本文選題：尾礦壩 + 粒徑分布規(guī)律��； 參考：《昆明理工大學》2015年碩士論文

【摘要】：尾礦庫是維持礦山正常生產(chǎn)的重要構筑物,其穩(wěn)定性直接關系到其周邊的安全性,因此,對其穩(wěn)定性進行研究是非常有必要的。目前,分析尾礦庫壩體穩(wěn)定性的方法主要有極限平衡法、有限元法和有限差分法。極限平衡法分析壩體穩(wěn)定性時將巖土體作為剛體來研究,且需提前假設滑動面,與實際情況不符。有限元法和有限差分法雖然克服了以上兩個問題,但其將尾砂作為連續(xù)的彈塑性體來研究,也與實際存在一定的差異。并且,這幾種方法都不能直觀地觀察尾礦壩的失穩(wěn)過程。本文以某尾礦庫為工程背景,將尾砂模擬為散體材料,在考慮庫內尾砂分布規(guī)律的前提下,采用顆粒流離散元軟件PFC2D對該尾礦庫不同工況下的穩(wěn)定性及失穩(wěn)過程進行了研究。本文完成了以下幾個方面的內容：(1)在距尾礦壩放礦口不同距離進行尾砂取樣,然后在通過篩分試驗分析了各組尾砂樣品的平均粒徑,最后,將平均粒徑與距離之間的關系進行擬合,分析尾礦庫內尾砂的沉積規(guī)律。(2)針對PFC2D中無黏結材料、接觸黏結材料及平行黏結材料,利用正交試驗設計方法分別設計了9組微觀參數(shù),然后利用PFC2D軟件對每組試樣進行了雙軸模擬試驗,通過模擬試驗得出的偏應力-應變曲線、體積應變-軸向應變曲線及摩爾-庫倫曲線計算出其對應的宏觀參數(shù),最后通過對宏觀參數(shù)進行極差分析得出了不同材料微觀參數(shù)對宏觀參數(shù)影響程度的排序。(3)以微觀參數(shù)對宏觀參數(shù)的影響規(guī)律為基礎,對尾礦壩模型中的基巖、初期壩及尾砂微觀參數(shù)進行了標定,使模型中材料的宏觀力學特性與實際一致。(4)根據(jù)尾礦庫內尾砂沉積規(guī)律建立了尾礦壩PFC2D模型,然后,以強度折減法的基本思想為基礎,編寫了強度折減函數(shù)得出了采用PFC2D軟件模擬時正常水位、洪水位和地震洪水位時尾礦庫的安全系數(shù),并與極限平衡法的結果進行了對比分析。采用PFC2D軟件得出的安全系數(shù)是偏大的,這主要是由于PFC2D軟件所采用的微觀參數(shù)會同時對多個宏觀參數(shù)產(chǎn)生影響,且微觀參數(shù)與宏觀參數(shù)之間并不是線性關系。(5)在尾礦壩模型中設立了監(jiān)測圓,對強度折減條件下監(jiān)測圓內部的應力變化情況進行了監(jiān)測,通過觀察應力變化曲線及模型中顆粒的位移情況,分析了不同工況下尾礦壩失穩(wěn)破壞的形態(tài)及其發(fā)展過程。尾礦壩在三種工況下的破壞滑動面都為圓弧形,特殊運行條件下的圓弧滑面最深,洪水位運行條件下的圓弧滑面次之,正常水位運行條件下的圓弧面最淺,與極限平衡法得出的結果一致。
[Abstract]:Tailing reservoir is an important structure to maintain the normal production of mines, and its stability is directly related to its peripheral security. Therefore, it is very necessary to study its stability. At present, the main methods to analyze the stability of tailing dam are limit equilibrium method, finite element method and finite difference method. When the limit equilibrium method is used to analyze the stability of the dam, the rock and soil are considered as rigid bodies, and the sliding surface should be assumed in advance, which is not in accordance with the actual situation. Although the finite element method and the finite difference method overcome the above two problems, the tailings are studied as a continuous elastoplastic body, which is different from the actual situation. Moreover, none of these methods can directly observe the instability process of tailings dam. In this paper, a tailings reservoir is used as engineering background, tailings are simulated as bulk materials, and the stability and instability process of the tailings reservoir under different working conditions are studied by using the particle flow discrete element software PFC2D under the premise of considering the distribution law of tailing sand in the reservoir. In this paper, the following aspects are completed: 1) sampling tailings at different distances from the tailings dam caving opening, and then analyzing the average particle size of each group of tailings by sieving test. The relationship between average particle size and distance is fitted, and the deposition rule of tailings in tailing reservoir is analyzed. Nine groups of microscopic parameters were designed by orthogonal design method, and then biaxial simulation tests were carried out on each group of samples by PFC2D software. The deflection stress-strain curves obtained from the simulation tests were obtained. The corresponding macroscopic parameters are calculated by the volume strain-axial strain curve and the Mole-Coulomb curve. Finally, through the range analysis of the macro parameters, the order of the influence degree of the micro parameters of different materials on the macro parameters is obtained. Based on the law of the influence of the micro parameters on the macro parameters, the bedrock in the tailings dam model is studied. The microcosmic parameters of the initial dam and the tailings are calibrated, and the macroscopic mechanical properties of the materials in the model are consistent with the actual conditions. (4) the PFC2D model of the tailings dam is established according to the law of tailings deposition in the tailings reservoir, and then based on the basic idea of the strength reduction method. The strength reduction function is compiled to obtain the safety factors of the tailings reservoir when the normal water level, flood water level and earthquake flood water level are simulated by PFC2D software, and the results are compared with those of the limit equilibrium method. The safety factor obtained by using PFC2D software is on the high side, which is mainly due to the influence of microcosmic parameters used by PFC2D software on many macro parameters at the same time. Moreover, there is no linear relationship between microscopic parameters and macroscopic parameters. (5) Monitoring circle is established in the tailings dam model, and the stress change inside the monitoring circle is monitored under the condition of strength reduction. By observing the stress change curve and the displacement of the particles in the model, the failure pattern and development process of tailings dam under different working conditions are analyzed. The failure slip surface of tailings dam under three working conditions is arc shape, the arc slip surface is the deepest under the special operation condition, the circular arc slip surface under the flood water level is the second, and the arc surface is the shallowest under the normal water level operation condition. The results are consistent with those obtained by the limit equilibrium method.
【學位授予單位】：昆明理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TD926.4

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本文編號：1930883