TY - GEN
T1 - Evidences of the effects of free gas on the hydro-mechanical behaviour of peat
AU - Jommi, C.
AU - Muraro, S.
AU - Trivellato, E.
AU - Zwanenburg, C.
PY - 2017
Y1 - 2017
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85011391946&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-52773-4_12
DO - 10.1007/978-3-319-52773-4_12
M3 - Conference contribution
AN - SCOPUS:85011391946
SN - 9783319527727
T3 - Springer Series in Geomechanics and Geoengineering
SP - 112
EP - 119
BT - Advances in Laboratory Testing and Modelling of Soils and Shales, ATMSS 2017
PB - Springer
T2 - International Workshop on Advances in Laboratory Testing and Modelling of Soils and Shales, ATMSS 2017
Y2 - 18 January 2017 through 20 January 2017
ER -