Mechanical Response And Safety Evaluation Of Buried Pipeline Crossing Landslide

China is one of the world’s largest energy consumers,so its energy transportation system is crucial.In addition to the common modes of transportation,such as road,rail and water,transporting oil and natural gas over long distances is economical and safe.The buried pipelines in China have a long length and pass through complex geological regions,which are prone to natural disasters such as landslides and other damage such as pipeline movement and buckling,which will threaten the safe operation of pipelines.Based on the relevant information of landslide cases in Huanjiang County,Guangxi,this paper adopts Midas modeling and FLAC3 D analysis method to study the mechanical response of buried pipelines under the action of landslides of different landslide scales,as well as whether the pipelines can operate safely and other important research content,which is of great significance to the design of planned pipeline routes and the safety evaluation of pipelines.The main research contents include the following aspects:(1)Summarize the geological disasters occurring along the buried pipeline in a region of Guangxi,describe the natural and geographical conditions along the route,and introduce the pipeline profiles along the route,providing the parameter basis for the numerical simulation in the following paper.(2)Introduce the common theoretical calculation method of pipeline crossing landslide,establish different landslide models based on the control of different variables,analyze the slope stability of the theoretical model,explore the mechanical response law of the three single factors,namely the displacement of the landslide,the width and the thickness of the landslide area,and obtain the positive correlation between the equivalent stress extreme value of the buried pipeline and the three factors.Then determine the relative sensitivity of each factor by orthogonal test.Landslide width is the most sensitive,followed by landslide displacement and landslide area thickness.The pipeline companies should pay more attention to the influence of landslide width on pipeline safety.(3)Establish a simple critical criterion based on landslide displacement and landslide width to obtain the landslide displacement critical values of pipeline failure in different landslide widths and the landslide width critical values of pipeline failure in different landslide dislocations.In order to combine the landslide scale and working environment,conduct a pipeline safety evaluation of similar landslide cases around Huanjiang County,Guangxi.(4)The numerical model of No.2 landslide in Luoyang Town is established to analyze the slope stability and pipeline safety state before and after landslide engineering case treatment.The critical criterion based on landslide displacement and landslide width and the numerical simulation method are used respectively to determine the safety state of the pipeline.The predicted results and the numerical simulation results are consistent with the actual situation,and no yield failure occurs,which is consistent with the fact of pipeline safety,which verifies the validity of the conclusions.It provides theoretical support for safety evaluation,monitoring and early warning of pipelines in relevant areas under the action of landslides.The stability coefficient of the treated slope under the most unfavorable working condition is1.191,which reaches the stipulated standard 1.1 of the slope.The treatment project can achieve the purpose of permanent protection of the slope soil and a buried pipeline.