Optimum Design of Gas Transmission Infrastructures against Ground Movements
Proceedings Publication Date
As the needs for energy worldwide are continually increasing, the optimum engineering design of gas transmission infrastructures, such as onshore or offshore high-pressure gas pipelines, compressor stations, and LNG terminals is a fundamental step. Since the design should always be cost effective, the term “optimum” is used here to describe the balance between safety and economy. One of the key issues during the design of both pipelines and facilities is the potential ground movements due to various geohazards under static and seismic conditions, such as landslides, ground settlements, active faults, soil liquefaction, etc. According to the current state of practice, there exist various ways to treat potential ground movements. The simplest way is to avoid the problematic (in terms of ground movements) area(s) by rerouting the pipeline or relocating the facility. Since this is not always feasible (due to various technical and/or environmental constraints), the alternative way is to construct the pipeline and/or the facility within the problematic area. In the second case, the application of various mitigation/protection measures aiming to minimize the ground movements is a straightforward option. On the other hand, a more sophisticated treatment is to verify the pipeline and/or the facility against the expected ground movements (without any mitigation/protection measures), and check whether the developed distress (in terms of strains or stresses) is acceptable or not. It is evident that if the distress is proved to be excessive and inacceptable for the structure or infrastructure under examination, the application of mitigation/protection measures is the one and only solution. Since the engineer should check all feasible solutions depending on the circumstances, compare the associated risk and cost, and propose the optimum solution to the client, the current paper tries to shed some light on the very challenging and tricky issue of the design of gas transmission infrastructures against ground movements.