Presentation given at ANZ GEO2023 at Cairns, QLD. Presentation considers: What are the main impacts of climate change? What does climate change mean for geotechnical engineers? What can we do in our works? What are the challenges?

1. Long-term geotechnical
impacts of climate change on
projects
Dr Chris Bridges
Technical Director – Ground and
Underground Engineering

2. 2
Contents
• What are the main impacts of climate change?
• What does climate change mean for us?
• What can we do?
• What are the challenges?

3. What are the main impacts
of climate change?

4. 4
en.wikipedia.org
Temperature
Steemit.com
Precipitation
theguardian.com
Flood
Temperature
Flood
Precipitation

5. What does climate change
mean for us?

6. 6
• Drought –
• desiccation / shrink-swell
• Decreased precipitation
• Groundwater level drop
en.wikipedia.org
Temperature

7. 7
• Drought –
• desiccation / shrink-swell
• Decreased / increased precipitation
• Groundwater level drop
• Wildfire - hydrophobic
• Reduced vegetation
• Erosion
en.wikipedia.org
Temperature

8. 8
• Drought –
• desiccation / shrink-swell
• Decreased / increased precipitation
• Groundwater level drop
• Wildfire - hydrophobic
• Reduced vegetation
• Erosion
• Permafrost
• Rockfall
en.wikipedia.org
Temperature

9. 9
• Groundwater level rise
• Uplift
• Increase in water pressure on
structures
• Slope failures
Steemit.com
Precipitation
Wu et al, 2020

10. 10
• Groundwater level rise
• Uplift
• Increase in water pressure on
structures
• Slope failures
• Surface runoff - erosion
Steemit.com
Precipitation

11. 11
theguardian.com
Flood
Tropical cyclones and climate change (2010) Thomas R. Knutson, John L. McBride ,
Johnny Chan , Kerry Emanuel, Greg Holland , Chris Landsea , Isaac Held , James P.
Kossin, A. K. Srivastava and Masato Sugi

12. 12
• Coastal / riverbank erosion
• Earthwork & structural failures
• Scour
theguardian.com
Flood

13. What can we do?

14. 14
Design impacts
New structures
Foundations
• Design for higher / lower long-term gwl
• Higher loads
• Scour
Slopes & walls
• Erosion protection
• Higher/lower gwl
• Drainage

15. 15
Design impacts
Existing structures
• Shorter design life
• Higher maintenance costs

16. 16
Design impacts
Existing structures
• Shorter design life
• Higher maintenance costs
• Landslides
• Retrofitting -
• Additional drainage
• Erosion protection

17. What are the challenges?

18. 18
Challenges
Standards & contract conditions
• Retrospective and based on precedence
• Slow to change
• Environmental changes may be more rapid
than our standards and specifications can keep
up with
• Long-term material performance
• Risk allocation
Construction
• Higher temperatures
• Intense, short-duration rain events
• Earthworks construction
• Haul roads

19. 19
Challenges
Sustainability
• Heavier designs to address climate impacts
(resilience) using more resources, e.g.
• Wider embankments
• More erosion protection
• Larger piles to resist scour
• Piles favoured over shallow foundations
• Higher maintenance costs
• Retrofitting of existing structures
• New materials
Climate modelling
• Uncertain
• Dependent on mitigations undertaken
• Need data to provide better long-term
forecasting and solutions

20. 20
Climate impacts on soil
moisture, erosion and
performance

21. 21
Summary
Contract
Documents /
Standards
Rapidly
changing
climate
Design life
Heavier
structures
Sustainability
Data driven
solutions
New
materials

22. Thank you