干湿循环和含水率对尾砂压缩固结特性的影响研究

为辅助计算尾矿存积的沉降距离,指导放矿、尾矿子坝堆筑,提高尾矿坝的经济效益.研究干湿循环作用和含水率对湖南某金属尾矿库尾砂的压缩固结特性的影响.对含水率为10％、12％、14％、16％和18％的尾砂分别进行0～5次脱湿—吸湿—再脱湿试验,借助GZQ-1型全自动高压固结仪对试样开展了快速固结试验.研究结果表明:(1)相同...

Study on Consolidation Characteristics of Tailings with Different Moisture Content Under Dry-Wet Cycle

With the improvement of mineral processing technology，the amount of tailings in storage is increasing year by year，and the particle size of tailings is getting finer and finer.However，such tailings have poor permeability，good water holding performance，long consolidation time and low mechanical strength.Such tailings often have problems such as difficult drainage，slow deposition and poor stability in the process of dam-filling.In the complex climate and geographical environment，rainfall infiltration，water evaporation，repeated rise and fall of saturation line （that is，under the condition of dry-wet cycle），earthquake and so on will be encountered.These factors can not be ignored for the settlement of fine tailings pond.In order to help calculate the settlement distance of tailings deposit and guide ore drawing and tailings dam construction，the influence of dry-wet cycle and moisture content on the compression consolidation characteristics of tailings of a metal tailings pond in Hunan Province was studied.The tailings with water content of 10%，12%，14%，16% and 18% were subjected to 0~5 times of dehumidification-moisture absorption-dehumidification tests respectively，and rapid consolidation tests were carried out on the samples with the help of GZQ-1 automatic high-pressure consolidation instrument.The results show that：（1）Under the same conditions，the void ratio decreases with the increase of pressure.Without the dry-wet cycle，the void ratio of the sample at the optimum moisture content is the smallest，and the void ratio of natural moisture content，optimum moisture content and saturated moisture content changes in a U-shaped curve in turn.After the dry-wet cycle，the volume of tailings sample expands slightly，and the internal water-gas channel changes.After graded loading，the internal particles fill the pores，and finally the structure tends to be stable.（2）Under the same number of cycles，the compression coefficient increases with the increase of water content， Under the same moisture content，the compression coefficient changes in a “Λ” shape with the increase of the number of dry-wet cycles.The number of dry-wet cycles and moisture content can increase the compactness of tailings and reduce the compression coefficient by changing the bonding effect and capillary water pressure of tailings cement.（3）Without drying-wetting cycle，the con-solidation coefficient first rises and then decreases with the increase of water content. At the same moisture content，the change of consolidation coefficient is approximately M-shaped with the increase of the number of dry-wet cycles.The stress in the early cycle process is mainly dominated by capillary water pressure.When the particles move stably and the pore structure of tailings is fully developed，the stress is dominated by cohesive force and friction force.Through the above three points，we can understand the stress characteristics of tailings sand consolidation process，assist in calculating the settlement distance of tailings accumulation，and guide ore drawing and sub-dam construction.Monitoring the environmental temperature and precipitation，controlling the water content of tailings and the accumulation period of tailings can improve the economic benefit and stability of tailings dam.