Geomechanical behaviour of gassy soils and implications for submarine slope stability - a literature analysis

Journal
Geological Society, London, Special Publications  
Start Page
277
End Page
288
Citation
Geological Society, London, Special Publications, 500, 277-288, 2020
Publisher DOI
10.1144/SP500-2019-149
Scopus ID
2-s2.0-85087377673
Publisher
Scottish Acad. Press
Submarine slope failures pose a direct threat to seafloor installations and coastal communities. Here, we evaluate the influence of free gas on the soil's shear strength and submarine slope failures in areas with gassy soils based on an extensive literature review. We identify two potential destabilization mechanisms: gas bubbles in the pore space lead to a reduced shear strength of the soil and/or gas induces excess pore pressures that consequently reduce the effective stress in the soil. Our evaluation of the reported mechanical and hydraulic behaviour of gassy sediments indicates that the unfavourable impact of entrapped gas on a soil's shearing resistance is not sufficient to trigger large scale slope failures. Liquefaction failure due to high gas pressures is, however, a viable scenario in coarse-grained soils. Transferring the gas influence on the soil mechanical behaviour to constitutive models is identified as the most important prerequisite for a successful future analysis of slope stability.
Subjects
Stability of submarine slopes
DDC Class
550: Geowissenschaften