DEFORMATION CHARACTERISTICS OF PIPELINE IN MINING SUBSIDENCE AREAS BASED ON STRAIN

摘要

The mechanical model of oil and gas pipeline in mining subsidence areas is proposed according to the characteristics of mining areas and properties of pipe material, and the effects of subsidence imposed on pipeline are divided into soil creeping, local pipe span, free pipe span, and sudden soil subsidence respectively. The mechanical equations of four states are provided based on strain and Ramberg-Osgoods' stress-strain relationship, and the direct search method with Newton-Raphson method is used for the solution. Under the condition of different wall thickness (WT), outside diameter (OD) and buried depth, numerical calculation analyzes the deformation characteristics of the strain subject to the change in length of the span or subsidence. It shows that WT of pipe exerts the greatest impact than others, and the influence of buried depth is larger than OD except the state of soil creeping. In addition, a conclusion can be drawn that the application of strain-based design gives full play to the advantage of self-bearing ability, and the allowable length of subsidence imposed on pipeline is increased.