Stress And Deformation Analysis And Remote Monitoring Of Buried Pipeline In Pied Coal Seam

Mine subsidence area is likely to cause the surface subsidence deformation, crazing, collapse and other geological disasters.If pipeline engineering needs through surface movement deformation area, it may cause buried oil and gas pipeline in a wide range of deformation and suspending, even to the detriment of safety. In this dissertaion, research have been done on the characteristics of pipeline deformation and stress change, failure criteria and pipeline remote monitoring when pipeline subjected to mine subsidence.The research is conducive to prevent mining disasters and evaluate threat to pipeline.It can provide some theoretical bases and technical references for the pipeline engineering design, construction and management of maintenance.Firstly, the deformation characteristics of buried pipelines on mine subsidence area are studied under the influence of surface movement.Axial interaction between the soil and pipe through mine subsidence area is investigated in the condition of the flexible criterion. The pipe deformation curve is expressed by surface subsidence and transverse deformation. Then combining with the probability function integration method, large deflection beam theory, the theory of elastic foundation and pipe soil bilinear theory, the pipe of physical elongation and coordination between the geometric deformation equation have been given by analyzing the characteristics of pipeline stress in mining area.Through the analysis of a example, the mechanical characteristics of pipe in mining subsidence area have been drawn.Secondly, this study establish finite element simulation models of the pipeline in the coal mining process and finite element simulation models of suspended pipeline in the mined collapse area. The mechanical behavior and deformation evolution regularity of pipe are analyzed under different mining conditions (different angle between line direction and working face advancing direction, different tilt angle coal seam, different buried depth and different inner pressure) by the influences of coal mining research.The correctness of suspended pipeline simulation calculation model is verified by suspended pipeline test, and have analyzed the mechanical state of the suspended pipeline in mined collapse. Suspended pipeline is studied based on the theory of stress and of strain. The allowable suspended length and the limit suspended length are determined based on strain failure. The above analysis results showed that, the angle of90°between pipeline laying direction and coal mining working face advancing direction is optimal in the mining subsidence pipeline engineering; The influence on pipeline which is in mining process of flat coal seam is larger than the big angle of coal seam mining process; It is advisable for pipeline in mining process with shallow buried, and is a appropriate choose to use low friction backfill material in order to reduce the tube axial friction with the soil function; when pipeline is under the suspended state in mined collapse, it has a real help to study the pipe sinking dangling mechanics behavior and the safety status analysis from the perspective of strain analysis;The limiting strain2%as pipeline suspended failure criterion is rational.Finally, a feasible monitoring method is put forward in view of the Xinjiang LuCaoGou mined coal geological characteristics, combined with the potential harm of Shan-Wu pipeline in the actual situation of coal mined area. Monitoring data analysis show that this remote monitoring method can accurately monitor the change characteristics and variation of pipe stress and strain on the mined area surface movement, for provideing a economic feasible solution in security maintenance of long-distance pipeline.