CIPP修复内衬-埋地柔性管道复合结构受力特性数值模拟研究

Numerical Simulation Study on Mechanical Characteristics of Liner-Buried Flexible Pipe Line Composite Structure by CiPP Repair

柔性管道广泛应用于地下管网工程中,但随着使用年限增加,大量柔性管道亟待修复。原位固化法(curried in place pipe,CIPP)是一种常用的非开挖管道修复技术。为研究CIPP修复内衬-埋地柔性管道复合结构的受力特性,构建了土体-埋地柔性管道-内衬相互作用的二维有限元模型,并通过与土箱模型试验结果进行对比验证了有限元模型的可靠性。通过参数敏感性分析讨论了内衬弹性模量、内衬壁厚、管周土体密实度和初始椭圆度对CIPP修复内衬-埋地柔性管道复合结构的影响。研究结果表明,内衬最大应变发生在试样两侧与管顶呈约65°处,且管顶的应变大于管底;内衬危险点的局部应变峰值随着内衬弹性模量的减小而增大,而内衬整体的应力应变水平随之降低;管周土体密实度与复合结构承载能力成正相关,且内衬危险点随着管周土体密实度的降低而向管顶移动;随着埋地柔性管道初始椭圆度的增大,复合结构的刚度随之减小,危险点的应变峰值增大。该研究结果可为CIPP修复设计提供参考。

Flexible pipelines are widely used in underground pipeline engineering.With the increase of service life,a large number of flexible pipelines are urgently needed to be repaired.Curied in place pipe(CIPP)is a commonly non excavation pipeline repair technique.In order to study the mechanical characteristics of liner-buried flexible pipeline composite structure by CIPP repair,a 2D finite element model of soil-buried flexible pipeline-lining interaction was constructed.The reliability of the model was verified by comparing with the results of soil box model tests.The influence of lining elastic modulus,lining wall thickness,soil density around the pipe and initial ellipticity on the CIPP repair was discussed by parameter sensitivity analysis.The research results indicate that the maximum strain of the lining occurs at a position with about 65 from both sides of the sample to the top of the pipe,and the strain at the top of the pipe is greater than that at the bottom;The local strain peak at the dangerous point of the lining increases with the decrease of the elastic modulus,while the overall stressstrain of the lining decreases accord-ingly;The compactness of the soil around the pipe is positively correlated with the bearing capacity of the composite structure,and the dangerous points of the lining move towards the top of the pipe with the compactness decreases of the soil around the pipe;With the initial ellipticity of the buried flexible pipeline increases,the stiffness of the composite structure decreases,and the peak strain increases at the dangerous point.The research results can provide reference for CIPP repair design.