Study On Deformation And Damage Of Pipeline And Prevention In Goaf Of Chashan Coal Mine In Shaoguan

With the large demand for petroleum and natural gas,the construction of long-distance pipelines in China has entered a peak period.Because gas pipeline is a linear project with long distance and wide distribution,it is inevitable to pass through some goaf subsidence areas and various complex geological areas in the process of burying.When the gas pipeline passes through the goaf,if the goaf surface moves and deforms,the pipeline will deform with the surface subsidence.Once the maximum allowable deformation value of the pipeline is exceeded,the pipeline will gradually void with the soil,causing the pipeline to hang and even break,which will pose a great threat to the safety of the pipeline.At present,the research on the safety of pipeline in goaf is mainly focused on the gently inclined goaf.Because of the steep inclination of coal seam,the geological conditions are more complex,which leads to less theoretical research in this area.Therefore,it is of great significance for the safe operation of pipelines to study the law of pipe-soil interaction and deformation properties in the goaf of steeply inclined coal seam and find out the appropriate preventive measures.This study takes the proposed pipeline of Qianjiang-Shaoguan section which affected by steeply inclined goaf in Chashan mining area as the research background.Based on the data of the study area and the existing research results,the influence of steeply inclined goaf on the pipeline were studied from the completion of mining and the mining process.This paper analysed the influence of surface deformation and movement of goaf on gas pipeline,gave a preliminary evaluation method of pipeline safety,and used probability integral method to predict and evaluate pipeline safety in steeply inclined goaf site.At the same time,the engineering geological conditions of No.10 coal seam in Chashan mining area were taken as the geological background.Based on the method of physical similarity simulation test and numerical simulation,the law of pipe-soil interaction and deformation properties in the goaf of steeply inclined coal seam were studied.By comparing and analyzing the vertical and horizontal displacements,strains and vertical stresses of pipe-soil in different stages,the following conclusions were drawn: The deformation law of pipeline and soil was roughly the same in the first and second stages of coal seam mining.In the third stage of coal seam mining,the deformation between pipe and soil was different and the difference increased gradually.Pipe and soil undergoes the process of synchronizationand voidage.Pipeline deformation is the most serious in the central and both ends of goaf,which is the key prevention area.Finally,according to the geological conditions of the study area,the corresponding prevention and control measures were put forward.Based on the influence of surface deformation and movement on gas pipeline and the law of pipe-soil deformation and failure,a monitoring method was proposed to master pipeline deformation through surface deformation.The grouting method was selected as the main scheme to control the goaf,and the numerical simulation analysis showed that the effect of grouting treatment of the goaf is remarkable.This method greatly improved the stability of goaf and was beneficial to pipeline construction.