Research On Key Issues Of Pipeline Repair By By Grouting Anchor Lining Method

The grouting anchor lining method is an emerging trenchless pipeline repair technology,and its theoretical research lags behind its engineering application.Based on the lining method,this paper focuses on the annular gap between the old pipeline and the lined pipe,and launches the research on the key problems of the lining method pipeline repair.The main work and results are as follows:(1)Summarize the principle of determining the height of the annular gap in the grouting anchor lining method;propose corresponding solutions to the grouting quality problem of the annular gap in the repair process of the grouting anchor lining method,and summarize the grouting density detection method.(2)Calculations based on the existing specifications show that: when only the role of the lining pipe is considered,and the role of the anchoring key is not considered,the lining pipe cannot meet the load-bearing performance requirements after the pipeline is repaired.The existing standard wall thickness calculation formula used in the grouting anchor lining method has limitations.Based on the thick-walled cylinder theory and strength theory,the calculation formula of the theoretical minimum thickness of the grouting layer in the grouting anchor lining method repair is deduced in detail,and the theoretical explanation for the optimization of the grouting layer material is given.(3)Regarding the internal support during grouting,the two situations of inflation pressure and water injection pressure are considered,and the calculation formula for the pressure of the liner pipe is deduced.Regarding the buckling problem of the lining pipe in the old pipeline,based on the Glock model and the principle of minimum potential energy,the calculation formula of the critical buckling pressure of the lining pipe under internal pressure is deduced,which provides a theoretical basis for determining the grouting pressure.(4)The diffusion law of the slurry in the annular gap is studied,and the corresponding mathematical model is proposed.The mechanism of the anchoring key on the lining pipe of the quick-grid pad is studied,the formula for calculating the pull-out force of the anchoring key is deduced,and the influencing parameters of the anchoring effect are analyzed,which provides a theoretical basis for optimizing the design of the anchoring key parameters.And when considering the effect of the anchoring key,the calculation formula of the buckling pressure resistance of the liner in the composite pipe is deduced,and the anchoring key parameters when the anchoring effect is better are obtained.At this time,the critical buckling pressure of the liner is higher than that of no anchoring key.The buckling pressure was increased by 26.31 times.(5)The influence of different inner lining thickness on the bearing capacity and maximum deformation of the composite pipe was studied through laboratory experiments.The test shows that compared with the old pipeline,the increase rate of the inner lining thickness and the maximum bearing capacity of the composite pipeline basically meets a linear relationship.Comparing the composite pipes with different inner lining layers,it is found that as the thickness of the inner lining layer increases,the increase rate of its bearing capacity decreases significantly.The increase rate of the maximum deformation of the composite pipe increases with the increase of the thickness of the inner lining,but the increase rate of the increase rate gradually decreases.