Pipeline and Underground Structure Monitoring
The long length, large investments, sometimes high risk of human and environmental impact along with difficult access conditions, make an automated monitoring system desirable for pipelines, tunnels and mines. Unlike for above-ground structures, earthquake-generated inertia forces are not the main cause of damage to these structures – damage is closely related to ground motion. For this purpose, the seismic ground response can be roughly subdivided into two broad classes:
- Induced deformation effects, such as ground failure due to fault ruptures, slope instability, liquefaction;
- Ground shaking, associated to dynamic longitudinal or shear strains in the structure.
Given the spatial extension of the area covered by pipelines and underground structures, the objectives are to monitor both types of earthquake ground response.
Measurement of ground motion can be realized along pipelines, over oil and gas infrastructure in relation to landslip, river crossings, tectonic hazard zones, underground oil and gas storage facilities and mining areas using state-of-the-art techniques.
The main parameters to be measured are:
- Ground motion, mostly using strong motion instruments.
- Permanent ground displacement, using inclinometers, tiltmeters, extensometers, crack meters, and topographic or GPS measurements.
- Pipeline Temperature, there are several methods and sensors.
- Pipeline Strain, mostly with strain meters.
- Pipeline Strain and bending, mostly with strain meters and fiber optic.
- Leakage detection, with pressure meters located inside the pipeline.
- Third-party intrusion detection, using satellite images.
Other key elements are the pumping stations which, when damaged by an earthquake, render the whole system inoperable. In a seismic area, at least one strong motion instrument should be located at each pumping station.