Sample Disturbance of Onsøy Clay Due to Gas Exsolution

  • Shaoli Yang
  • Tom Lunne
  • Gulin Yetginer
Conference paper


High quality block clay samples at Onsøy were obtained by using the Sherbrooke sampler. Pore water with various degrees of gas dissolved were introduced to soil specimen under a back pressure simulating 1500 m water depth. Then total stresses were released, resulting in gas coming out of solution before trimming samples for advanced tests. Results from both Triaxial compression tests (CAUC) and Direct simple shear tests (DSS) showed that sample disturbance is increasing due to gas exsolution up to η = 20% and there is less increase in effects on undrained shear strength for η = 20 to 67%. Δe/ei and anisotropy ratio indicate that sample disturbance due to gas exsolution has more influence on DSS and CRSC tests than on CAUC tests. CRSC tests showed that preconsolidation stress is decreasing with increasing degree of gas saturation. Tube sampling disturbance of onsøy clay from previous study is discussed and compared with disturbance due to gas coming out of solution.


Gas exsolution Undrained shear strength Sample disturbance Degree of gas saturation 



The authors would like to acknowledge constructive discussions with NGI colleagues and the support from the Norwegian Deepwater Programme - Seabed Project, as represented by Statoil. The Norwegian Research Council has also given financial support through the Norwegian Geotest Site Project where Onsøy is one of the sites being developed as part a large infrastructure facility for future research related to geotechnical engineering.


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Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Norwegian Geotechnical InstituteOsloNorway
  2. 2.Statoil ASAStavangerNorway

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