8. Notations

total strain tensor

Tensor of the deformations of natural creep

elastic deformation tensor

spherical part of the natural creep strain tensor

reversible spherical part of the natural creep strain tensor

irreversible spherical part of the natural creep deformation tensor

Deviatoric part of the tensor of natural creep deformations

reversible deviatoric part of the tensor of natural creep deformations (contribution of absorbed water)

irreversible deviatory part of the tensor of the deformations of natural creep (contribution of free water)

total stress tensor

spherical part of the stress tensor

deviatoric part of the stress tensor

internal relative humidity

elastic modulus of stiffness at expansion

apparent stiffness associated with the skeleton formed by hydrate blocks at the mesoscopic scale

apparent stiffness intrinsically associated with hydrates at the microscopic scale

stiffness associated with the capacity of adsorbed water to transmit loads (load bearing water)

elastic shear modulus

apparent viscosity associated with the mechanism of inter-lamellar diffusion

apparent viscosity associated with the diffusion mechanism within the capillary porosity

viscosity of free water.

viscosity associated with water adsorbed by hydrate sheets

\({\eta }^{\mathit{fd}}\) viscosity of desiccation creep

\(\chi\) creep-damage coupling coefficient

designate respectively a scalar, a vector and a tensor of order 2.

denote respectively the value of the quantity x at time

, at the time

and the variation of

during the interval

.