本文關(guān)鍵詞：干濕循環(huán)作用下尾礦砂物理力學(xué)特性研究　出處：《南華大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 尾礦砂 干濕循環(huán) 力學(xué)特性 穩(wěn)定性

【摘要】：由于降水入滲、水分蒸發(fā)、浸潤線上升和下降等原因,使尾礦長期處于一種循環(huán)的吸濕-脫濕狀態(tài),在干濕循環(huán)過程中尾礦砂的物理力學(xué)特性變化機(jī)制,關(guān)系到整個(gè)尾礦壩的安全運(yùn)行。因此,本文以湖南省內(nèi)某尾礦壩為研究對象,采用現(xiàn)場取樣、室內(nèi)模擬試驗(yàn)的方式展開研究,首先對尾礦砂的基本物理力學(xué)參數(shù)進(jìn)行測試,然后利用自制的分層取樣試驗(yàn)裝置模擬尾礦砂的干濕循環(huán)過程,對經(jīng)歷干濕循環(huán)過程的尾礦砂物理力學(xué)參數(shù)變化進(jìn)行了詳細(xì)研究分析,并采用強(qiáng)度折減法基本原理結(jié)合數(shù)值模擬軟件ABAQUS,對經(jīng)歷干濕循環(huán)作用后尾礦壩的穩(wěn)定性影響進(jìn)行分析。本文的主要研究成果和結(jié)論有:(1)在干濕循環(huán)試驗(yàn)過程中,發(fā)現(xiàn)在不同的干濕循環(huán)次數(shù)下相同的含水率對應(yīng)不同的基質(zhì)吸力,尾礦砂的土-水特征曲線出現(xiàn)滯回效應(yīng),并且這種變化在前3次干濕循環(huán)過程中變化最大,隨著干濕循環(huán)過程的繼續(xù),土-水特征曲線逐漸趨于穩(wěn)定。(2)對尾礦砂在不同干濕循環(huán)次數(shù)時(shí)的土水特征曲線進(jìn)行擬合,得到了干濕循環(huán)作用下尾礦砂土-水特征曲線的預(yù)測模型。(3)在干濕循環(huán)作用下,尾礦砂的抗剪強(qiáng)度隨著干濕循環(huán)次數(shù)的增加逐漸降低,干濕循環(huán)4次以后尾礦砂的抗剪強(qiáng)度趨于穩(wěn)定。強(qiáng)度的變化主要表現(xiàn)在強(qiáng)度參數(shù)內(nèi)摩擦角和黏聚力的變化,隨著干濕循環(huán)的進(jìn)行尾礦砂的內(nèi)摩擦角逐漸減小最終趨穩(wěn)定,粘聚力也逐漸降低最終趨于穩(wěn)定。內(nèi)摩擦角隨著干濕循環(huán)次數(shù)的最初衰減幅度要比粘聚力的衰減幅度大。(4)在干濕循環(huán)作用下,基質(zhì)吸力為10kap尾礦砂的抗剪強(qiáng)度大于基質(zhì)吸力為15kap時(shí)尾礦砂的抗剪強(qiáng)度,并且隨著干濕循環(huán)次數(shù)的增加,在高應(yīng)力狀態(tài)下,基質(zhì)吸力對尾礦砂抗剪強(qiáng)度的增大和減小的影響也會發(fā)生變化。(5)尾礦壩的安全系數(shù)隨著干濕循環(huán)作用進(jìn)行逐漸減低,在前3次干濕循環(huán)過程中尾礦壩的安全系數(shù)衰減速度較快,隨后的衰減速度逐漸趨于穩(wěn)定。在整個(gè)干濕循環(huán)過程中,尾礦壩的穩(wěn)定性系數(shù)由2.05下降到1.70,整體下降幅度達(dá)到17.1%。同時(shí)也說明了干濕循環(huán)作用對尾礦壩的穩(wěn)定性具有一定的影響。
[Abstract]:Because of the reasons of precipitation infiltration, water evaporation, rising and falling of seepage line and so on, tailings are in a state of cyclic moisture absorption and dehumidification for a long time. During the dry wet cycle, the mechanism of physical and mechanical characteristics of tailings is related to the safe operation of the whole tailings dam. Therefore, in this paper, a tailings dam in Hunan Province as the research object, studied by field sampling, indoor simulation test, first the basic physical and mechanical parameters of tailings were tested, and then use stratified sampling experiments simulating the tailings dry wet cycle process, the physical and mechanical parameters of tailings of wetting and drying cycles the detailed research and analysis, and the basic principle of the strength reduction method combined with numerical simulation software ABAQUS, the influence of tailings dam stability analysis through dry wet cycles. The main research results and conclusions of this paper are: (1) in the dry wet cycle test, found in water cycle corresponding to different under the same rate of different matric suction, water characteristic curve of tailings sand soil appeared hysteresis effect, and the change in the first 3 dry wet cycle process, the biggest change, with the continued cycle of dry and wet process, the soil water characteristic curve tends to be stable. (2) fitting the soil water characteristic curve of tailings under different cycles of wetting and drying cycles, the prediction model of soil water characteristic curve of tailings sand under dry wet cycling is obtained. (3) under the action of dry wet cycle, the shear strength of tailings decreases with the increase of dry and wet cycles. After 4 cycles of dry and wet cycling, the shear strength of tailings becomes stable. The change of strength is mainly manifested in the variation of internal friction angle and cohesive force of strength parameters. With the dry wet cycle, the internal friction angle of tailings decreases gradually, and finally becomes stable and cohesive force gradually decreases, and finally tends to be stable. The initial attenuation amplitude of the internal friction angle with the number of dry and wet cycles is larger than that of the cohesive force. (4) in the wet and dry cycle, matrix suction as the shear strength of 15kap is greater than the suction shear strength of 10kap tailings tailings, and with the increase of cycle times, in high stress state, the matrix suction effect of shear strength increase and decrease will change on the anti tail ore. (5) the safety factor of tailings dam decreases with the action of drying and wetting. In the first 3 dry and wet cycles, the safety factor of tailings dam decays faster, and then the attenuation speed gradually becomes stable. During the whole dry and wet cycle, the stability coefficient of the tailings dam decreased from 2.05 to 1.70, and the overall decline was 17.1%. It also shows that the effect of dry and wet circulation on the stability of tailings dam has a certain influence.
【學(xué)位授予單位】：南華大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TD926.4

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