Paper contribution

Weathering impact on the long-term stability of weak rocks

Bojan Janevski; Milorad Jovanovski

Proceedings
EUROCK 2026
Pages
151-156
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

Weathering processes and prolonged atmospheric exposure critically influence the mechanical properties of weak metamorphic rocks, notably reducing their structural integrity and heightening the risk of slope failure. This comprehensive study focuses on the effects of weathering on schists and phyllites along the A2 motorway in Macedonia. Methodologically, the research integrates detailed field surveys, laboratory testing, and slope stability assessments to quantify changes in key geotechnical parameters, including uniaxial compressive strength and the geological strength index, as a function of exposure duration. The findings reveal a significant deterioration in strength characteristics attributable to progressive mineral decomposition, fissuring, and disintegration driven by climatic factors. Empirical data indicate that slopes subjected to extended weathering exhibit increased incidences of shallow landslides and surface instabilities, which correlate strongly with reductions in UCS and GSI values. Graphical models were developed to illustrate the temporal trends of strength degradation, providing valuable insights for predictive assessments. The study underscores the importance of incorporating weathering effects into geotechnical design considerations, especially for long-term infrastructure projects situated on weak rock masses. Recommendations emphasise the necessity for ongoing monitoring, proactive stabilisation measures, and the integration of degradation factors into slope stability analyses to mitigate potential geohazards effectively.

Contributors

Authors

  1. Bojan Janevski Civil Engineering Institute “Macedonia”, Skopje, Macedonia ORCID 0000-0002-3767-5840
  2. Milorad Jovanovski University Ss. Cyril and Methodius, Skopje, Macedonia ORCID 0000-0002-6261-3721

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References

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