A modified damage constitutive model of gas hydrate-bearing sediments based on discrete element method

Based on a series of discrete element method (DEM) simulations, a modified damage constitutive model that can predict the mechanical behavior of gas hydrate-bearing sediments (GHBS) has been developed. A new method for preparing the GHBS sample with different gas hydrate saturations is proposed. According to the triaxial compression simulation tests, the stress–strain curves, Mohr’s circles, and their envelopes of GHBS samples were obtained. Based on the results of simulation tests, material parameter equations for GHBS were established. Using the Drucker–Prager failure criterion, a modified damage constitutive model was constructed that can predict the mechanical behavior of the GHBS under high confining pressure more accurately than a typical damage constitutive model. The effects of confining pressure and gas hydrate saturation on the mechanical behavior of GHBS were investigated using the modified damage constitutive model. The model’s correctness is demonstrated by a comparison with simulation test results. This article can be used as a reference by researchers working on gas hydrate drilling design and analysis.