Constitutive model for gas hydrate-bearing soils considering different types of hydrate morphology and prediction of strength-band

A hypoplastic model for hydrate‐bearing sand considering hydrate saturation and grain breakage

“…9,12 With the increased hydrate saturation, MH-bearing T 𝑏 sand varies from strain hardening to softening, indicating that hydrate formation benefits strength. Compared with the peak strength, the increment in critical stress is less than that of peak stress which is described by the reduction of hydrate saturation effect by Equation (40). Under constant confining pressure, the contraction converts to dilation due to the increase of hydrate saturation, especially for (𝑆 ℎ = 73.8%), which exhibits evident dilatancy.…”

“…To better understand the mechanical response of hydrate-bearing sands at high confining pressure, some theoretical analysis 34,35 has been developed to satisfy the requirement of rapid development of methane gas hydrate exploitation. Some constitutive models, including elastoplasticity [36][37][38][39] and hypoplasticity, 5,16,17 have been developed to study the effect of hydrate saturation on mechanical responses of different soil, such as MH-bearing sand, 35,[40][41][42][43] MH-bearing silt 34 and CO 2 hydrate-bearing sand. 13,44 These models are capable of predicting mechanical behavior and deformation characteristics of hydrate-bearing sands in the complex environments with different hydrate saturation and confining pressures.…”

“…Although the hydrate saturation effect was successfully incorporated into some constitutive models, 35,[40][41][42][43] the unified constitutive model for the coupling effect of hydrate and grain breakage has been not reported. With the framework of classical elastoplasticity, the bottleneck of complicated calibration procedures might be an obstacle to investigate the coupling effect of hydrate and grain breakage.…”

Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear

“…The failure line based on the Mohr-Coulomb failure criterion in q − p plane is defined as Equation (10) [37]: The slope of the total stress path is 3. O 1 and O 2 represent beginning points of stress paths with low and high initial effective confining pressure, respectively.…”

“…A series of geotechnical tests have been carried out, and the results show that geomechanical properties (i.e., shear strength, stiffness and dilatancy) of hydrate-bearing sediments are largely controlled by the hydrate saturation and hydrate pore habits, such as pore-filling, load-bearing, and cementation [7,8]. Based on these basic understandings, different geomechanical constitutive models have been developed to predict the mechanical response of hydrate-bearing sediments during numerical simulations of hydrate production [9,10].…”