Abstract: Gas-hydrate-bearing soil is a special soil with hydrates filling in the pores of the soil. Its mechanical properties are not only related to hydrate saturation but also to the occurrence habits of hydrate. The mechanical characteristics of hydrate hosting structures with different habits are different. Considering the failure of structure in gas-hydrate soil under loading, the stress and strain model of hydrate bearing soil is established based on the disturbed state concept to describe the whole process of loading failure of cemented structures. At the same time, the disturbed function expressed by the effective saturation of hydrates is used to describe the development of the internal structure of the hydrated soil under the loading condition. According to the mechanical behavior of hydrate bearing soil, two reference states are described by the ideal elastoplastic model and the Mohr-Coulomb model. The form of this model is relatively simple, and the parameters are easy to be determined. Finally, the three triaxial compression tests are used to verify the model. The results show that the model can reasonably simulate the deformation characteristics of hydrate bearing soil in the process of disturbance.

Key words: gas-hydrate-bearing soil, cemented structures, disturbed state concept, effective saturation