of contact Angle displacement value of 4.7 ° and 5.2 ° and 5.8 °,set up under different loading rate of bending moment-corner-the mathematical model of the mutual relations between axial displacement;(2)The service performance tests of three pipe diameters DN150 mm,DN200mm and DN300 mm were carried out,and the test water pressure was 0.2mpa.The analysis showed that the contact Angle of the three pipe diameters was basically the same as that of the non-hydrostatic test.It is proposed that the influence of loading rate on the interface performance mainly occurs after the interface Angle exceeds the contact Angle,and theloading mode has little influence on the pipe water supply function performance.The spatial mathematical model of rotation,axial displacement and water pressure under different loading rates is established.(3)Based on the test results and the stress process of the apron,the paper analyzes the three stages of bending deformation of the flexible pipe interface under transverse loading,and presents the interface hysteresis model under successive reciprocating loading mode with the influence of loading rate.The model results are consistent with the test results.