含水率对放矿松动体形态的细观影响

Influence of moisture content on the shape of isolated movement zone in mesoscale

为从细观尺度研究矿岩含水率对自然崩落法放矿松动体形态的影响,对非饱和矿岩颗粒间的受力进行了分析,并分别将放矿场内细颗粒流与大块离散矿岩利用格子波尔兹曼法与离散元法处理,基于格子波尔兹曼法-离散元法耦合算法建立自然崩落法放矿模型,得出含水率与放矿松动体形态间的关系,并通过将模拟结果与已有研究结论进行对比分析,验证了基于格子波尔兹曼法-离散元法耦合算法的放矿模型准确性及可靠性.研究表明：矿岩含水率对放矿松动体形态影响显著,在同等矿岩放出质量分数情况下,随着含水率的增大,放矿松动体高度呈先增大后减小的趋势,放矿松动体形态先逐渐变为细长型再逐渐恢复,放矿松动体形态变化的含水率临界值在10%左右.

Block caving mining has the advantages of large production capacity,safe operation,low mining cost,and easy organization and management. Therefore,it is considered as one of the natural alternatives to the current open cut mining. The migration law of ore-rock and the design of ore drawing parameters during ore drawing are the key to block caving mining. The caving rocks usually contain pore water between the fine particles,therefore,the caving rock in an unsaturated state is a solid-liquid-gas three-phase coupling field. The electric double layer force as well as the ionic hydration force,electrostatic force,and Van der Waals force result in the interaction between adjacent particles on a molecular scale. However,the interaction is also resulted in the force of the liquid bridge. To explore the influence of moisture content on the shape of an isolated movement zone in block caving method under ore drawing in mesoscale,the stress between unsaturated ore particles was analyzed. The fine particles flow and discrete bulks of ore-rocks were investigated using lattice Boltzmann method（ LBM） and discrete element method（ DEM）,respectively. Based on the LBM-DEM coupling algorithm,the ore-drawing models of the block caving method were constructed,and the relationship between the moisture content and the shape of the isolated movement zone was obtained. The accuracy and reliability of the ore-drawing models based on the LBM--DEM coupling algorithm were verified by comparing the simulation results with the existing research results. The results indicate that the moisture content of ore-rock has significant effects on the shape of the isolated movement zone. When the same ore-rock mass fraction is discharged,with an increase of moisture content,the height of isolated movement zone increases and then decreases,and the shape of isolated movement zone becomes slender and then is restored gradually. The critical value of moisture content during the change of isolated movement zone shape is about 10%.