Study On The Influence Of Open-pit Blasting Vibration On Buried Oil Pipeline

With the rapid development of modern economy,buried pipelines are commonly used in various fields such as natural gas,oil,water supply,electricity and communications.Buried pipelines have become an emerging mode of transportation.At the same time,large-scale construction of basic projects in China often requires rock excavation,blasting,pile driving and other operations,and cannot completely avoid or bypass buried pipelines criss-crossing.These projects have greater vibration effects and are closer to the buried pipeline,which may cause pipeline damage and even serious consequences.Therefore,it is particularly important to control the damage of the blasting vibration to the pipeline during the blasting operation.This article takes the background of the earth and rock blasting construction of the Shugang Avenue backfilling project in the west area of Yantai Port as the background,and takes the buried oil pipelines around it as the object.Combining theoretical analysis,on-site monitoring and numerical simulation,the stress response law of buried oil pipelines under different soil media and different pipe diameters is analyzed.It provides a certain reference for the safe operation of buried pipelines under the action of blasting vibration.First,the thesis analyzes the destruction effect of earth-rock blasting on the pipeline from the aspects of the blasting and crushing mechanism of existing rocks,the formation and propagation of blasting seismic waves,reflection and transmission,and the characteristics of pipelines affected by seismic waves.It is concluded that the propagation of seismic waves is affected by many factors,and the blasting seismic waves reflect and transmit at the interface of media with different wave impedances.When the blasting seismic wave propagates to the pipeline,the front blasting surface of the pipeline is first subjected to blasting shock,and the back blasting surface is prone to tensile damage.The main frequency of blasting vibration has little effect on the pipeline.Secondly,the finite element software is used to simulate the stress process of the buried pipeline under blasting.A three-dimensional finite element model of the buried pipeline was established,and a multi-material fluid-solid coupling algorithm was used to divide the grid to analyze the change law of effective stress on the buried pipeline.The stresses on the front and back explosion surfaces are much higher than those on the top and bottom of the tube,and the effective stress on the front and back explosion surfaces is greater than that on the back explosion surface.Then,conduct on-site tests and monitoring,and use the Sadovsky formula to perform linear regression analysis on the results of on-site monitoring,and obtain a blasting vibration velocity attenuation formula suitable for the local geological conditions.The regional blasting vibration provides a scientific basis for prediction.Finally,using the model to verify the accuracy,the stress analysis of the buried pipeline caused by blasting vibration under different backfilling soil media and different pipe diameter conditions is carried out.The results show that under the same blasting conditions,as the pipe diameter increases,the dynamic stress of the pipe increases,and the peak surface vibration velocity decreases.The dynamic stress of the fine sand and the peak surface vibration velocity are the smallest,which has a good shock absorption effect on the pipeline.Therefore,in the project,fine sand is generally selected as the material for pipeline backfill.