Microscopic Structural Evolution of Deep-Sea Sediments During Shear Processes

Abstract The microscopic structural characteristics of deep-sea sediments play a significant role in determining their macroscopic mechanical behavior. Particularly under shear processes, the evolution of microscopic structures is crucial for understanding the mechanical response and engineering applicability of deep-sea sediments. This study developed a nondestructive shear plane extraction technique and systematically quantified particle/pore alignment evolution under varying shear strain rates through SEM-Image recognition integration. Results demonstrate strain-rate dependent restructuring mechanisms: Low-rate shear induces localized faulting with heterogeneous pore distribution, while high-rate shear enhances directional alignment of particles and pores along the shear orientation. Quantitative descriptors including macro porosity reduction of 17.4%∼33.5%, micro porosity increase of 14.4%∼23.8%, fractal dimension reduction, and probability entropy reduction reveal microstructure reorganization patterns. The observed microstructure evolution under varying shear rates provides crucial insights into the deformation behavior of deep-sea sediments.