膏体浓密中全尾颗粒运移行为的时空建模与可视化仿真

Ultra-fine tailings thickening and dewatering is an urgent problem in cemented paste backfill. In terms of the interdisciplinary study of mining engineering and information technology, this study proposes a spatio-temporal modeling and visual simulation on the sedimentation and migration behavior of whole-tailings particles during thickening of cemented paste backfill. The technical route includes data acquisition, mesostructure characterization, modeling, law ascertaining, dynamic simulation, and the combination of mechanism interpretation and theory application. From the view point of meso-scale, three-dimension, dynamic, and visualization, the study is conducted in four aspects. (1) A 3D meso-space model for floc will be established, and the internal structure of solid floc and liquid floc water will be quantitatively characterized. (2) The internal effects between the structure evolution and mechanical behaviors of floc and floc water will be ascertained. Then the evolution law of mesoscopic drainage will be obtained during the process of floc water appearing, being sealed, being pressed, deforming, being sheared, being connected, and being discharged. (3) Based on the revealed mesostructure effect of floc, the migration behavior of the whole-tailings will be investigated under the action of two-phases (liquid/solid) coupling during the process of free settling, hindered settling, and compression settling. Thus, the spatio-temporal migration model of whole-tailings particles will be established. (4) Combining with the spatio-temporal dynamics simulation on the particles’ migration behavior of whole-tailings particles under different working conditions, the meso-scale thickening and dewatering mechanism of the whole-tailings particles will be illustrated and the response mechanism between the meso-scale mechanism. The results of this study will lay a solid theoretical foundation for solving the problem of tailings thickening and dewatering, and provide technical approach for promoting the development of cemented paste backfill.

遵循采矿工程与信息技术交叉的研究思路，采用数据获取、细观表征、规律探明、模型构建、动态仿真与机理诠释相结合的技术路线，从细观、三维、动态、可视的角度，针对膏体充填中迫切需要解决的超细尾矿浓密脱水问题，从4个方面展开全尾颗粒沉降运移行为及其时空建模与可视化研究：①建立絮团三维细观结构模型，定量表征固相絮团与液相絮团内含水的细观不规则结构；②探明絮团及絮团内含水细观演化与其力学行为的内在效应，获得絮团内含水自出现-封闭-挤压-变形-剪切-连通-排出过程中的细观排水演化规律；③基于絮团细观结构效应，探究液-固两相耦合作用下全尾颗粒在自由沉降-干涉沉降-压缩沉降全过程的运移行为，构建全尾颗粒时空运移模型；④实现全尾颗粒沉降运移行为的可视化动态仿真，结合不同工况诠释全尾颗粒细观尺度上的浓密脱水机理。本研究为解决全尾矿浓密脱水难题奠定理论基础、为推进膏体充填发展提供技术途经。

本项目针对膏体充填中超细尾矿浓密脱水问题，通过搭建小型动态浓密试验平台，开展了沉降至压密过程中絮团结构、压密区床层孔隙结构、床层料浆浓度变化规律、床层间水反渗排放机制以及颗粒时空运移行为等研究，从细观、三维、动态、可视的角度明晰了全尾矿浓密脱水机理，取得了以下研究成果：.（1）研究内容一：絮团细观结构三维建模与表征。分析了不同絮凝条件对絮团等效直径产生的影响以及沉降过程中絮团等效直径随沉降高度的变化规律；获取了不同实验条件下压密区絮团弦长的分布状态以及平均弦长的变化趋势，揭示了絮团结构的变化机制。.（2）研究内容二：絮团细观排水演化规律研究。分析了耙架剪切前后床层孔隙微细观结构的演变规律，计算了床层压力随床层高度的变化情况，揭示了孔隙结构变化对床层压力的响应机制，获取了料浆的渗透性随床层高度的演变规律，明晰了床层间水在力学作用下反向排出的作用机理。.（3）研究内容三：全尾颗粒时空运移模型构建。分析了沉降区絮团结构的沉降速度变化，获取了絮团沉降速度随沉降高度的变化趋势，得到了絮团沉降速度随絮团等效直径的变化规律；分析了不同实验条件下压密区床层界面沉降速度随时间的变化，揭示了压密区尾砂颗粒接触形态对沉降行为的影响机理。.（4）研究内容四：全尾颗粒沉降行为的可视化动态仿真及机理诠释。从可视化角度给出了不同工况条件下给料井和浓密机模型内絮团运移行为的分布云图，分析了给料井和浓密机内湍流场强度和絮团沉降速度变化，并获取了絮团结构随絮凝条件、时间和沉降高度的分布状态变化规律。