Study On Service Performance Of Prestressed Concrete Cylinder Pipe With Broken Wires

Prestressed Concrete Cylinder Pipe is a new type of composite pipe with excellent performance,which is widely used in long-distance water transportation projects at home and abroad.However,during service,PCCP is affected by factors such as corrosion,hydrogen embrittlement,and material defects.The pre-stressed steel wires in the pipeline may have broken wires,which will reduce the strength of the pipeline,which will seriously cause the core concrete to crack,Canister damage,or even tube burst accidents,has severely affected people's production and life.This paper uses field prototype tests and numerical simulation analysis to focus on the load-carrying mechanism and failure process of broken wire PCCP under service conditions,and aims to provide a reference for the operation management and structural safety evaluation of in-service PCCP.The main research contents of this article include the following aspects:(1)A full-scale internal pressure test was carried out on an embedded PCCP with an inner diameter of 2.8 m,including an intact pipe loading test,a pipe broken wire test,and a broken wire pipe loading test.Mainly tested the strain response of core concrete,prestressed steel wire and protective layer mortar under internal hydraulic pressure,observed and analyzed the crack distribution and development law of broken wire pipeline during internal hydraulic pressure loading,and studied prestressed steel wire The effect of fracture on the structural performance of the pipeline,the bearing mechanism of the broken wire pipeline and the failure process.(2)Based on the actual structural parameters of the broken wire pipe in the prototype test,a PCCP three-dimensional nonlinear finite element numerical model of the broken wire considering the grip force of the mortar was established.By comparing and analyzing the numerical simulation results of ABAQUS software and the measured data of the prototype pipeline test,the rationality of the numerical model of the broken PCCP was verified.Furthermore,based on the prototype test,by changing the number of broken wires in the pipeline and the internal water pressure in the numerical model,the effect of broken wires on the bearing capacity of PCCP was further studied.(3)Based on the Mp CCI platform,combined with ABAQUS software(establishing a PCCP three-dimensional non-linear numerical model that considers pipe-soil interaction and socket structure characteristics)and Fluent software(establishing a fluid model in the pipe),the fluid-solidity of a broken wire pipe under service is achieved Coupling numerical simulation,and in-depth study of the influence of different number of broken wires,different broken wire positions and operating hydraulic pressure on the mechanical response of PCCP.