Monitoring of thermal and mechanical behavior of the access road to Salluit airport

By : Dejan Grabundzija

15/10/2013

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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)

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2. Context Geology

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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

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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)

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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)

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3. Mitigation

Figure 6 : Typical cross section of the rebuilt road (Ministère des transports du Québec/Génivar)

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3. Mitigation

Thermal drain

Figure 7 : Thermal drain installation

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3. Mitigation Better drainage

Figure 8 : Installation of an additional culvert

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3. Mitigation

Thermal drain

Figure 7 : Thermal drain installation

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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

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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

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3. Monitoring

Thermistors (initial data, summer 2012)

Figure 12 : Interpolation results of the initial temperatures (October 2012)

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3. Monitoring

Inclinometers

- 3 vertical inclinometers

- 2 horizontal inclinometers

Figure 11 : Inclinometer tube locations

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3. Monitoring

Inclinometers (results after 1 year)

Figure 11 : Inclinometer tube locations

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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

Thank you to our partners and collaborators