Macroscopic and Mesoscopic Mechanical Properties of Mine Tailings with Different Dry Densities under Different Confining Pressures

Zhi-Jun Zhang,Ling-Ling Wu,Huai-Miao Zheng,Ya-Kun Tian,Yao-Hui Guo,Xi-Xian Wang,Zhengyang Song,Lin Hu

doi:10.1155/2020/8832335

Abstract

Particle flow numerical simulation software (PFC3D) was utilized to establish the consolidated-undrained triaxial compression test numerical models of mine tailings with different dry densities to deeply investigate the macroscopic and microscopic characteristics of mine tailings in a tailing pond in Hunan Province. Comparing the results of the simulation and the laboratory experiment, the mesoscopic parameters of the particle flow numerical simulation were obtained through continuously adjusting the mesoscopic parameter with the higher degree of agreement between the stress-strain curve, the peak strength, and the elastic modulus as the determining standard. The macroscopic and microscopic characteristics of mine tailings were studied from the perspectives of stress-strain, axial strain-volume strain, coordination number, particle velocity vector, and contact force between particles. After numerous numerical tests, it was found that the PFC3D simulation results are consistent with experiment results of the dry density tailing samples under different confining pressures; compared with the high confining pressure, the simulation test results at lower confining pressures were more with that of the laboratory tests; low density and high confining pressure both have inhibitory effect on the dilatancy characteristics of triaxial samples; with the same confining pressure, the dilatancy tendency of low dry density samples is suppressed comparing with the high dry density samples. The initial coordination number of the numerical model is large, which proves that the contact degree of the model is good to some extent.

Highlights

Tailings are complex geotechnical materials whose mechanical properties are greatly affected by various factors
Cui et al [5] embedded the mode search method in the least square method to automatically calibrate the mesoparameters of the discrete element numerical test
Following conclusions are drawn: (1) By comparing the laboratory test with the PFC triaxial compression simulation test, the stress-strain curve, peak strength, and elastic modulus of the numerical simulation of each dry density tailing sample under different confining pressures and the laboratory test are in good agreement

Summary

Introduction

Tailings are complex geotechnical materials whose mechanical properties are greatly affected by various factors. As the main material of the tailing dam, the mechanical properties of the tailings exhibit great relevance with the safe operation of the tailing dam. It is of great practical significance of studying the tailing mechanical properties. In geotechnical and rock materials studies, many scholars at home and abroad have paid great attention on researching it from the perspective of discrete element particle flow [1,2,3,4]. The relationship between mesoparameters and macroparameters in discrete-element particle flow simulation has always been a difficult point. Cui et al [5] embedded the mode search method in the least square method to automatically calibrate the mesoparameters of the discrete element numerical test

Methods

Results

Conclusion