Dynamic Characteristics and Strength of Tailings Sand: A New Perspective
In a groundbreaking study, researchers have delved into the dynamic characteristics of tailings sand under various stress conditions. The research provides a detailed analysis of the relationship between dynamic shear stress and failure vibration number, liquefaction stress ratio, dynamic strength, and dynamic pore pressure.
Unveiling the Dynamic Shear Stress
Dynamic tests were carried out on tailings with consolidation stress ratios (Kc) of 1.0, 1.5, and 2.0. These represent confining pressures of 100, 150, and 200 kPa. The results revealed a linear relationship between dynamic shear stress and failure vibration times, showcasing a high correlation coefficient.
The Liquefaction Stress Ratio
The study also looked into the liquefaction stress ratio, which is the ratio of confining pressure to axial dynamic stress amplitude. The findings indicated that the confining pressure has minimal impact on this ratio. This derives from the large surface area and poor roundness of tailings sand particles, forming a tightly consolidated structure that evenly distributes stress.
Dynamic Internal Friction Angle and Cohesion
Interestingly, the dynamic internal friction angle was found to decrease with an increase in failure vibration time. It also increased with consolidation ratio and dry density. Dynamic cohesion, on the other hand, remained unaffected by these three factors and stuck at zero, a clear indication that tailings sand is a non-cohesive granular material.
Fitting the Facts into a Model
A polynomial fitting approach was applied to establish the relationship between liquefaction stress ratio and consolidation ratio, achieving a correlation coefficient above 99%. The dynamic pore pressure ratio was also scrutinized, revealing a gradual increase with vibration ratio and a noticeable influence by the consolidation ratio. The study proposed a new dynamic pore pressure growth exponential function model. This model is suitable for both isobaric and anisotropic consolidation and showed high agreement with the test data.
Finally, the study calculated the maximum dynamic elastic modulus and maximum dynamic shear modulus of tailings sand under different conditions. These findings offer a solid foundation for dynamic response analysis of tailings sand, contributing significantly to our understanding of its stability during earthquakes and other seismic events.
