Mechanical characterization of hydrate-bearing clayey-silty sediments with layered sediment distribution: Effects of hydrate saturation and effective confining pressure

The layered distribution of sediments significantly influences the mechanical properties of hydrate-bearing sediments (HBS). Understanding these mechanical properties is essential for the safe and efficient extraction of hydrates. In this study, a series of consolidation and drainage tests were conducted on hydrate-bearing clayeysilty sediments (HBCSS) with a layered sediment distribution. The effects of hydrate saturation (Sh) and effective confining pressure (sigma ') on the mechanical properties of layered hydrate-bearing clayey-silty sediments (LHBCSS) were investigated. A comparative analysis was conducted on the mechanical properties of LHBCSS versus those in uniform HBCSS. The impact of various layering sequences of sediments on the mechanical parameters of HBCSS is discussed. The results of the study indicate that the stress-strain (q-epsilon a) curves of the LHBCSS are primarily characterized by strain hardening. At lower Sh, the hydrate significantly influences the stiffness of the layered specimen while having a lesser impact on its failure strength (FS). The contribution of different sediment layers to the strength of HBCSS is influenced by the sigma'. Different layering sequences in sediments significantly influence the mechanical properties of HBCSS. In particular, the mechanical properties of the upper sediments govern the mechanical properties of the LHBCSS.