Research On Repair Technology Of Urban Drainage Pipeline And Its Engineering Application

In recent years,the failure of drainage pipes in China has led to road collapse accidents frequently,which have seriously affected People's Daily life and economic property.Pipeline replacement costs are expensive and construction conditions are complex,which not only makes the pipeline industry face great public pressure,but also usher in new challenges.Trenchless technology has the advantages of small environmental impact and short construction period,which solves this problem within a certain range.This paper studies on the influence factors of lining thickness in trenchless pipeline repair and the application of finite element simulation in pipeline repair examples,which provides strong support for the design of lining thickness in pipeline repair under complex working conditions.The main research contents are as follows:(1)By arranging the data of the municipal drainage pipelines in Xi'an,the proportion of the total length of the reinforced concrete pipelines in the municipal drainage pipelines in different years was obtained.By counting the drainage pipelines of several communities in Xi'an,the sewerage system includes a separate system,a combined system and an incomplete separate system.The sewer pipe density averages are 106.23km/km2,90.97km/km2,and 81.68km/km2 respectively.The construction years of 30 communities are randomly counted.The results show that the sewer pipes laid in the 1980s accounted for the largest proportion.(2)Select the pipe diameter DN600 as the typical representative sewage pipe,and use the finite element software to simulate the UV curing method pipeline repair process.Under the same load,the pipe lining thickness is between 0-25mm,the equivalent stress of the pipe.The value and deformation value decrease as the thickness of the liner increases.Solve the original pipe and increase the thickness of the inner lining of 0-25mm respectively to correspond to the ultimate bearing capacity.(3)Selecting the pipe diameter DN1000 as a typical representative rainwater pipe,assuming that the pipe contains 70 mm hole defects,using the theory that the allowable stress of the pipe material is constant,the simulation results show that the optimal spray repair thickness is 30 mm when the elastic modulus is 30200 MPa.Change the spray material to 37800 MPa and find the optimum spray thickness of 25 mm.(4)The finite element simulation results are verified in the engineering example.The pressure sewage pipeline A with the pipe diameter of 600 mm is selected,and the thickness of the inner lining is designed to be 6 mm.The bearing capacity of the pipeline after inspection and repair meets the requirements;the reinforced concrete pipe B of section DN1000.After the spraying thickness is 30 mm,the test results of the pipeline meet the standard and meet the finite element simulation results.