Abstract: The main hydrate storage layer in the South China Sea is fine sand reservoir. To obtain the mechanical properties of the hydrate reservoirs rapidly and accurately is critical to the development and utilization of the nature gas hydrate. A modified Mohr-Coulomb model was introduced to describe the stiffness, strength and deformation characteristics of hydrate sand by using the commercial finite element software ABAQUS. The constitutive mode response was calibrated by the isotropic compression tests in conventional sand samples and the plastic parameters were determined by the drained triaxial test on the hydrate bearing sand samples. A large deformation finite element method in the form of Arbitrary Lagrange-Eulerian was used to simulate the cone penetration tests in the hydrate sand layers. The numerical model allowed the different flow velocity between the soil and the mesh to avoid the element distortion around the cone tip. An empirical equation for the cone tip resistance varied with different saturation was obtained.

Key words: nature gas hydrate, finite element method, large deformation analysis, cone penetration test