Large deformation model of landslide and pipeline induced by methane hydrate dissociation

PhD student (SA-Res)

Fanbao Cheng

Supervisors

Prof Weiguo Liu (Dalian University of Technology)	A/Prof Xiang Sun (Chinese Academy of Sciences)	Prof Yinghui Tian

Project Start Date: September, 2021

Project Details

Methane gas hydrate is a crystalline substance resembling ice, composed of methane gas and water. It primarily exists within the seabed sediment under conditions of low temperature and high pressure. When the temperature or pressure of the surrounding environment changes, its stability will be compromised, potentially triggering geological disasters such as collapse and submarine landslides, which can result in significant damage to drilling platforms and submarine pipelines. Moreover, hydrate dissociation leads to the release of free gas several times larger than its original volume. As a substantial amount of free gas infiltrates the soil, pore pressure increases, effective stress diminishes, and cohesion and cementation strength among soil particles decrease, ultimately resulting in pipeline displacement failure and submarine slope instability. This is a large deformation process with coupled thermo-hydro-mechanical-chemistry multiphysics. In this study, the Smoothed Particle Hydrodynamics method is employed to establish a coupled large deformation simulation framework, comprehensively considering factors such as effective stress, sediment strength degradation due to hydrate dissociation, and the hydrate phase transition heat. This framework offers valuable insights into predicting submarine landslides and pipeline damage arising from hydrate dissociation.