Examination of Damage Evolution in Slurry Masonry Schist Subjected to Biaxial Compressive Stresses

This study used a static bidirectional multifunctional loading system. The system conducted bidirectional compression tests on scaled specimens of slurry masonry schist under freeze–thaw cycling conditions. This study aimed to investigate the influence of bidirectional stress coupling with freeze–thaw cycles on the mechanical properties of slurry masonry schist. The results indicate that lateral pressure can increase the peak stress of slurry masonry schist, while freeze–thaw cycles have an adverse effect on the material’s internal pore structure, counteracting the gain effect of lateral pressure. This study also employed acoustic emission (AE) technology to analyze the evolution of slurry masonry schist failure characteristics. The findings reveal that freeze–thaw cycles accelerate the failure of slurry masonry schist during loading, and lateral pressure to some extent mitigates the damage development of slurry masonry schist. The synergistic effect of lateral pressure and freeze–thaw cycles alters the fracture mode of slurry masonry schist. Acoustic emission signal localization demonstrates numerous AE localization points in the interface transition zone, forming a coherent signal band where cracks propagate toward complete interface penetration. The crack extension process of the slurry masonry schist was investigated using the digital image correlation (DIC) method. The results indicated that macroscopic cracks formed in the strain localization zone, resulting in fracture damage to the specimens, with interfacial debonding identified as the primary failure mode for slurry masonry schist structures.