Rock mass failure of foliated rock at the nuclear waste disposal site in Olkiluoto, Western Finland

Topias Siren, Johannes Suikkanen, Jesse Ström

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


In Finland and Sweden, the geological nuclear waste disposal is heading for the implementation phase in the next ten years or so. In the disposal concept, the knowledge of the rock mass strength and in situ rock stresses are important for long-term safety analyses. The rock mass strength of the nuclear waste disposal site in Olkiluoto, Western Finland, was researched as a part of Posiva’s Spalling Experiment (POSE). The POSE experiment was conducted as an in situ rock mass strength test that revealed the rock mass failure in Olkiluoto being governed by fracture growth at lithological borders instead of spalling type of failure commonly encountered in sparely fractured crystalline rock conditions. Based on the POSE experiment results, a structurally controlled failure is distinguished as a new rock mass failure mechanism. A back-calculation campaign was established to study the new rock failure mechanism with multiple modeling techniques, of which the results of fracture mechanics code FRACOD simulations are presented in this paper. Fracture Mechanics is able to mimic failure conditions, however after excessive calibration.
Original languageEnglish
Title of host publication2017 YSRM Young Scholars' Symposium on Rock Mechanics
Subtitle of host publicationProceedings of
Place of PublicationKorea
Number of pages4
ISBN (Electronic)9791156103158
Publication statusPublished - 11 May 2017
MoE publication typeA4 Article in a conference publication
EventYoung Scholars' Symposium on Rock Mechanics - Jeju, Korea, Republic of
Duration: 10 May 201713 May 2017
Conference number: 4


ConferenceYoung Scholars' Symposium on Rock Mechanics
Abbreviated titleYSRM
CountryKorea, Republic of


  • 2D modelling
  • Anisotrophy
  • Back-analysis
  • Failure Mechanism
  • Foliated rock
  • Rock mass failure

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