Effect of particle shape on the mechanical behavior of methane hydrate-bearing sediments: A DEM study

Methane hydrate-bearing sediments (HBS) have emerged as a promising energy source, and an in-depth understanding of their mechanical properties is critical for safe exploration and utilization. Previous studies have demonstrated the significant effect of microstructures, such as hydrate distribution patterns and sediment particle-hydrate interactions, on the mechanical behavior of HBS. However, as one of the most important factors determining both particle–particle and particle-hydrate interaction behaviors, particle shape has been insufficiently explored in previous studies. This study employs the Discrete Element Method (DEM) to simulate HBS with various particle angularity, focusing on the effect of particle shape on mechanical behavior of HBS with different hydrate distribution patterns (often referred to as pore habits). By simulating a set of triaxial tests, we found that the particle angularity (defined by sphericity, roundness, and convexity) exerts a significant influence on the strength and stiffness of HBS. Moreover, an anti-rotation effect imposed by particle angularity at the initial loading stage is observed, and the evolution of deviatoric fabric and contact distribution is also influenced by particle shape. This comprehensive analysis underscores the importance of particle shape in modeling HBS and unravels the complex particle–particle and particle-hydrate interaction mechanisms in HBS, offering valuable insights for reservoir exploitation.