Design strain calculation model for oil and gas pipelines subject to geological hazards

To meet the engineering requirements of two new pipeline design methods (i.e., the strain-based design method and the reliability-based design method), the common geological hazards (e.g. faults, mining subsidence, frozen soil and landslide) encountered by oil and gas pipelines were summarized and their soil displacement forms were classified. Then, a simplified geological hazard displacement model and a pipeline design strain calculation model were proposed by generalizing the mechanics model based on finite element analysis and the empirical formula for calculating the design strain of pipelines under the effect of faults to the other geological hazards, e.g. mining subsidence, frozen soil and landslide. In this model, the displacement of the geological hazards is regarded as the analog of fault displacement in vertical or horizontal plane. And as a result, the calculation method for pipeline strain subject to other geological hazards was derived. With the advantages of high accuracy, high efficiency and wide applicability, the proposed method is especially applicable to the reliability-based design of oil and gas pipelines under the effect of various geological hazards.