Elasto-viscoplastic constitutive model for time-dependent consolidation characteristics of methane hydrate-bearing sands
Elasto-viscoplastic constitutive model for time-dependent consolidation characteristics of methane hydrate-bearing sands
Methane gas production from methane hydrate reservoirs is expected to become a new technology for natural energy supplies. As an effective technology associated with the methane gas production, the depressurization method has been proposed, and several production tests employing depressurization have been achieved in recent years. Due to the accompanying changes in complex stress state during gas production, understanding and evaluating mechanical properties, assuming time-dependency of methane hydrate bearing sediments, is essential. In this study, an elasto-viscoplastic constitutive model that can simulate time-dependent behavior of methane hydrate bearing-sands was proposed based on the experimental results obtained by consolidation tests. Proposed constitutive model introduced the concept that irrecoverable strain was represented as the total of plastic strain and creep strain. The creep strain was described by introducing the logarithmic creep law. Creep parameters need to input depending on the magnitude of confining stress and stress rate. The proposed constitutive model can comprehensively predict time-dependent characteristics, such as stress rate dependent behavior and creep behavior, during consolidation.
K. Nakashima; Yukio Nakata
9th International Congress on Environmental Geotechnics (ICEG2023)
Geo-Energy
https://doi.org/10.53243/ICEG2023-15
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