Research And Application Of Long-distance Top Pipe Construction Technology In Municipal Water Supply And Drainage Construction

In the laying of underground pipelines,the pipe jacking method is the most commonly used form of construction method with undercut method.It has the advantages of reducing a large amount of earthwork,reducing demolition and saving construction land,little disturbance to the surrounding environment,and not interrupting the flow of people on the ground and logistics and transportation activities.It shows high social and economic benefits in engineering practice,especially Suitable for pipelines to cross buildings and roads,railway lines,and even crossing rivers.At present,mechanical pipe jacking construction has been widely used in more and more pipeline construction practices,mainly used in urban water supply and drainage,power pipelines,gas pipelines,heat pipes,communication cables and other construction.With the continuous improvement of the jacking distance,the depth of the pipeline is deeper and deeper,and the complex and diverse geological conditions,the underground pipe jacking construction technology is an urgent issue that people should pay attention to and consider.In this paper,in view of the more common and advanced pipe jacking construction technology in the current engineering practice,the control management technology involved in the construction of complex geological conditions,longdistance,ultra deep and large diameter mechanical pipe jacking in the construction process is deeply studied.Combined with the pipe jacking construction project of Wenzhou Binhai Avenue,the construction of the mechanical pipe jacking process is optimized.At the same time,the key technologies for mechanical pipe jacking construction are: equipment selection and adaptation,adaptive setting of grouting and anti-friction parameters,grouting process and grouting operation rules,setting between relays,measurement control management,jacking attitude Control and correction control management have been focused on analysis and research.Through the example of the bridge pipe project of Binhai Avenue,the above research contents are applied and verified one by one,and the deep foundation pit of the pipe jack is monitored at the same time to grasp the change of the pipe jack working well during the jacking process.It also analyzes and manages major hazards during the construction of mechanical pipe jacking.Finally,the economic benefits of mechanical pipe jacking are analyzed.It provides a lot of theoretical and practical reference for the future long-distance pipe jacking project.This paper proposes the selection basis of long-distance pipe jacking equipment under complex geological conditions,and optimizes the composite cutterhead mud-water balance pipe jacking machine for construction.The long-distance pipe jacking construction precision control technology is summarized,including earth pressure balance control,formation loss control and grouting anti-friction control,to meet the requirements of long-distance pipe jacking construction precision control.According to the complex stratum in the Binhai Avenue project,the mechanism of the pipe mud is analyzed,and the performance requirements of different formation muds and reasonable formula of the mud-water balance mud and lubricating mud of the pipe jacking are proposed to achieve efficient tunneling of different strata.In this project,during the jacking process,the pipeline was “locked” by the sand layer and the risk of the cutterhead being stuck.In order to eliminate the risk,the grouting and drag reduction,the jet blasting and the horizontal jetting were used to deposit the sediment.Scouring,slag cleaning and other methods have successfully eliminated the occurrence of risk accidents and have a very good effect.In short,the application of long-distance pipe jacking technology can reduce engineering cost to a certain extent,save engineering cost,and has good economic benefits.At the same time,the application of this technology can greatly improve construction efficiency,ensure construction progress,and improve on-site construction technology.It will be further developed in projects such as water supply and drainage,gas pipelines,track engineering,and integrated pipe corridors.