A recent study has illuminated the complex mechanical properties of soil-rock mixtures (S-RM) within fault zones, with the potential to significantly impact mining safety and engineering practices. Conducted at the Sanshan Island fault zone located on the Jiaodong Peninsula, this research focuses on the interplay between the proportions of rock blocks and the efficacy of S-RMs, which are pivotal for maintaining structural integrity within mines.
The study utilized triaxial compression tests and numerical simulations to explore how varying rock block proportions (RBP) of 20%, 40%, 60%, and 80% influence both the strength and failure behavior of S-RMs. The researchers observed distinct mechanical responses depending on the RBP level, with considerable correlations between confining pressure and peak strength at lower rock block concentrations.
Specifically, for S-RMs with RBPs of 20%, 40%, and 60%, researchers found "a linear positive correlation between confining pressure and peak strength." This indicates enhanced stability under pressure as the proportion of rock particles increases. Interestingly, when the RBP shifted to 80%, the dynamics changed; the correlation became non-linear, reflecting possible limitations of these mixtures to respond uniformly to increased external loads.
Notably, the findings reveal how cohesion—an important measure of material strength—varies with RBP. The cohesion of the S-RM increased from 83.12 kPa to 119.38 kPa as the proportion of rock blocks swelled, alongside an increase in internal friction angles from 6° to 11°. Such mechanical properties are foundational for predicting the performance of materials used in fault zones, which are traditionally prone to instability due to geological conditions.
Industry stakeholders have much to gain from this research, especially with insights on failure mechanisms. The study categorized behaviors under different RBP levels. With lower RBPs (20% and 40%), samples exhibited shear slip failures characterized by substantial deformation bands. Conversely, higher RBPs resulted primarily in splitting failures at the interfaces of soil and rock particles, attributed to intensified contact forces among densely packed particles.
Understanding these mechanics can directly inform engineering practices, ensuring safer mining operations and preventing geological disasters induced by unstable fault zones. The data and methodologies detailed by this research not only advance the geological science of mining but also serve as invaluable tools for engineers aiming to design more resilient structures.
The research concludes by affirming the social and economic value of these findings, positioning them as a landmark study within mining safety literature. By elucidate the fracture failure laws of rock masses, this work fundamentally contributes to the safe development of human engineering activities, especially as excavation practices continue well past established geological boundaries.