Research On The Design Of The Crossing Method Of The Yonglong Pipeline In The Yangtze River

With the rapid development of our country's economy,the demand for energy is also increasing,pipeline transportation,as the main means of energy transmission,occupies a very important role in modern industrial production and people's life.Oil and gas pipelines are generally long,and through terrain is complex.As a control project of long distance pipeline project,river crossing is of great significance in measuring the level of engineering construction and ensuring the progress of projects.Although there are many river crossing methods,but due to the special topography?hydrology?engineering geology?environment?transportation and other conditions,The choice of crossing is not the same,Therefore,choose the right way of crossing is particularly important for ensuring the progress of the project,saving investment,guarantee the safe operation of pipeline and susainable development of regional ecological environment.Based on the actual project as an example,first collect survey data,through the project of geological?hydrological and environmental conditions,we get the based design conditions;Secondly,combined with the survey data and analysis the common crossing modes in pipeline engineering,three traversing ways of directional drilling crossing,cofferdam excavation crossing and underwater excavation are preliminarily proposed;Finally,through the design and comparison of the three ways,we take underwater excavation as a result,reference value for similar crossing project.this paper has completed the following four work:(1)Sort out the survey data,Through the collection of the topography,regional geological structure,the underlying structure and site hydrology of the crossing location,we get the environmental profile of the crossing point,and provide a basis for design and comparison.(2)Analysis the common way of crossing,by enumerating common excavation and non excavation crossing methods and combined with the general situation of the project,compare the characteristics of different ways,preliminarily selecte three kinds of drilling crossing,cofferdam excavation crossing and underwater excavation;(3)To design the crossing mode,through draw plan and section map,it can be seen more intuitively;Check the pipeline according to the formula,Guaranteeing the stress of pipeline to meet the project requirements;To design the pipeline stabilization and cross strait protection,which improve the content of the project;Put forward the construction proposal and risk analysis of different schemes,and discusses the feasibility of the scheme;(4)Compare the way of crossing,combined with the design,comparing the geological conditions,feasibility,construction period and investment,and finally get the way of underwater excavation.The results and ideas of this paper can provide useful reference for the pipeline river crossing in China to a certain extent.