Remediation of Pipelines Affected by Ground Movements
Lockey A., Young A.
Fixing Pipeline Problems Conference; Berlin; October 2012.
In-service pipelines affected by ground movement geohazards may experience loads that threaten their structural integrity. These geohazards can include landslides, subsidence and geological faults. Mitigation options normally considered during design include routing around the geohazard, and increasing the ability of the pipe to withstand the movement. Geohazards are not always identified during design, and can represent a threat to the integrity of operational pipelines. The mitigation options available for new pipelines would involve expensive re-route or re-lay projects for operational pipelines.
It is possible to extend the period of acceptable pipeline operation and reduce the risk from an existing geohazard. This is usually done by exposing the pipeline to relieve ground movement loads, and modifying the geometry of the pipeline trench to reduce the development of further loads. Soft trench fills are used to reduce the load transferred from the moving ground to the pipeline. These works can be implemented more cheaply and quickly than re-routing. This paper uses structural modelling to demonstrate the benefits of special trench designs and soft fills to pipeline integrity.