本文選題：離子型稀土　切入點(diǎn)：孔隙分布　出處：《江西理工大學(xué)》2017年碩士論文

【摘要】：本文以龍南地區(qū)離子型稀土礦體為研究對(duì)象,針對(duì)原地浸礦過(guò)程中出現(xiàn)的重點(diǎn)問(wèn)題,通過(guò)大量現(xiàn)場(chǎng)調(diào)研、測(cè)試和室內(nèi)試驗(yàn),對(duì)離子型稀土礦體的土水特性、孔隙分布、抗剪強(qiáng)度和蠕變特性進(jìn)行了較為系統(tǒng)的研究和探討,主要結(jié)論整理如下:(1)無(wú)論是原狀礦體還是重塑礦體,土-水特征曲線都具有相同的變化趨勢(shì),即礦體含水量隨基質(zhì)吸力的增大,經(jīng)歷穩(wěn)定不變、快速遞減和緩慢減小3個(gè)過(guò)程。通過(guò)土-水特征曲線實(shí)測(cè)數(shù)據(jù)函數(shù)擬合,得出FredlundXing模型是描述該類型離子型稀土礦體低吸力段的土-水特性的最佳模型。(2)孔隙比0.92的原狀礦體單位質(zhì)量礦體累積孔隙總體積為0.2345cm3/g,大孔隙(r≥5μm)、中孔隙(2μm≤r≤5μm)和小孔隙(r≤2μm)體積分別占孔隙總體積的58%、15%和27%;保持原狀礦體孔隙比重塑后,小孔隙體積增加約3.0%,表明相同孔隙比的原狀礦體和重塑礦體在孔隙分布上有明顯差異。而重塑為孔隙比0.97的礦樣,小孔隙體積減少約1.0%,孔隙分布基本達(dá)到原狀礦體狀態(tài)。(3)離子型稀土飽和礦體的應(yīng)力-應(yīng)變關(guān)系呈弱軟化型,稀土礦物顆粒的黏聚力對(duì)抗剪強(qiáng)度貢獻(xiàn)較小,礦體的抗剪強(qiáng)度主要由礦物顆粒之間的摩阻力承擔(dān);隨著基質(zhì)吸力增大,非飽和礦體的吸附強(qiáng)度呈非線性增加,應(yīng)力-應(yīng)變關(guān)系由硬化型逐漸轉(zhuǎn)變?yōu)槿踯浕?而基質(zhì)吸力的內(nèi)摩擦角φb呈非線性減小,表明基質(zhì)吸力對(duì)非飽和礦體抗剪強(qiáng)度的貢獻(xiàn)是有限的。利用乘冪函數(shù)對(duì)基質(zhì)吸力與吸附強(qiáng)度的關(guān)系進(jìn)行擬合,據(jù)此提出適合龍南類型離子型稀土非飽和礦體的抗剪強(qiáng)度公式和有效應(yīng)力表達(dá)式。(4)偏應(yīng)力水平不超過(guò)50%,礦樣主要產(chǎn)生衰減蠕變變形,且以瞬時(shí)彈性變形為主,蠕變變形量很小,礦樣處于穩(wěn)定狀態(tài);當(dāng)偏應(yīng)力水平達(dá)到70%,礦樣發(fā)生非穩(wěn)定蠕變,在經(jīng)歷減速蠕變和等速蠕變后,變形迅速發(fā)展,礦樣在短時(shí)間內(nèi)破壞。圍壓和含水率對(duì)離子型稀土礦體在加速蠕變階段的變形特征影響顯著,圍壓越小,礦樣越早出現(xiàn)加速蠕變階段,發(fā)生破壞的時(shí)間越短;含水率越大,礦樣破壞時(shí)變形量越大,強(qiáng)度降低越明顯�；谌渥�?cè)囼?yàn)數(shù)據(jù),分別探討B(tài)urgers模型、西原正夫模型以及冪函數(shù)模型的適用性,并且在Burgers模型基礎(chǔ)上引入非線性粘滯元件,建立一種新的非線性粘彈塑性模型,該模型能較好刻畫離子型稀土礦體蠕變?nèi)^(guò)程。
[Abstract]:In this paper, the ion type rare earth orebody in Longnan area is taken as the research object. Aiming at the key problems in the in-situ leaching process, the soil and water characteristics and pore distribution of the ion type rare earth ore body are studied through a large number of field investigations, tests and laboratory tests.The shear strength and creep characteristics are systematically studied and discussed. The main conclusions are as follows: (1) the soil-water characteristic curves have the same changing trend both in the original orebody and in the remolded orebody.That is, the water content of ore body goes through three processes: steady, fast decline and slow decrease with the increase of matrix suction.Through the function fitting of the measured data of soil-water characteristic curve,The volume of porosity 鈮，

本文編號(hào)：1710362