摘要
通过微细观结构分析、低场核磁共振量化研究,科学、准确地描述膏体跨尺度颗粒群存在形态与水分赋存状态,并基于有限元和离散元耦合数值分析方法分析了泵压扰动下膏体颗粒流态演化规律.研究发现,膏体料浆中的吸附水、间隙水和弱自由水存在动态连通与转化行为,并主要以吸附水形式存在,低场核磁共振技术(Low-field nuclear magnetic resonance,LF-NMR)弛豫强度与吸附水峰面积非线性增强,与料浆的流动表现出显著的正相关性.液网结构与絮网结构反映了导水通道的活跃性与力链结构的强度,共同组成了膏体稳定性与流动性的双支撑骨架结构.通过Fluent-EDEM软件耦合模拟,分析了脉冲泵压环境颗粒运动行为,在速度差的影响下高、低流速颗粒冲击扰动加剧,力链接触作用增强,流态均匀性和整体颗粒运动稳定性可有效提高.
The development of green resources and deep mining face several challenges,including prominent safety hazards associated with deep mining and severe environmental pollution in mining areas.Paste-filling technology,designed to eliminate tailing ponds and control subsidence in mined-out regions,innovatively uses mined solid waste with the principle of“one filling for three wastes,one waste treatment for two harms,”thus forming a mining approach characterized by a high recovery rate and low impoverishment rate.This technology possesses unique advantages in both mitigating environmental pollution and managing stress factors in deep mining.Paste filling has emerged as an effective solution for deep and green mining.Paste backfill technology,with its considerable potential,may become an impactful solution for future deep and green mining.However,it is difficult to accurately describe the rheological behavior and flow process of paste due to its diverse composition and variable transport environment.In this study,micro-and macrostructures and quantitative analysis of low-field nuclear magnetic resonance(LF-NMR)were employed to describe the existing form of cross-scale particle groups and the water occurrence state in a paste.In addition,the flow pattern evolution law of paste particles under the disturbance of pump pressure was analyzed using the finite element and discrete element coupling numerical analysis method.The results indicated that adsorption water,interstitial water,and weak free water in paste exhibited dynamic connectivity and transformation behavior,with water predominantly existing in an adsorbed state.According to the analysis of LF-NMR,the relaxation intensity and peak area of the adsorbed water were nonlinearly enhanced,demonstrating a pronounced positive correlation with the flow performance of the paste.The liquid network structure and the floc network structure reflected the activity of the waterflow channel and the strength of the force chain structure,respectively.These components together constituted a double-supported skeleton structure that determined the stability and fluidity of the paste.Furthermore,Fluent-EDEM coupling simulation was conducted to examine the particle movement behavior in a pulse-pumping environment;the velocity difference amplified the force chain contact effect,intensifying the impact disturbance of particles with high and low flow velocities,and considerably enhanced the flow uniformity and overall stability of particle motion.Generally,this study examined the mechanical response mechanism between particle groups and fluid drag in paste,establishing the intrinsic relationship between particle physical properties,spatial structure,and rheological characteristics.Furthermore,a constraint mechanism and control scheme were proposed for the long-distance and high-drop steady-state transportation of paste in a pulse compression environment.The results of this study provide valuable insight into the theoretical and engineering implications for achieving safe,environmentally friendly,economical,and efficient paste filling.
作者
夏志远
程海勇
吴顺川
姜关照
刘津
孙伟
刘泽民
XIA Zhiyuan;CHENG Haiyong;WU Shunchuan;JIANG Guanzhao;LIU Jin;SUN Wei;LIU Zemin(Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《工程科学学报》
EI
CSCD
北大核心
2024年第1期11-22,共12页
Chinese Journal of Engineering
基金
国家自然科学基金资助项目(52074137)
云南省重大科技项目(202202AG050014)
云南省面上基金(202201AT070151)
云南省创新团队资助项目(202105AE160023)。
关键词
膏体充填
脉冲泵压
低频核磁
水分迁移
双骨架结构
流变行为
paste backfill
pulse pump pressure
LF-NMR
moisture migration
double skeleton structure
rheological behavior
