【摘要】：飽和尾礦的穩(wěn)態(tài)強(qiáng)度是尾礦壩能否發(fā)生流滑破壞的關(guān)鍵因素，因此，為了揭示尾礦壩流滑破壞機(jī)理，有必要先弄清尾礦的穩(wěn)態(tài)強(qiáng)度特性。動(dòng)荷載作用引起孔隙水壓力上升和土體有效應(yīng)力下降，而地震液化后發(fā)生的流滑破壞通常是由靜載荷引起的，故穩(wěn)態(tài)強(qiáng)度（或稱殘余強(qiáng)度）可在靜載條件下確定。 本文采用固結(jié)不排水三軸試驗(yàn)，通過配制6組不同相對(duì)密度的尾礦試樣，經(jīng)飽和后分別在100kPa、200kPa、300kPa的圍壓下進(jìn)行試驗(yàn)。在進(jìn)行剪切時(shí)保持圍壓不變，逐漸加大軸向剪切力。在剪切力達(dá)到最大值后，繼續(xù)進(jìn)行試驗(yàn)，當(dāng)試樣產(chǎn)生25%的軸向應(yīng)變時(shí)停止。另按照《土工試驗(yàn)方法標(biāo)準(zhǔn)》中的篩析法，以尾礦粒徑平均大小為變量，人工配制3種顆粒級(jí)配的尾礦試樣。在初始相對(duì)密度和圍壓一致的情況下，分別進(jìn)行固結(jié)不排水剪切試驗(yàn)，直至進(jìn)入穩(wěn)定狀態(tài)。 根據(jù)試驗(yàn)結(jié)果，繪制出不同圍壓、試樣密實(shí)度、顆粒級(jí)配下尾礦的應(yīng)力—應(yīng)變—孔隙水壓關(guān)系曲線，，建立飽和尾礦的穩(wěn)態(tài)線，求出尾礦的穩(wěn)態(tài)內(nèi)摩擦角及穩(wěn)態(tài)強(qiáng)度表達(dá)式。主要得到了以下研究成果： 飽和尾礦的固結(jié)不排水剪切曲線有三種典型類型：軟化型、準(zhǔn)軟化型、硬化型。其中飽和松散尾礦的剪切曲線具有明顯的軟化特性，試樣在軸向應(yīng)變?cè)鲩L(zhǎng)到15%—20%左右達(dá)到變形的穩(wěn)態(tài)。在剪切初期，軸向應(yīng)變及孔隙水壓隨著剪應(yīng)力的增大而增大。剪應(yīng)力達(dá)到峰值后隨之下降，最后保持穩(wěn)定，孔隙水壓力則在達(dá)到最大值后一直保持穩(wěn)定。 同一級(jí)配、同一孔隙比的試樣，隨著試驗(yàn)圍壓的增大，剪切曲線軟化程度逐漸降低，尾礦穩(wěn)態(tài)點(diǎn)則隨之上升。同一級(jí)配、不同孔隙比的試樣在200kPa圍壓下的剪切曲線均表現(xiàn)出應(yīng)變軟化，且隨著孔隙比的減小，剪切曲線的軟化程度逐漸減弱。 穩(wěn)態(tài)是尾礦的固有屬性，不受外界條件的影響，與尾礦的顆粒級(jí)配有關(guān)。在孔隙比與剪應(yīng)力的算術(shù)坐標(biāo)內(nèi)，尾礦的穩(wěn)態(tài)線是一條直線，線以上的部分，代表剪縮性尾礦，在實(shí)際情況下則有可能發(fā)生液化流滑。平均粒徑大的尾礦，其穩(wěn)態(tài)內(nèi)摩擦角大，穩(wěn)態(tài)線的空間分布位置高。因此，細(xì)粒尾礦在外力條件下更容易誘發(fā)液化流滑破壞。
[Abstract]:The steady-state strength of saturated tailings is the key factor for the failure of tailings dam. Therefore, in order to reveal the mechanism of fluid-slip failure of tailings dam, it is necessary to find out the steady strength characteristics of tailings. Dynamic load causes pore water pressure to rise and soil effective stress to decrease, but the flow slip failure after earthquake liquefaction is usually caused by static load, so the steady-state strength (or residual strength) can be determined under static load condition. In this paper, six groups of tailings samples with different relative densities were prepared by undrained triaxial test. After saturation, the tests were carried out under the confining pressure of 100kPa200kPa-300kPa respectively. The confining pressure is kept constant and the axial shear force is gradually increased. After the shear force reaches the maximum value, the test continues and stops when the specimen produces 25% axial strain. In addition, according to the sieve analysis method in the Standard of Geotechnical Test methods, three kinds of tailings samples with particle gradation were artificially prepared with the mean size of tailings as variables. Under the same initial relative density and confining pressure, the undrained shear tests were carried out respectively until they entered a stable state. According to the test results, the stress-strain-pore water pressure relationship curves of tailings with different confining pressures, sample compactness and particle gradation are drawn, the steady state curves of saturated tailings are established, and the steady state friction angles and steady strength expressions of tailings are obtained. The main results are as follows: there are three typical types of undrained shear curves of saturated tailings: softening type, quasi-softening type, and hardening type. The shear curve of saturated loose tailings has obvious softening characteristics, and the specimen reaches the steady state of deformation at the axial strain of 15% -20%. At the early stage of shear, the axial strain and pore water pressure increase with the increase of shear stress. When the shear stress reaches the peak value, it decreases and then keeps stable, while the pore water pressure remains stable after reaching the maximum value. With the increase of test confining pressure, the softening degree of shear curve decreases gradually, and the steady point of tailings increases with the increase of test confining pressure. The shear curves of samples with different porosity ratios show strain softening at 200kPa confining pressure, and the softening degree of shear curves decreases with the decrease of void ratio. Steady state is the inherent property of tailings, which is independent of external conditions and is related to the particle gradation of tailings. In the arithmetic coordinates of void ratio and shear stress, the steady state line of tailings is a straight line, the part above the line, representing shear-shrinkage tailings, may occur liquefaction flow slip in practice. The tailings with large average particle size have large steady state internal friction angle and high spatial distribution of steady state line. Therefore, fine tailings are more likely to induce liquefaction flow slip failure under external force.
【學(xué)位授予單位】：江西理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV649;TD926.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李全明;陳立宏;王云海;張興凱;;尾礦壩堆壩材料非線性力學(xué)特性試驗(yàn)研究及數(shù)學(xué)模型擬合[J];安全與環(huán)境學(xué)報(bào);2009年05期

2 徐進(jìn);張家生;李永豐;;某尾礦填料的土工試驗(yàn)研究[J];重慶建筑;2006年10期

3 尹光志;楊作亞;魏作安;譚欽文;;羊拉銅礦尾礦料的物理力學(xué)性質(zhì)[J];重慶大學(xué)學(xué)報(bào)(自然科學(xué)版);2007年09期

4 張千貴;尹光志;周永昆;敬小非;蔣長(zhǎng)寶;;尾礦粗細(xì)顆粒分層結(jié)構(gòu)體的力學(xué)特性分析[J];重慶大學(xué)學(xué)報(bào);2012年05期

5 徐宏達(dá);我國(guó)尾礦庫(kù)病害事故統(tǒng)計(jì)分析[J];工業(yè)建筑;2001年01期

6 余湘娟,姜樸,魏松;砂土的穩(wěn)態(tài)強(qiáng)度試驗(yàn)研究[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2001年01期

7 余湘娟,房震,嚴(yán)蘊(yùn),鄭紹軍,樓添良;震后飽和砂土的液化及邊坡穩(wěn)定問題述評(píng)[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2003年01期

8 曹林衛(wèi);彭向和;李德;呂振江;高翔;;變形場(chǎng)和滲流場(chǎng)耦合作用下的尾礦壩靜力穩(wěn)定性分析[J];重慶建筑大學(xué)學(xué)報(bào);2007年05期

9 余果;楊作亞;尹光志;劉超;;羊拉銅礦尾礦料動(dòng)力特性試驗(yàn)研究[J];重慶建筑大學(xué)學(xué)報(bào);2008年06期

10 魏勇;潘紅潔;郭利杰;;尾礦壩壩基管涌砂槽模型試驗(yàn)研究[J];金屬礦山;2011年08期

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