Study On The Mechanism And Prevention Of Damage To Buried Pipelines During Mining

With the rapid development of pipeline transportation and the continuous expansion of the area of coal mining areas in China,the contradiction between pipeline coal pressing and coal mining in mining areas has become increasingly serious.This study takes the sub-high pressure gas pipeline protection in the 630 mining area of Tangkou Coal Industry as the engineering background,explores the mining damage response mechanism and control measures of buried pipelines,and aims to solve the contradiction that the mining of Tangkou 630 mining area affects the gas pipeline,and protect the gas pipeline.The operation safety of overlying gas pipelines can be solved,and the problem of coal mining under the pipelines can be solved.Prediction by the probability integral method,The soil deformation around the pipe and the stress-strain of the pipe were studied by calculation and numerical simulation methods,and a pipe deformation control method suitable for the characteristics of the research area was proposed.The specific research content of this thesis is as follows:(1)In view of the variable angle between the mining direction of the working face and the direction of the pipeline in the study area,the numerical simulation was carried out by using the probability integral method and the constructed numerical model,and the relationship between the mining direction of the working face and the mechanical response of the pipeline was obtained.The test results show that as the angle between the mining direction of the working face and the direction of the pipeline increases,the stress and strain of the pipeline decrease first and then increase.The stress and strain of the pipeline are the smallest when the angle between the mining direction and the pipeline is 15 degrees and 30 degrees,respectively,and the stress and strain of the pipeline are the largest when the angle between the mining direction and the pipeline is 90 degrees.When the mining direction of the working face is parallel and perpendicular to the pipeline,it is the most unfavorable mining direction,and the angle between the mining direction and the pipeline is 15 and 30 degrees,which is better mining direction of the underground working face.(2)In view of the complex phenomenon of pipeline embedding conditions,the three factors of embedding method,filling soil properties and pipeline embedding depth were explored by numerical simulation method.The compressive strain value is the smallest,and the trench bottom burial is set as the most unfavorable burial method;the stress-strain value of the pipeline buried in soft soil is smaller;the shallower the buried depth,the smaller the stress-strain value of the pipeline.Pipelines in the mining area should be buried shallowly under soft soil as far as possible,and avoid laying pipelines at the bottom of the ditch.(3)According to the strain-based pipeline failure criterion,the surface deformation value when the axial strain of the pipeline reaches the allowable strain is used as the failure criterion of the pipeline,and the critical value of the surface deformation of the pipeline damage in the study area is obtained.And according to the critical value of surface deformation,the actual mining and continuous mining plan in the study area are evaluated to pipeline safety,which provides a theoretical basis for subsequent pipeline prevention and control.(4)Combined with the comprehensive analysis of the engineering geological conditions and pipeline conditions in the study area,the above-ground and underground coordinated control measures suitable for the study area are proposed.Replan the working face underground,so that the mining direction of the working face is as oblique as possible to the pipeline at 15-30 degrees,and at the same time coordinate the mining of the working face to reduce the lateral displacement and deformation of the pipeline;Monitoring,and taking measures such as pipe trench excavation to improve the pipeline embedding conditions to improve the deformation resistance and safety of the pipeline.There are 60 figures,15 tables and 75 references in this thesis.