Experimental Study of Dynamic Characteristics of Tailings With Different Reconsolidation Degrees After Liquefaction

Abstract

The construction period of most tailing ponds generally lasts for more than 10 years or even decades. During this period, it may be affected by more than one earthquake and is often subjected to vibrations generated by mining activities. The tailings liquefied by earthquakes or vibrations may experience dynamic loads again. Due to the low permeability of tailings, the reconsolidation process of tailings after liquefaction is prolonged. Therefore, changes in the nature of the tailings caused by previous earthquakes will affect the performance of the tailing dam in the subsequent earthquakes. Dynamic triaxial tests and bending element tests were conducted on two kinds of tailings from a copper mine in Southwest China to study this process. The tailing specimens will undergo two consolidation processes and subsequent cyclic loads during the test. The influence of reconsolidation degree, confining pressure, and particle size on the dynamic characteristics and wave velocity of the tailings after liquefaction under cyclic loading was measured. The results show that the reconsolidation degree significantly affects the trend of the excess pore water pressure ratio changing with the increase in the cycle number of loads. The reconsolidation process after liquefaction of tailings will improve its liquefaction resistance. The relationship between the ratio of the cycle number of liquefaction after reconsolidation to the cycle number of first liquefaction and the reconsolidation degree is proposed. In the entire experimental process, the shear wave velocity of the tailings gradually decreases when applying the cyclic load and gradually increases during the consolidation process, including the first consolidation before cyclic loading and reconsolidation after liquefaction. The research results are of great significance to the safe disposal of tailings, especially those in earthquake-prone areas.

Effects of Freeze–Thaw Cycles on Strength and Wave Velocity of Lime-Stabilized Basalt Fiber-Reinforced Loess

“…To ensure the test conditions’ consistency, the same excitation signal was used in all the bender element tests. The calculation formula of V p is shown below [ 46 , 47 , 48 , 49 ]: V p = L 0 /Δ t where L 0 is the effective propagation distance, that is, the height of the specimen minus twice the height of the thin piezo-ceramic plate in the bender element, and Δ t is the propagation time of the P-wave, which is the time difference between the peak of the excitation signal and the peak of the arrival signal.…”

Effect of Wetting and Drying Cycles on the Dynamic Properties of Compacted Loess

“…Te dynamic stress-strain relationship of the saturated compacted loess conforms to the hyperbolic model, whereas the relationship among the initial dynamic shear modulus (G 0 ), the maximum dynamic stress, and the axial consolidation stress conforms to a power function [13,14]. Te dynamic elastic modulus (E d ) of compacted loess decreases with the dynamic strain increasing and tends to stabilize gradually.…”

Comprehensive analysis of the stability of tailings-geotextile composite—Iron Mine Tailings Dam in Gushan, Anhui, China

“…Among them, tailings-geotextile composite heap dry backfilling materials technology can enhance the penetration of consolidation characteristics, and chambers rapidly drain the water body, effectively improve the safety and stability of tailings dam. In recent years, due to the demand for practical engineering, research on tailingsgeotextile composites and their properties has developed rapidly (Wang et al, 2022;Wu et al, 2022).…”