【摘要】：使用尾礦筑壩是礦山生產(chǎn)中資源再利用的一種有效方式。尾礦固結(jié)沉積效果直接關(guān)系到尾礦庫(kù)的建設(shè),包括了對(duì)干灘形成條件、子壩修筑以及壩體穩(wěn)定性的影響。因此,研究如何加速尾礦固結(jié)沉積速度,提高干灘強(qiáng)度,對(duì)尾礦庫(kù)工程意義重大。本文以南京梅山高濃度尾礦筑壩工程為例,采用現(xiàn)場(chǎng)試驗(yàn)、室內(nèi)土工試驗(yàn)、數(shù)值計(jì)算和工程實(shí)際結(jié)合的方法,對(duì)高濃度尾礦壓濾筑壩以及加速尾礦沉積固結(jié)措施作了初步研究。本文所做的主要工作和取得的研究成果如下所列：(1)通過(guò)試驗(yàn)對(duì)高濃度尾礦筑壩的可行性進(jìn)行了研究,得出此尾礦壓濾之后可以用于干堆筑壩的結(jié)論。在高濃度放礦條件下,對(duì)干灘50m處尾礦的固結(jié)進(jìn)行了相關(guān)計(jì)算,結(jié)果顯示此放礦模式下尾礦沉積固結(jié)不完全,修筑三級(jí)子壩靜力穩(wěn)定性不滿足工程要求。(2)在高濃度放礦尾礦固結(jié)不完全的情況下,考慮到土袋特有的工程特性,通過(guò)拋土袋擠淤的方法加固干灘,并經(jīng)過(guò)計(jì)算得出了擠淤斷面的形狀和擠入的深度。在此基礎(chǔ)之上,對(duì)壩體的靜力穩(wěn)定性進(jìn)行了校核,結(jié)果表明滿足穩(wěn)定性要求,驗(yàn)證了擠淤加固干灘的可行性。(3)現(xiàn)場(chǎng)做了尾礦高濃度排放流槽試驗(yàn)和庫(kù)區(qū)尾礦稀釋排放試驗(yàn)。試驗(yàn)過(guò)程中保證尾礦流量一致,一段時(shí)間后,對(duì)流槽和庫(kù)區(qū)相同位置的尾礦進(jìn)行了采樣分析。通過(guò)對(duì)顆粒組成進(jìn)行分析,發(fā)現(xiàn)尾礦稀釋之后低濃度排放的顆粒分選效果比高濃度直接排放好,50m干灘內(nèi)粗顆粒(粒徑大于0.075mm)的含量更高。運(yùn)用Geo-studio軟件對(duì)高濃度放礦和低濃度排放50m處尾礦的固結(jié)和壩體的穩(wěn)定性進(jìn)行了對(duì)比計(jì)算,結(jié)果表明：低濃度排放庫(kù)區(qū)的浸潤(rùn)線埋深更深,尾礦固結(jié)基本完成,壩體相對(duì)安全。為尾礦庫(kù)高濃度輸送低濃度排放工藝的研究提供了有力的依據(jù)。(4)高濃度尾礦稀釋排放之后,庫(kù)區(qū)尾礦砂分布區(qū)域增大,飽和松砂在受到地震或其他振動(dòng)時(shí)易發(fā)生液化。通過(guò)振動(dòng)進(jìn)行預(yù)液化處理,液化之后土顆粒重組,變得密實(shí),為后期進(jìn)一步加固和筑壩做準(zhǔn)備。利用土工動(dòng)三軸試驗(yàn),選取不同的振動(dòng)幅值、振動(dòng)頻率、固結(jié)比,對(duì)尾礦砂的液化特性進(jìn)行了研究。結(jié)果表明：振動(dòng)幅值越大,土體液化所需的時(shí)間越短；隨著振動(dòng)頻率的升高,孔壓的上升速率增大,土體抗液化強(qiáng)度降低,越容易發(fā)生液化；增大固結(jié)比,土體抗液化強(qiáng)度提高。這為現(xiàn)場(chǎng)預(yù)液化和夯實(shí)試驗(yàn)研究提供了借鑒。
[Abstract]:Using tailings to build dams is an effective way to reuse resources in mine production. The effect of tailings consolidation and deposition is directly related to the construction of tailings reservoir, including the influence on the formation condition of dry beach, the construction of sub-dam and the stability of dam body. Therefore, it is of great significance to study how to accelerate the tailing consolidation and deposition speed and improve the dry beach strength. Taking the high concentration tailings dam construction project of Meishan in Nanjing as an example, using the methods of field test, laboratory geotechnical test, numerical calculation and engineering practice, this paper makes a preliminary study on the high concentration tailings pressure filter dam construction and the measures to accelerate the consolidation of tailings deposition. The main work and research results obtained in this paper are listed as follows: (1) the feasibility of high concentration tailings dam construction is studied through experiments, and the conclusion that the tailings can be used for dam construction in dry pile after pressure filtration is obtained. Under the condition of high concentration drawing, the consolidation of tailings at 50 m in Gantan is calculated. The results show that the consolidation of tailings is not complete under this drawing model. The static stability of the third grade sub-dam is not satisfied with the engineering requirements. (2) under the condition of incomplete consolidation of high concentration tailings, considering the special engineering characteristics of soil bag, the dry beach is strengthened by throwing soil bag and squeezing and silting. The shape and depth of extrusion section are calculated. On this basis, the static stability of the dam body is checked, and the results show that the stability requirement is satisfied, and the feasibility of strengthening dry beach by squeezing silt is verified. (3) High concentration discharge trough test of tailings and dilution discharge test of tailings in the reservoir area are done in the field. In the process of experiment, the tailings flow rate is consistent. After a period of time, the tailings in the same position of flow trough and reservoir area are sampled and analyzed. Through the analysis of particle composition, it is found that the concentration of coarse particles (diameter larger than 0.075mm) in 50 m dry beach is higher than that in high concentration direct discharge of coarse particles (larger than 0.075mm) after dilution of tailings. By using Geo-studio software, the consolidation of tailings and the stability of dam body at high concentration drawing and 50 m low concentration discharge are compared and calculated. The results show that the infiltration line of low concentration discharge reservoir area is deeper, the tailings consolidation is basically completed, and the dam body is relatively safe. It provides a powerful basis for the study of high concentration and low concentration tailings discharge technology. (4) after dilution and discharge of high concentration tailings, the distribution area of tailings increases, and saturated loose sand is easily liquefied when it is subjected to earthquake or other vibration. Through vibration pre-liquefaction treatment, soil particles are reorganized and become dense after liquefaction, which makes preparation for further reinforcement and dam construction in the later stage. The liquefaction characteristics of tailings have been studied by using geo-dynamic triaxial tests with different vibration amplitudes, vibration frequencies and consolidation ratios. The results show that the larger the amplitude of vibration, the shorter the time required for soil liquefaction, with the increase of vibration frequency, the increase rate of pore pressure, the decrease of soil anti-liquefaction strength, and the increase of consolidation ratio. The liquefaction strength of soil is improved. This provides a reference for field pre-liquefaction and tamping test research.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TD926.4

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本文編號(hào)：2134641