基于模型试验的镍矿流态化特性与判别

Mechanical Characteristics and Criterion for Nickel Ore’s Fluidization Based on Model Test

随着我国对镍矿需求的不断上升,其运输过程中出现的流态化问题也亟待研究。通过室内可视化小型振动台模型试验,对镍矿流态化细观规律及判别准则进行了研究。首先借助数字图像采集与分析系统,分析了镍矿在流态化过程中的宏观演化现象,对其分层含水率及孔隙水压力的变化规律进行了研究;并根据镍矿流态化机理,借鉴含细粒土液化的判别方法,提出了基于塑性指标的镍矿流态化判别新方法。结果表明:镍矿发生流态化的主要原因是高含水率条件下发生了振动软化,在其振动过程中水分基本不发生迁移,孔隙水压力也基本不发展。通过该判别方法计算得到的含水率结果与模型试验结果基本一致,因此新方法适用于高细粒含量镍矿流态化临界含水率的确定。

With the increasing demand for nickel ore in China,the import volume of nickel ore is increasing day by day.The fluidization of nickel ore in the process of marine transportation needs to be studied urgently.By means of indoor small vibration table modeling tests,the fluidization evolution process and the criterion for nickel ore’s fluidization is studied.Firstly,with the aid of digital image acquisition and analysis system,the macro-evolution of nickel ore in fluidization process is analyzed,and the change rules of water content in layers and pore water pressure are studied.Based on the fluidization mechanism of nickel ore and the discrimination method for liquefaction of fine-grained soil,a new method for fluidization discrimination of nickel ore based on plasticity index is proposed.The results show that the fluidization of nickel ores is mainly caused by vibration softening under high water content conditions,during which water hardly migrates and pore water pressure hardly develops.The moisture content calculated by the discriminant method in this paper is basically consistent with the result of the model test.Therefore,the new method is suitable for determining the critical water content of fluidization of nickel ores with high fine particle content.