中国西部矿区厚松散层的溃沙临界流速与水沙流动特征

以陕北榆横矿区为例，研制全程可视化水沙两相高速流动试验装置，开展颗粒起动试验、溃沙试验和水沙两相流动试验.试验结果表明:细颗粒的流失是溃沙的先决条件，为粗颗粒的运移创造膨胀空间.0.3~0.6mm风积沙颗粒之间主要以碰撞的形式传递能量，而0.15~0.3mm的风积沙颗粒之间的相互摩擦和挤压作用占优，相比于碰撞作用能量损失较少，相同时间内出沙量随着颗粒粒径的增大呈递减趋势.随着轴向应力的不断增大，风积沙所需要的溃沙临界流速也越来越大.当风积沙粒径d<0.6mm时，溃沙时渗流状态为线性层流，临界流速为0.03~0.4cm/s.单位时间内溃沙量与水力梯度成正比，表明含水层水压力是决定溃沙灾害程度的关键因素.

Critical Velocity of Sand Inrush and Flow Characteristics of Water-Sand in Thick Unconsolidated Formations of Mine in Western China

Taking the Yuheng mine in Northern Shaanxi as an example， aeolian-sand incipience experiment and water-sand inrush experiment were expansion by high-velocity seepage and entire visual equipment of water-sand two-phase flow. The experiment results indicated that， the loss of fine particles is the precondition of water-sand inrush and creates expansive space for the coarse particle migration. The process of water-sand inrush is a physical process， when the aeolian-sand size between 0.3~0.6mm， the energy transmits mainly in the form of particles collision.But it is different for the aeolian-sand size between 0.15~0.3mm， because the friction and squeeze are in the dominant role， that will lose less energy compared with collision. So the variation mass of aeolian-sand inrush is inversely proportional to the particle size. The critical velocity of aeolian-sand inrush is becoming higher with the increasing of axial stress. When the aeolian-sand begins to move， the seepage state is linear laminar flow and the critical velocity is 0.03~0.4cm/s for the aeolian-sand size d<0.6mm.The mass of sand inrush is proportional to the hydraulic gradient in unit time. It can be deduced from this result that water pressure of aquifer is the key factor， which greatly decisive the disaster degree of water-sand inrush.