Analysis Of Cyclic Grouting Simulation In Prestressed Concrete Beam

Prestressed technology can effectively improve the carrying capacity of the structure to solve the problem of difficult to break through in the span of concrete components and enhance the crack resistance of the structure,so it is widely used in bridge engineering.Duct grouting has the synergistic effect of increasing the prestressed structure and preventing the exposed corrosion of the prestressed tendon,which is the main construction step of the post-tensioning method and has an important influence on the safety and durability of the prestressed bridge.In this paper,the prestressed channel of standard prestressed beams is taken as an example.The FLUENT software is used to analyze the cyclic grouting process.First,according to the model of prestressed duct,obtain four major stages of the cyclic grouting process,which is initial phase,initial phase,Enrichment stage,Enrichment stage of grouting.It's easy to store air at pulp outlet and upper port of duct which fluid velocity lower through analysis cement slurry volume fraction distributed.The comparison between the recycle grouting process and the traditional grouting process is carried out.The analysis of the experimental results shows that the traditional grouting process is easy to have the gap at the seal anchor,making some of the prestressing tendons exposed to the air.The recycle grouting process can ensure that the channel Grouting quality and prevent grouting defects.Secondly,the duct pressure grouting process under different inlet pressure was studied.The distribution of volume fraction of cement slurry in each working channel was analyzed and curve fitting was carried out.The calculation results show that the increase of inlet pressure will improve the efficiency of duct pressure grouting construction.Through the analysis of the inlet and outlet flow under each condition,it can be concluded that the duct pressure grouting can be considered as the same inlet and outlet flow rate.Therefore,monitoring the flow of inlet and outlet can be regarded as one of the main parameters for controlling the quality of grouting.Finally,the fluid flow in the bellows was studied.The accuracy of the computational model is verified by comparing the two-dimensional symmetry model and the three-dimensional straight tube model with the empirical formula.The comparison of the pressure drop between the corrugated pipe model and the smooth pipe model shows that the pressure drop of the spiral corrugated pipe is larger than that of the smooth straight pipe.By analyzing the six kinds of field parameters,it can be concluded that the corrugated structure can form eddy structure in the pipe wall and cause Low-speed area,leading to increased resistance along the way.The analysis of the structural parameters of the corrugated pipe shows that increasing the corrugation spacing can reduce the interaction between the corrugated structures,reduce the complicated flow area in the pipe wall area and reduce the resistance loss along the pipe.Increasing the corrugation depth can deepen the formation of eddy structure and lead to Eddy current region closer to the interior corrugated,corrugated pipe to increase the resistance along the way to increase the bellows pressure drop.In this paper,through the study of cyclic grouting technology and fluid flow characteristics in bellows,it can provide corresponding construction basis for engineering practice.