Abstract
Pipelines in Western Canada cross numerous areas of active or potential landslides that pose a threat to pipeline integrity. The lines with the highest risk of landslides have been surveyed since 1994 with inertial/caliper in-line inspection tools that provide complete information on the pipe centreline shape, bending strain, position on maps as well as movement between inspections. These tools also record caliper measurements of pipe wall deformations which allows for detection of wrinkles and other anomalies that develop as the result of the pipe to soil interaction in landslide areas.
This paper demonstrates advantages of the in-line geometry survey over traditional monitoring methods such as geotechnical surveillance or installation of strain gauges on the pipe. The major benefit is providing data for the entire line, not just selected areas of concern. The experience with using this technology revealed that pipeline movement can occur in areas that were not suspected of being subject to landslides, and were not identified by traditional geotechnical patrols. Another important advantage of an in-line geometry survey is the direct measurement of the cumulative effects of landslides on the pipeline integrity since the construction. This allows for accurate identification, sizing and location with Global Positioning System (GPS) of the most vulnerable points in the line in terms of large bending strains and pipe wall deformations.
