Dynamic characteristics of compacted volcanic Ash under long-term Cyclic loads

This study delves into the dynamic characteristics of compacted volcanic ash under long-term cyclic loads, focusing on the impact of water content, confining pressure, and dynamic stress. The research reveals how these factors influence the deformation and strength of volcanic ash, crucial for the design and safety of infrastructure in volcanic regions. The study employs dynamic triaxial testing to investigate the dynamic properties of volcanic ash, including deformation patterns, dynamic strength, and the evolution of dynamic parameters such as dynamic elastic modulus and damping ratio. The findings highlight the importance of understanding the long-term dynamic engineering geological properties of volcanic ash to ensure the stability and durability of road bases, subbases, and subgrades in volcanic regions. The study also introduces the application of shakedown theory to characterize the accumulated plastic strain, providing valuable insights into the behavior of volcanic ash under cyclic loading. The research concludes that the accumulated plastic strain of compacted volcanic ash is positively correlated with water content and dynamic stress, while increasing confining pressure enhances deformation resistance. The study also reveals that at high dynamic stresses, specimens exhibit shear instability, and under saturated conditions, liquefaction damage occurs as dynamic stresses increase. The dynamic elastic modulus undergoes three stages of reduction, increase, and reduction at accumulated plastic strain below a critical threshold, attributed to structural damage, compression density, and particle breakage during vibration. The damping ratio decreases with cycles of vibrations under unsaturated conditions, while under saturated conditions, it initially decreases and then increases as cycles reach a failure point. This comprehensive analysis provides valuable insights into the dynamic properties of volcanic ash, crucial for the design and maintenance of infrastructure in volcanic regions.