Evidences of the Effects of Free Gas on the Hydro-mechanical Behaviour of Peat

  • C. JommiEmail author
  • S. Muraro
  • E. Trivellato
  • C. Zwanenburg
Conference paper
Part of the Springer Series in Geomechanics and Geoengineering book series (SSGG)


Peats are soils containing a significant component of organic matter. Biochemical degradation of this fraction generates gases such as CO2, H2S and CH4, which tend to saturate the pore water eventually resulting in exsolution and expansion. The effects of these gases on the hydro-mechanical behaviour of peats are under investigation at Delft University of Technology. The results of a series of triaxial tests are discussed, in which gas was exsolved under controlled conditions by flushing natural samples with carbonated water, and undrained isotropic unloading and shear were performed. A significant reduction in the effective stress acting on the soil skeleton was observed during undrained unloading due to gas exsolution. However, different stages were observed in time, which appear to be ruled by the very high compressibility of peat. The mechanical response upon shearing is dominated as well by the ratio between the compressibility of the fluid and the soil skeleton. Although the ultimate strength does not differ much between the samples tested, the mobilised shear strength for a given axial strain does, which has to be accounted for cautiously in the choice for an operative shear strength.


Volumetric Strain Triaxial Test Pore Fluid Peat Layer Peat Sample 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Acharya MP, Hendry MT, Edwards T (2015) A case study of the long-term deformation of peat beneath an embankment structure. In: Manzanal D, Sfriso AO (eds) Proceedings of the 15th Pan-American conference on soil mechanics and geotechnical engineering, pp 438–445. doi: 10.3233/978-1-61499-603-3-438
  2. Amaratunga A, Grozic JLH (2009) On the undrained unloading behaviour of gassy sands. Can Geotech J 46(11):1267–1276. doi: 10.1139/T09-056 CrossRefGoogle Scholar
  3. Baird AJ, Waldron S (2003) Shallow horizontal groundwater flow in peatlands is reduced by bacteriogenic gas production. Geophys Res Lett 30(20). doi: 10.1029/2003GL018233
  4. Kellner E, Waddington JM, Price JS (2005) Dynamics of biogenic gas bubbles in peat: potential effects on water storage and peat deformation. Water Resour Res 41(8). doi: 10.1029/2004WR003732
  5. Lunne T, Berre T, Strandvik S, Andersen KH, Tjelta TI (2001) Deepwater sample disturbance due to stress relief. International conference on Geotechnical, geological and geophysical properties of deepwater sediments. Houston, TX, pp 64–85Google Scholar
  6. Nageswaran S (1983). Effects of gas bubbles on the sea-bed behaviour. Ph.D. thesis, Oxford UniversityGoogle Scholar
  7. Sander R (2015) Compilation of Henry’s law constants (version 4.0) for water as solvent. Atmos Chem Phys 15:4399–4981. doi: 10.5194/acp-15-4399-2015
  8. Sills GC, Wheeler SJ, Thomas SD, Gardner TN (1991) Behaviour of offshore soils containing gas bubbles. Géotechnique 41(2):227–241. doi: 10.1680/geot.1991.41.2.227 CrossRefGoogle Scholar
  9. Skempton AW (1954) The pore pressure coefficients A and B. Géotechnique 4(4):143–147. doi: 10.1680/geot.1954.4.4.143 CrossRefGoogle Scholar
  10. Skempton AW, Petley J (1970) Ignition loss and other properties of peats and clays from Avonmouth, King’s Lynn and Cranberry Moss. Géotechnique 20(4):343–356. doi: 10.1680/geot.1970.20.4.343 CrossRefGoogle Scholar
  11. Sobkowicz JC (1982) The mechanics of gassy sediments. Ph.D. thesis, Civil Engineering Department, University of Alberta, Edmonton, AltaGoogle Scholar
  12. Sobkowicz JC, Morgenstern NR (1984) The undrained equilibrium behaviour of gassy sediments. Can Geotech J 21(3):439–448. doi: 10.1139/t84-048 CrossRefGoogle Scholar
  13. Sultan N, De Gennaro V, Puech A (2012) Mechanical behaviour of gas-charged marine plastic sediments. Géotechnique 62(9):751–766. doi: 10.1680/geot.12.OG.002 CrossRefGoogle Scholar
  14. Wheeler SJ (1988) A conceptual model for soils containing large gas bubbles. Géotechnique 38(3):389–397. doi: 10.1680/geot.1988.38.3.389 CrossRefGoogle Scholar
  15. Zwanenburg C (2013) Dikes on Peat: analysis of field trials. Internal report, DeltaresGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • C. Jommi
    • 1
    Email author
  • S. Muraro
    • 1
  • E. Trivellato
    • 1
    • 2
  • C. Zwanenburg
    • 3
  1. 1.Delft University of TechnologyDelftThe Netherlands
  2. 2.Laboratoire NavierÉcole Nationale des Ponts et ChausséesParisFrance
  3. 3.DeltaresDelftThe Netherlands

Personalised recommendations