(1. 北京科技大學(xué) 金屬礦山高效開采與安全教育部重點實驗室，北京 100083；
2. 北京科技大學(xué) 土木與資源工程學(xué)院，北京 100083；
3. 北京聯(lián)合大學(xué) 北京市信息服務(wù)工程重點實驗室，北京 100101；
4. 中國電建集團(tuán)北京勘測設(shè)計研究院有限公司，北京 100020；
5. 山東科技大學(xué) 礦業(yè)與安全工程學(xué)院，青島 266590)
摘 要: 為探究在不同酸堿性流體環(huán)境作用下孔隙比、浸泡時間對尾礦砂滲透性的影響規(guī)律，選取7組不同孔隙比試樣，設(shè)計變水頭滲透室內(nèi)試驗；通過控制變量法，研究8種浸泡時間下尾礦砂滲透性變化規(guī)律，并利用掃描電鏡和X射線能譜儀分析不同化學(xué)條件下孔隙比對尾礦砂滲透性影響機理。結(jié)果表明：在化學(xué)條件下尾礦砂的孔隙比與滲透系數(shù)存在“似指數(shù)”變化關(guān)系。當(dāng)控制試樣孔隙比為0.65時，在強酸溶液中(pH=3)，尾砂的滲透系數(shù)隨浸泡時間延長而增加，表現(xiàn)為二次拋物線關(guān)系，浸泡1600 s較浸泡200 s增加了56.92%；在強堿環(huán)境下(pH=11)，尾砂的滲透系數(shù)隨浸泡時間呈Logistic函數(shù)下降，浸泡1600 s較浸泡200 s下降了73.66%。基于太沙基、柯森、劉杰等滲透理論擬合得到酸性、堿性、中性三種條件下的修正關(guān)系模型。根據(jù)試驗結(jié)果分析和掃描電鏡觀察發(fā)現(xiàn)，酸性條件下小顆粒尾砂被侵蝕，大顆粒尾砂棱角凸顯，結(jié)合水膜變薄，孔隙增大，滲透系數(shù)變大；堿性條件下，尾砂顆粒表面與尾砂顆粒間有沉淀膠體覆蓋或填充，結(jié)合水膜變厚，孔隙減小，滲透系數(shù)隨之減小。
關(guān)鍵字: 尾礦砂；化學(xué)環(huán)境；滲透系數(shù)；孔隙比；微觀結(jié)構(gòu)
（1. Key Laboratory of High-Efficient Mining and Safe of Metal, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Beijing Key Laboratory of Information Service Engineering, Beijing Union University, Beijing 100101, China;
4. Power China Beijing Engineering Corporation Limited, Beijing 100020, China;
5. School of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao 266590, China）
Abstract:In order to explore the feature rule of pore ratio and soaking time on the permeability of tailings sand under the action of different acid and alkaline fluid environments, seven groups of samples with different pore ratio were prepared. A laboratory experiment of variable head permeability was designed to analyze the permeability of tailings sand. The permeability variation of tailings under eight soaking times was studied by the method of controlling variables. The scanning electron microscope and X-ray energy spectrometer was used to investigate the mechanism between pore ratio and permeability of tailings under different chemical conditions. The results show that a similarity index relationship between pore ratio and permeability coefficient of tailings under different chemical conditions. When the void ratio of the sample is 0.65, in strong acid solution (pH=3), the permeability coefficient of tailings increases with the increase of soaking time, showing a quadratic parabolic relationship. The permeability coefficient of the tailings soaked for 1600 s increases by 56.92% compared with that soaked for 200 s. In the strong alkali environment (pH=11), the permeability coefficient of tailings decreases with the soaking time as a logistic function, and the permeability of tailings decreases by 73.66% in 1600 s compared with that in 200 s. Based on the penetration theory of TERZAGHI, KOSEN and LIU JIE, the modified relationship model is obtained under acidic, alkaline and neutral conditions. According to the analysis of test results and the images observed from scanning electron microscopy, it is found that under acidic conditions the small tailings are eroded and large tailings have prominent edges and corners. Meanwhile, the bound water film thinner, the pore size increases, and the permeability coefficient increases. However, under alkaline conditions, the surface of tailings particles and tailings particles are covered or filled with precipitated colloids. Furthermore, the bound water film becomes thicker, the porosity decreases, and the permeability coefficient decreases accordingly.
Key words: tailings sand; chemical environment; permeability coefficient; pore ratio; microstructure
