Research On Quality And Performance Evaluation Method Of Hdpe Plastic Steel Winding Drainage Pipe With Hybrid Process

In recent years,polyethylene pipes have been springing up in municipal engineering and gas transportation projects.They have the advantages of light weight,good moisture and corrosion resistance and strong impact resistance.Among them,steel reinforced spirally wound polyethylene drainage pipe is a new type of pipeline developed and applied by our country alone.It not only takes account of the advantages of traditional polyethylene pipes,but also rolls spiral steel strips outside the pipe wall,which can well enhance the overall ring stiffness and compression capacity of pipelines.However,a series of pipeline accident investigation results in Europe indicate that most of the pipeline failure or damage occurs at joints.The treatment of joints is the key and difficult point of quality control in site construction.At present,there are many ways of connecting polyethylene pipes.The operation of each connection is simple,and the economic cost is relatively low.However,each construction connection process has its own disadvantages.If there is a lack of constrains of construction technology regulations,the quality of connection will largely depend on the experience and operation technology of construction personnel.The quality of joint connection may be hidden.This paper is based on the research project of the hot-melt extrusion welding compositing with heat shrinkable strip of steel reinforced spirally wound polyethylene drainage pipe in the Sinohydro Bureau 7 CO.,LTD.In order to obtain better connection quality,the bonding process of hot melt extrusion welding compound heat shrinkable zone is considered.In order to achieve the above purpose,paper carried out a systematic test and analysis from the properties of raw materials,joint connection performance and full size pipe connection.It mainly includes the following research content and results:(1)The advantages and disadvantages of commonly pipeline connection methods,including flange connection,hoop connection,electric melting connection and hot melt butt joint,were compared.The points of attention and quality control were summarized and analyzed in the site operation connection operation.In addition,the construction points and operation difficulties of these traditional connecting processes are taken in view of the site operation of combined connection process.And it is used to standardize the operation process,control quality and completion acceptance of the combined connection process;(2)In this paper,a single hot-melt extrusion welding joint and a single heat shrinkable joint are tested respectively.The effects of different construction control parameters on the tensile properties,bond performance and water permeability of the joint were investigated to obtain the best construction control parameters.However,no matter what joint connection technology is used,it is necessary to clean the tube wall and heat shrinkable belt which will be connected.And it is necessary to ensure that the surface of the connection is smooth and clean all the time;(3)The test is based on the construction recommendation parameters of the hot melt extrusion welding and the composite heat shrinkable strip connection process.The mechanical properties of the specimens processed by the combined connection process are tested,including the tensile properties and the water permeability.The test results show that the tensile strength of the combined joint is higher than the tensile strength of the raw material.In addition,in the water tightness test of the combined joint,the water surface of the specimen has no leakage in the back surface and has good water permeability;(4)During the test of the ring stiffness test,the deformation of the pipe from the top to the middle of the pipe gradually becomes larger.But the welding liquid and heat shrinkable belt at the pipe junction remain intact during the whole compression process,and there is no breakage or damage.And the ring stiffness of pipe can reach the SN8 level basically;(5)The basic performance tests of connection materials and various process connection joints were carried out.According to the performance test data,the qualified performance parameters are determined,including the tensile strength of PE connection material,the tensile strength of the joint,and the ring stiffness of the pipe.On this basis,a comprehensive performance evaluation method for connection material and joint quality is proposed.