Investigation on dynamic splitting mechanical properties of weakly cemented siltstone based on digital image correlation method and FracPaQ algorithm

Soft strata composed of weakly cemented rock are frequently subjected to dynamic loads in underground energy mining engineering, yet the dynamic mechanical properties of these materials remain insufficiently explored. In this study, dynamic splitting tests were conducted on Brazilian disc specimens of weakly cemented siltstone to assess their dynamic mechanical and failure characteristics. The findings revealed that both dynamic strength and dissipated energy increased under higher stress rates. A dynamic splitting strength model for weakly cemented siltstone was subsequently developed based on the incubation time criterion. Additionally, the digital image correlation technology was employed to analyze strain variations during the initiation of the main crack, and the quantitative analysis of the fragmentation process indicated that average opening rates increased with rising stress rates. The FracPaQ algorithm was also applied to further characterize fracture patterns under varying stress rates, demonstrating that the Gaussian function accurately represented the relationship between deflection angles and fracture trace lengths. These research outcomes can provide essential mechanical parameters and a theoretical foundation for the safety assessment of weakly cemented rock strata in coal mining.