Failure Analysis Of Oil And Gas Pipeline In Frozen Area

Frozen soil is a common soil type in foundation engineering construction. For oil and gas pipeline construction, it is inevitable to cross the frozen soil area. In normally, the frozen can be divided into permafrost, perennially frozen soil and seasonal frozen soil. The main differences include the freezing time and phase change process, and the physical and chemical properties. The frozen soil in the area corresponding pipe network facilities will produce certain impact and destruction. Therefore, it is necessary to do some research and analysis of the pipeline facilities in frozen soil area for higher level with pipeline design, construction and maintenance.This paper mainly analyzed the frost damage problem and the effect of pipeline engineering to frozen soil regions on the basis of the theory of frozen soil, frozen soil mechanics and pipeline mechanics research.1) The analysis based on the existing research of the frozen soil mechanics. The paper analyzed the moisture migration and its influencing factors in soil heave and freezing process and the frozen mechanism and cooling structure of soil, a detailed analysis of the influencing factors of frost heave was summarized, and the anisotropy of freezing expansion force calculation and frost heave model.2) The basic characteristics of the melting and consolidation of the soil and its influence factors are analyzed, and the experience method is used to forecast the thawing settlement of the frozen soil. Different consolidation theory has its own emphasis and research scope, so there is varied in the calculation form.3) The interaction of soil-pipe in frozen soil regions was analyzed by ANSYS with the method of finite element. The influence of oil temperature on frozen soil environment is given. Existing research mainly focus on two-dimensional temperature field distribution analysis, and considering the pipeline temperature cycle changes seasonal and the overall operational life. This is the first time attempt to analysis the distribution of the temperature field of soil around pipeline in the three-dimensional field in different depth of ground and oil temperature changes in pipeline axial at the same time.4) The paper according to the detailed survey data of the China-Russian oil and gas pipeline section AE, the paper analyzed frozen and thawing of the permafrost and seasonal frozen soil, evaluated the frozen soil of the pipeline risk assessment, given the corresponding treatment measures and construction suggestion. Although the oil pipeline has been put into operation for many years, the contemplate of design and construction of pipeline design and construction are of great reference value and practical significance to the pipeline exploration, design and construction of the pipeline in the future.