Numerical Simulation Of Repairing By Polymer Grouting For Drainage Pipeline Voids

With the accelerating process of urbanization in China,the construction of urban infrastructure such as drainage pipes has entered a stage of rapid development.As one of the five modern transportation modes,the pipeline has been widely used in municipal,electric power,communication,gas,water supply and drainage.Since most of the drainage pipes are buried underground,under the influence of various loads,due to the leakage of the pipeline,the void and the subsidence of the foundation,the pipeline will have different deformations.As a result,the pipeline may be damaged at the weakest point.As a new technology for underground pipeline leakage and void repair,polymer grouting technology can quickly fill the void and solve the leakage problem,but there are few researches on the theory of high polymer grouting to repair the evacuation drainage pipeline.In view of the above situation,this paper carried out the numerical simulation study on the Force deformation characteristics of the drainage pipe and the high-polymer grouting for repairing the hollow pipe,aiming at providing a theoretical basis for the maintenance and repair of the existing drainage pipe hollowing disease.The main research contents are as follows:(1)By studying the theoretical model of pipeline,the theoretical model of soil and the theoretical model of pipe-soil interaction,the finite element model of cement concrete drainage pipe is established,and the factors such as load size,load position,tube bottom void size and buried depth are analyzed.The effect on the mechanical properties of the drainage pipe.According to the data comparison,the interface of the pipe voiding part is more susceptible to tensile damage under load.When the applied load on the upper part of the pipe gradually increases,the stress and strain on the pipe gradually increase.As the position of the load is shifted,the deformation of the pipe is asymmetrically distributed.The stress and strain of the pipeline occurs at the boundary between the soil at the bottom of the pipe and the space at the intersection.The size and depth of the void have a great influence on the pipeline.(2)Fluent software was used to simulate the flow diffusion process of polymer slurry in the void part of the pipeline,and the influence of grouting amount on the pressure of the void was analyzed.Applying the pressure of the slurry over time to the void of the pipe.The influence of the expansion and diffusion process on the stress and strain of the pipeline after the filling of the high polymer slurry was completed by finite element software.And the deformation of the pipeline after the grouting repair is completed.The larger the initial slurry volume,the greater the expansion force at the same time.The theoretical grouting amount is obtained by calculation.(3)Carrying out on-site test of high-polymer grouting repair of void drainage pipe,use the drop-type deflection device(FWD)to load.Comparing the test results of the unloaded pipeline and the high polymer grouting repaired pipeline under different load sizes and different load positions with the numerical simulation results,monitoring the lift force of the slurry on the pipeline and the deformation of the pipeline during the grouting process.The trend of the two can be well matched,which proves the correctness and rationality of the numerical simulation results.