Geotechnical Risk Assessment: Estimating Slope Failure Probability

Abstract

The Transcanada Pipelines Ltd. (TCPL)mainline system carries natural gas from the Alberta/Saskatchewan border to delivery points near the Quebec/Vermont border. The system contains pipelines that traverse approximately 4,000 kilometres (2,500 miles) of terrain and delivers about 2,900 Bcf of gas per year. As part of the integrity program this system has been subjected to a geotechnical hazard identification and assessment program over the last several years. The geotechnical hazard assessment process has identified hazardous sites and specific studies at these sites have been undertaken. TCPL has recently begun a transition from performing Hazard Management to an overall Risk Management approach for pipeline integrity. As part of this process TCPL required that a geotechnical risk methodology be developed to analyze the risk posed to the pipeline due to landslides. Therefore a new landslide failure probability estimation process was developed to complete this program.