Experimental Study On Bearing Capacity Of RPC Pressure Pipeline And Preliminary Study On Its Design Theory

With the development of pipeline structure,especially the high head of hydropower stations and ultrahigh pressure transmission pipeline,the application of pressure pipelines is attracting more and more attention from engineering and academia.The current pressure pipeline is mainly used in the form of steel lined reinforced concrete penstocks(SLRCP)and Prestressed Concrete Cylinder Pipe(PCCP).However,in the long-term development and practice of prestressed pipeline,it is found that the above two pipe forms,including the early form of ordinary concrete pipe,result in a variety of defects and damage,and ultimately lead to structural bearing capacity decline or structural damage due to the limitations of the material itself(low strength,design errors,environmental factors)and other reasons.Thus,the use of new materials to innovate the structure of the pressure pipeline is particularly important In this context,this paper uses the Reactive Power Concrete(RPC)material,put forward the RPC pipe,innovated the pipeline structure form,and carried out the experimental research and design theory research on the new RPC pressure pipeline,made the preliminary Of the experimental results and theoretical analysis of the results,these results will be to promote the development of the pipeline structure of the source and will certainly achieve important theoretical and social and economic benefits.As a new type of ultra-high performance concrete,RPC concrete has the advantages of high strength,high toughness,high durability and high corrosion resistance,and basically satisfies the essential demand of concrete structure to the material.It has been successfully applied to the local and integral structure of the bridge,Thin-walled structure,nuclear safety shell structure,fire-resistant anti-corrosion structure and other fields.But in the application of the pipeline,at home and abroad there is its application prospects and potential analysis of the report,but the substantive research and application is still in the blank.In this paper,the theoretical analysis and experimental research methods are used to provide experimental support and theoretical support for the key scientific and technical problems in the application of RPC concrete pressure pipes.The main work is as follows:1.Through the literature review and engineering research,pointed out the mechanical properties of RPC materials and the advantages of its material,and the current main pressure pipeline structure during the operation of the problems were reviewed,to find the existing pipeline of scientific and technical problem and a new type of RPC pipeline structure is proposed for the existing problems of pipeline structure.2.On the basis of the existing pipeline design theory,the design theory of RPC pipe cross section is put forward.3.This paper try to prepare the RPC material and the compressive strength,prism compressive strength,flexural strength and elastic modulus of the RPC material were tested by experiment.The experimental results show that the compressive strength of the experiment is 149.7MPa,the compressive strength of the prism is 112.3MPa,the flexural strength reaches 19.2MPa,the elastic modulus is 50.8GPa.And through the test we can see that the standard deviation of the experimental results are between 0.92-5.7,which determine the nature of the RPC material is stable.4.In this experiment,the RPC pipeline was tested and the experimental study on the internal pressure bearing capacity of RPC pipe was carried out.In the experiment,the fracture development mechanism,the relationship between load and strain,the relationship between load and radial displacement and the cracking load of RPC pipe,the ultimate load and the ultimate load of pipe bearing capacity are studied by step loading.And points out the feasibility and advanced nature of RPC pressure pipeline.Experiments show that:(1)Unconfined RPC tube carrying capacity is far superior to the specifications of similar carbon fiber,glass fiber reinforced reinforced concrete pipe;(2)RPC tube with inner diameter of 500 mm and outside diameter of 490 mm,cracking load is about 0.93 MPa.After cracking of concrete,the steel fiber continues to bear the load,so the pipeline can continue to carry,and because of the constraints of steel fiber,crack development is slow,when the internal pressure increases to 1.08 MPa,the width of the crack reaches 0.2mm to reach the normal limit load,the radial displacement is about 1.4mm,and after the carbon fiber,glass fiber reinforced concrete pipe to achieve the normal use of ultimate load The resulting radial displacement is similar in size.5.On the basis of summarizing the whole paper,the paper puts forward the scientific and technical problems of promoting the application of RPC pipeline,and pointed out the direction of further efforts.At the same time,it is pointed out that the RPC material and the RPC pipeline structure have very bright application foreground.Based on the existing experimental and theoretical results,a new type of RPC-NC composite prestressed pipe is prefigured to make a further application for the RPC pipeline.Finally,the research results of this paper will contribute to the development of RPC pipeline structure.