Monitoring of thermal and mechanical behavior of the access road to Salluit airport
By : Dejan Grabundzija
15/10/2013 1. Localisation
Salluit, Québec
- Salluit (62° 14' N, 75° 38' O) is located north of the Ungava peninsula, in the Nunavik region
- Salluit is the fourth most populated village in northern Quebec with 1347 inhabitants, after Kuujjuaq (2375) Inukjuak (1812) and Puvirnituq (1692 )
- The villages airport is an important lifeline, especially during winter months
Figure 1 : Permafrost zones (Ressources naturelles Canada)
1. Localisation 2 / 17 2. Context Geology
1. Localisation 3 / 17 2. Context
Structural problems of the old road
• Evidence of permafrost deterioration under the road
• Danger of landslides
• The road was rebuilt in the summer of 2012
Figure 3 : Road deterioration summer 2012
2. Context 4 / 17 3. Mitigation
• Thermal drain:
- Geomembrane that allows air circulation under the embankment
- Cold air enters the lower part of the embankment and the rising hotter air is evacuated at the top
Figure 4: Thermal drain « Terradrain » (Jorgensen et coll., 2008)
3. Mitigation 5 / 17 3. Mitigation
• Thermal drain:
- Geomembrane that allows air circulation under the embankment
- Cold air enters the lower part of the embankment and the rising hotter air is evacuated at the top
Figure 5: Schematic of a thermal drain system (Doré et coll., 2007)
3. Mitigation 6 / 17 3. Mitigation
Figure 6 : Typical cross section of the rebuilt road (Ministère des transports du Québec/Génivar)
3. Mitigation 7 / 17 3. Mitigation
Thermal drain
Figure 7 : Thermal drain installation
3. Mitigation 8 / 17
3. Mitigation Better drainage
Figure 8 : Installation of an additional culvert
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Thermal drain
Figure 7 : Thermal drain installation
2. Context 2 / 10 3. Monitoring
Thermistors
- 2 series of 50 vertical thermistors
- 2 series of 25 horizontal thermistors
- 12 thermistors inside the thermal drain geomembrane
Figure 10: Thermistor distribution along the road
3. Mitigation 11 / 17 3. Monitoring
Thermistors
- 2 series of 50 vertical thermistors
- 2 series of 25 horizontal thermistors
- 12 thermistors inside the thermal drain geomembrane Figure 11 : One set of vertical thermistors
3. Mitigation 12 / 17 3. Monitoring
Thermistors (initial data, summer 2012)
Figure 12 : Interpolation results of the initial temperatures (October 2012)
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Inclinometers
- 3 vertical inclinometers
- 2 horizontal inclinometers
Figure 11 : Inclinometer tube locations
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Inclinometers (results after 1 year)
Figure 11 : Inclinometer tube locations
3. Mitigation 15 / 17 4. Things to come
- Analysis of thermal regimes (spatial and temporal sequences) of two cross sections of the embankment (vertical thermistor series) in order to study the performance of the thermal drain
- Relation between the air temperature outside and inside the thermal drain (thermistors inside the geomembrane)
- Cost/benefit analysis of the thermal drain mitigation technique
- Continued temperature / deformation monitoring
4. Things to come 5 / 17 Thank you to our partners and collaborators