Performance of earthworks infrastructure

The performance and behaviour of earthworks (cuts, fills and retaining structures) impacted by landslides generated by the 2016 Mw 7.8 Kaikoura earthquake have been investigated by WSP consultants. The work, presented in four reports, provides case studies and recommendations for resilient design and construction of these earthworks.

The first report provides maps and summarises the extents of failures along the transport corridors affected by the earthquake. From this work, landslides of differing type and geological material were selected for more detailed investigation. Mason, D., and Brabhaharan, P. 2023(a). Kaikōura Earthquake-Induced Landscape Dynamics Research – Theme 6 – Stage 1 – Landslide inventory report. WSP report no. GER 2023/12. Wellington, NZ: WSP, 18 p.

Investigations carried out at case study sites are summarised in report 2. Investigations included engineering geological mapping, lidar survey, boreholes and sampling, downhole logging and geophysics, and laboratory testing. Mason, D., and Brabhaharan, P. 2023(b). Kaikōura Earthquake-Induced Landscape Dynamics Research – Theme 6 – Stage 2 – Site investigation report. WSP report no. GER 2023/13. Wellington, NZ: WSP, 202 p.

Analysis of selected landslides, to characterise the slope failure mechanisms and relate these to the observed impacts, is the subject of the third report. Engineering geological models were developed, numerical analyses undertaken, and the performance of design structures assessed. Mason, D., and Brabhaharan, P. 2023(c). Kaikōura Earthquake-Induced Landscape Dynamics Research – Theme 6 – Stage 3 – Assessment report. WSP report no. GER 2023/14. Wellington, NZ: WSP, 53 p

The fourth report discusses the failure mechanisms and damage and makes recommendations for resilience-based design approaches for infrastructure that could be incorporated into existing standards and guidelines, to enhance performance of these slopes. Mason, D., and Brabhaharan, P. 2023(d). Kaikōura Earthquake-Induced Landscape Dynamics Research – Theme 6 – Stage 4 – Recommendations for earthquake resilient design of earthworks slopes. WSP report no. GER 2023/15. Wellington, NZ: WSP, 48 p.