Study On Grouting Technology Of Prestressed Pipeline Based On Slurry Pipeline Transportation Theory

In post-tensioned prestressed concrete structure,prestressed pipeline grouting is one of the key procedures.In order to ensure the permanent high effective stress of prestressed tendons in beams,high quality pipeline grouting is carried out,and the corrosion of prestressed steel bundles caused by the infiltration of external moisture is avoided,so as to ensure the durability of prestressed bridge structures.With the continuous development of prestress technology,the durability caused by grouting quality of prestressed channels must be attached great importance to.In this paper,the grouting technology of prestressed pipeline is studied by using the theory of slurry pipeline transportation.The main contents are as follows:(1)The formula applies to the verification test.The value of the pressure change in the whole test process is compared with the calculated value of the relevant formula,and the applicability of the pipe diameter,the inclination angle,the length and the like under different conveying conditions is compared,and the formula is used in the test.(2)Modified the conveying speed test of slurry in prestressed bellows.The transportation speed of slurry in smooth pipe wall is compared with that in prestressed bellows,and the velocity attenuation value is obtained,and the reliability of the coefficient is verified under different lengths,pipe diameters and concentrations.(3)Modify the conveying speed of slurry in prestressed bellows mixed with prestress tendons.By adding different root numbers of prestress tendons,the velocity attenuation coefficients under different root numbers are obtained.It is verified that the attenuation coefficient is still reliable under the condition of changing the concentration.The reliability of the experimental results under different pipe diameters is further verified by experiments.(4)Field grouting enough scale verification test.By calculating the modified conveying speed under the field transportation condition,the starting point pressure of the grouting inlet under the field working condition is further obtained,and the pressure is used to guide the grouting.The grouting process was observed to be unobstructed and no pipe blockage was found.On the basis of the above tests and theoretical analysis,the pressure required for grouting is calculated from the speed of slurry transportation,so as to guide the grouting construction,optimize the grouting process and avoid pipeline blockage and compaction.