本文選題：軟弱夾層 + 應(yīng)變軟化��； 參考：《中國地質(zhì)大學(xué)》2017年博士論文

【摘要】：在我國堅持可持續(xù)發(fā)展和深入實施“西部大開發(fā)”的戰(zhàn)略決策中,礦產(chǎn)資源的合理開發(fā)和利用是非常重要的環(huán)節(jié)。我國中西部與西南地區(qū)湖北、湖南、四川、貴州、廣西、云南等省大范圍存在含緩傾軟弱夾層(巖層和夾層傾角均小于25°)的二疊系石灰?guī)r地層,該地層擁有豐富的優(yōu)質(zhì)石灰石礦產(chǎn)資源,是我國大量基礎(chǔ)設(shè)施建設(shè)的重要建材來源。隨著開采不斷向深部和高處進行,礦山所揭露的地層越來越多,所揭露的地層越來越復(fù)雜,面臨的礦山水文地質(zhì)條件也愈加復(fù)雜,加劇了對邊坡巖體的擾動,導(dǎo)致巖體力學(xué)性能劣化。各種軟弱地層的暴露、邊坡臨空面的擴展都嚴重影響著礦山邊坡的穩(wěn)定性和安全性。軟弱夾層由于其自身的特殊性,往往成為礦山邊坡的潛在滑動面,對礦山過程邊坡和終了邊坡的穩(wěn)定性起著控制作用。同時軟弱夾層也是水的良好的滲流通道,水巖作用加劇了夾層本身的力學(xué)性能的劣化,使軟弱夾層的流變特性愈發(fā)明顯。因此研究水對軟弱夾層的力學(xué)參數(shù)的劣化規(guī)律對礦山邊坡穩(wěn)定性評價和安全施工有至關(guān)重要的作用。本論文研究結(jié)合國家自然科學(xué)基金項目“降雨和爆破反復(fù)作用下高邊坡緩傾軟弱夾層的流變特性及其致滑機理研究”(41672317)和橫向項目“峨勝采礦場露采高陡邊坡穩(wěn)定性論證與優(yōu)化研究”,以四川峨勝礦區(qū)所揭露的二疊系茅口組含炭質(zhì)泥頁巖軟弱夾層為研究對象,考慮四川峨勝采礦區(qū)所處的水文地質(zhì)環(huán)境和氣象條件,對其進行不同含水率下常規(guī)環(huán)剪試驗、環(huán)剪蠕變試驗�；诔Ｒ�(guī)環(huán)剪試驗結(jié)果,探討了不同含水率下的軟弱夾層峰值強度和殘余強度的變化規(guī)律,進行了將含水率作為損傷變量的軟弱夾層力學(xué)參數(shù)劣化規(guī)律分析。開展不同含水率不同法向壓力下的環(huán)剪蠕變試驗,在對環(huán)剪蠕變試驗結(jié)果分析的基礎(chǔ)上,基于分數(shù)微積分提出了考慮軟弱夾層的含水率引起的流變模型參數(shù)變化作為損傷變量的非線性粘彈塑性流變本構(gòu)模型(DNMAP模型)。推導(dǎo)了DNMAP流變模型有限差分格式,采用FLAC3D二次開發(fā)平臺在Microsoft visual studio2010編程實現(xiàn)了新建本構(gòu)模型的二次開發(fā),并對其正確性和可行性進行了驗證。以二疊系茅口組軟弱夾層作為潛在滑動面的“1270-1380m”開挖平臺變形體為研究對象,對其進行了漸進性破壞分析及長期穩(wěn)定性預(yù)測,并提出了相應(yīng)的防治措施。本文取得的研究成果如下:(1)以四川峨勝采礦場“1270-1380m”開挖平臺出露的二疊系茅口組含炭質(zhì)泥頁巖軟弱夾層為研究對象,在分析其沉積環(huán)境和構(gòu)造環(huán)境的基礎(chǔ)上,分析了軟弱夾層的形成過程。利用礦物鑒定、X射線、激光粒度分布儀等手段對二疊系茅口組軟弱夾層的礦物成分、化學(xué)成分、粒徑組成等特征進行分析,并通過開展一系列物理力學(xué)試驗獲取了軟弱夾層的基本物理特性參數(shù)。研究表明:二疊系茅口組軟弱夾層礦物成分主要以粘土礦物、方解石為主。因粘土礦物的親水性較強,因此含水率對軟弱夾層的力學(xué)特性具有顯著的影響。(2)對二疊系茅口組軟弱夾層開展常規(guī)環(huán)剪試驗,研究了相同干密度不同含水率重塑軟弱夾層試樣在不同法向應(yīng)力作用下的剪切變形破壞特征。研究表明:法向應(yīng)力是影響軟弱夾層應(yīng)變硬化及軟化特性的重要因素。隨含水率及法向應(yīng)力的增大,較低法向應(yīng)力下表現(xiàn)應(yīng)變軟化特性的試樣,在環(huán)剪試驗過程中的法向位移特征表現(xiàn)為由剪脹為主轉(zhuǎn)變?yōu)榧艨s為主。高法向應(yīng)力下表現(xiàn)應(yīng)變硬化特性的試樣則表現(xiàn)出速率逐漸趨于穩(wěn)定的剪脹特性。環(huán)剪應(yīng)變特性受法向壓力和含水率的影響,法向壓力越大、含水率越高,試樣的應(yīng)變硬化特性越明顯。分析了含水率與法向應(yīng)力對于軟弱夾層峰值強度和殘余強度的影響規(guī)律,試驗結(jié)果顯示軟弱夾層試樣的峰值剪應(yīng)力、殘余剪應(yīng)力及其對應(yīng)的剪切位移均與試樣的含水率和法向應(yīng)力呈正相關(guān)關(guān)系。基于摩爾-庫侖強度準則與損傷力學(xué)原理研究了含水率對于軟弱夾層等效抗剪強度參數(shù)的損傷劣化規(guī)律,得到了抗剪強度參數(shù)損傷率與含水率的函數(shù)關(guān)系式。對試樣環(huán)剪破壞后的環(huán)剪面進行微觀電鏡掃描,討論了應(yīng)變軟化與應(yīng)變硬化試樣在微觀結(jié)構(gòu)上的差異性,并指出環(huán)剪試驗過程中顆粒位移、破碎與定向排列的差異是影響試樣宏觀力學(xué)特性的重要因素。(3)基于常規(guī)環(huán)剪試驗成果,對二疊系茅口組軟弱夾層開展不同含水率、不同法向壓力下的環(huán)剪蠕變試驗。對不同含水率下夾層試樣的剪切蠕變變形和應(yīng)變速率進行了分析。同時通過兩種方法確定了不同含水率下軟弱夾層的長期強度,并與殘余強度進行了對比。通過電鏡掃描對不同含水率試樣環(huán)剪蠕變破壞之后的破壞面進行了微觀特性分析。試驗結(jié)果表明:(1)在低于飽和含水率時,含水率越高,瞬時剪切應(yīng)變隨應(yīng)力等級的增加而變形增量變大;而高于飽和含水率之后,瞬時剪切應(yīng)變增量隨含水率的增加而呈現(xiàn)出降低的趨勢,增量最大值出現(xiàn)在飽和含水率附近。隨著含水率的增加,試樣累計蠕變增量也呈增大的趨勢。從蠕變曲線達到穩(wěn)態(tài)蠕變的變形量與瞬態(tài)彈性應(yīng)變的比值來看,隨著環(huán)剪應(yīng)力等級的增加,穩(wěn)態(tài)蠕變的變形量與瞬態(tài)彈性應(yīng)變的比值逐漸增加。應(yīng)力等級越大,蠕變變形量在總變形中的比重增大,蠕變特性表現(xiàn)得愈發(fā)明顯。(2)含水率對蠕變變形速率的規(guī)律性影響主要體現(xiàn)在對蠕變衰減段持續(xù)時間的影響上。研究表明,蠕變衰減持續(xù)時間隨含水率的改變大致呈線性變化規(guī)律。隨著應(yīng)力等級的增加,0.6倍的殘余應(yīng)力作用下擬合直線的斜率大于殘余應(yīng)力的擬合直線斜率。環(huán)剪應(yīng)力水平越高,蠕變衰減持續(xù)時間的增長率越緩。(3)等時應(yīng)力-應(yīng)變曲線法所確定的長期強度均大于穩(wěn)態(tài)蠕變速率法所確定長期強度,但量值相差不大。通過對不同含水率下夾層的長期強度與含水率的關(guān)系進行擬合分析,發(fā)現(xiàn)長期強度與含水率呈線性負相關(guān),含水率越高,軟弱夾層的長期強度越低。(4)不同含水率試樣在蠕變破壞之后的微觀特性存在著顯著差異,含水率較低的試樣,破壞面光滑,變形擦痕較為清晰,片狀結(jié)構(gòu)明顯;隨著含水率的升高,試樣逐漸軟化,由于試樣含有膨脹性的粘土礦物,顆粒由于膨脹性變強排列變得致密,各向同性明顯。由于試樣破壞前變形量變大,破壞面上多空隙和裂縫出現(xiàn),表現(xiàn)出延性破壞特征。(4)詳細介紹了分數(shù)階微積分的幾種常用定義,并基于分數(shù)階微積分對現(xiàn)有的幾種常見流變元件模型進行了改進,分別給出了蠕變本構(gòu)方程。通過對飽和狀態(tài)下軟弱夾層試樣蠕變破壞前試驗曲線的擬合,綜合考慮各種因素選取基于分數(shù)階微積分改進的Maxwell元件模型作為新建蠕變本構(gòu)模型的粘彈性部分。同時,分析發(fā)現(xiàn)非定常參數(shù)Abel粘壺能夠描述蠕變加速破壞段的特性,因此將其與塑性元件并聯(lián)組合成粘塑性體與前面改進Maxwell元件模型串聯(lián)構(gòu)建了一種新的非線性剪切蠕變本構(gòu)模型(NMAP),對其蠕變本構(gòu)方程進行了推導(dǎo)。通過對試樣環(huán)剪蠕變加速破壞段的擬合發(fā)現(xiàn),新建立的NMAP元件本構(gòu)模型能夠很好地擬合蠕變?nèi)^程試驗曲線。(5)基于損傷理論將軟弱夾層的含水率引起的流變模型參數(shù)變化作為損傷變量引入到NMAP模型中,建立了考慮含水率損傷的非線性黏彈塑性剪切流變本構(gòu)模型DNMAP模型。通過對環(huán)剪蠕變試驗結(jié)果曲線的擬合,可以看出DNMAP模型對不同含水率試樣蠕變?nèi)^程特別是對加速蠕變階段具有良好的擬合效果。(6)對新建立的非線性黏彈塑性本構(gòu)模型(DNMAP)進行了詳細的公式推導(dǎo),對其蠕變本構(gòu)方程進行三維差分形式離散,得到了應(yīng)力增量的差分表達式。利用FLAC3D內(nèi)置的FLAC3D500VS2010Addin.msi插件,在Visual studio2010軟件中實現(xiàn)了基于分數(shù)階微積分的新建蠕變本構(gòu)模型的開發(fā)。并通過建立一個三維數(shù)值計算模型,來模擬計算其單軸壓縮蠕變試驗結(jié)果,證明了新建DNMAP損傷流變本構(gòu)模型的合理性,也說明其在FLAC3D中的二次開發(fā)實現(xiàn)過程的正確性。(7)在介紹峨勝礦區(qū)“1270-1380m”平臺變形體的基本地質(zhì)條件和地質(zhì)環(huán)境基礎(chǔ)上,考慮軟弱夾層的應(yīng)變軟化和流變特性,對變形體進行了漸進性破壞分析和長期穩(wěn)定性預(yù)測研究。在對變形體進行漸進性破壞分析時,分別采用了極限平衡法和基于應(yīng)變軟化模型的容重增加法。結(jié)果表明:容重增加法計算所得到的穩(wěn)定狀態(tài)的安全系數(shù)要略大于極限平衡法運用殘余強度所得的安全系數(shù)。將容重增加法數(shù)值計算過程中不同時步下的剪應(yīng)變增量分布的變化趨勢來表示變形體的漸進性破壞的發(fā)展過程。剪應(yīng)變增量經(jīng)歷從出現(xiàn)、擴展直至穩(wěn)定的過程。當(dāng)計算時步達到一定值時,剪應(yīng)變增量分布趨于穩(wěn)定,邊坡安全系數(shù)也不再發(fā)生變化�；谶吰挛灰品捶治龇ɡ眠z傳算法和神經(jīng)網(wǎng)絡(luò)對流變模型參數(shù)進行了反演,通過實測值和計算值的對比證明了反演參數(shù)的合理性以及本文所提出的DNMAP蠕變本構(gòu)模型的正確性。通過對變形體位移變化和剪應(yīng)變增量的計算對其穩(wěn)定性發(fā)展趨勢進行了預(yù)測。
[Abstract]:The rational exploitation and utilization of mineral resources is a very important link in our country's insistence on sustainable development and the deep implementation of the strategic decision of "the development of the west". In the central and western regions of China, Hubei, Hunan, Sichuan, Guizhou, Guangxi, Yunnan, and other provinces, there are slow soft layers (rock layers and interlayer dip angles are less than 25 degrees). The Permian limestone strata, which have rich mineral resources of high quality limestone, are an important source of building materials in the construction of a large number of infrastructure in China. With the continuous exploitation of mining to the deep and high places, more and more strata are exposed in the mine, the exposed strata are becoming more and more complex, and the hydrogeological conditions facing the mine are becoming more complex and added. The disturbance of the slope rock mass leads to the deterioration of the mechanical properties of rock mass. The exposure of various soft strata and the expansion of the side surface of the slope seriously affect the stability and safety of the mine slope. Because of its own particularity, the weak interlayer often becomes the potential sliding surface of the mine slope, and the stability of the mine process slope and the end slope. At the same time, the weak interlayer is also a good seepage channel for water. The water rock action aggravates the deterioration of the mechanical properties of the interlayer and makes the rheological properties of the soft interlayer become more obvious. Therefore, it is very important to study the deterioration law of the mechanical parameters of the soft intercalation to the stability evaluation and safety construction of the mine slope. In this paper, the paper studies the rheological properties and slippery mechanism of the gentle dip and soft intercalation of high slope under the action of rainfall and blasting repeatedly under the National Natural Science Foundation of China (41672317) and the lateral project "demonstration and optimization of the stability of the high and steep slope in the Emei mining field", the Permian system of the Emei mine in Sichuan The soft interlayer of carbonaceous shale in Makou formation is the research object. Considering the hydrogeological environment and meteorological conditions in Sichuan Emei mining area, the conventional ring shear test and cyclic shear creep test under different water content are carried out. Based on the results of conventional ring shear test, the variation of peak strength and residual strength of weak intercalation under different water content is discussed. The deterioration law of the mechanical parameters of the soft interlayer with water content as the damage variable is analyzed. The cyclic shear creep test under different normal pressure of different water content is carried out. On the basis of the analysis of the cyclic shear creep test results, the rheological model parameters, which are caused by the water content of the soft and weak interlayer, are put forward based on the fractional calculus. The nonlinear viscoelastic plastic rheological constitutive model (DNMAP model) is used as the damage variable. The finite difference scheme of the DNMAP rheology model is derived. The two development of the new constitutive model is realized by the FLAC3D two development platform in Microsoft visual studio2010 programming, and its correctness and feasibility are verified. As the research object of the "1270-1380m" excavated platform deformation body of the potential sliding surface, the weak interlayer is studied, the progressive failure analysis and the long-term stability prediction are carried out, and the corresponding prevention and control measures are put forward. The results obtained in this paper are as follows: (1) the Permian Makou in the Sichuan Emei mining field "1270-1380m" excavation platform On the basis of the analysis of the sedimentary environment and the tectonic environment, the formation process of soft intercalation was analyzed on the basis of the analysis of the sedimentary environment and the tectonic environment. The mineral composition, chemical composition and particle size composition of the Permian Maogu group were analyzed by means of mineral identification, X ray and laser particle size distribution instrument. A series of physical and mechanical tests have been carried out to obtain the basic physical parameters of soft intercalation. The study shows that the mineral composition of the soft interlayer of the Maogu group of the Permian is mainly clay minerals and calcite. The hydrophilicity of the clay minerals is stronger, so the water content has a significant influence on the force characteristics of the weak intercalation. (2) the Permian Permian. The shear deformation failure characteristics of the soft interlayer with the same dry density and different moisture content under the action of different normal stress are studied. The study shows that the normal stress is an important factor affecting the strain hardening and softening characteristics of the weak intercalation. The increase of water content and normal stress is the lower method. Specimens with strain softening under stress are characterized by shear dilatancy as the main shear shrinkage during the ring shear test, and the shear dilatancy characteristics of the specimens showing strain hardening under high normal stress show that the shear strain characteristics are influenced by normal pressure and water content. The greater the pressure is, the higher the water content is, the more obvious the strain hardening characteristic of the specimen is. The influence of water content and normal stress on the peak strength and the residual strength of the weak intercalation is analyzed. The test results show the peak shear stress, the residual shear stress and the corresponding shear displacement are all with the moisture content and normal stress of the specimen. Based on the Moore Coulomb strength criterion and the principle of damage mechanics, the damage and deterioration law of water content to the equivalent shear strength parameters of weak intercalation is studied, and a function relation between the damage rate and water content of the shear strength parameters is obtained. The microscopic scanning of the ring shear surface after the ring shear failure of the sample is carried out and the strain softening is discussed. The difference between the strain hardening and the strain hardening specimens on the microstructure, and points out that the difference between the particle displacement, the breakage and the directional arrangement in the ring shear test is an important factor affecting the macroscopic mechanical properties of the specimens. (3) based on the conventional ring shear test results, the water content of the soft interlayer of the Permian Makou formation and the ring shear creep under the different normal pressure are carried out. The shear creep deformation and the strain rate of the sandwich specimens with different water content were analyzed. At the same time, the long-term strength of the weak intercalation under different water content was determined by two methods, and the comparison with the residual strength was made. The experimental results show that (1) when the water cut is lower than the saturated water content, the higher the water cut is, the increase of the instantaneous shear strain increases with the increase of the stress level, and the increment of instantaneous shear strain increases with the increase of water content, and the maximum increment appears near the saturated water content. With the increase of water content, the cumulative creep increment of the specimen is also increasing. From the creep curve to the ratio of the steady creep deformation and the transient elastic strain, the ratio of the steady creep deformation and the transient elastic strain increases with the increase of the cyclic shear stress grade. The higher the stress grade, the creep deformation is in the total deformation. The specific gravity in the creep is more obvious. (2) the influence of water content on the creep deformation rate is mainly reflected on the duration of the creep decay period. The study shows that the creep decay duration is approximately linear with the change of water content. With the increase of the stress grade, the residual stress is 0.6 times. The slope of the fitting line is greater than the fitting line slope of the residual stress. The higher the stress level of the ring shear stress, the slower the growth rate of the creep decay duration. (3) the long-term strength determined by the isochronous stress strain curve method is greater than that determined by the steady creep rate method, but the difference of the value is small. The relationship between the long-term strength and water content of the layer is fitted and analyzed. It is found that the long-term strength and water content have a linear negative correlation. The higher the water content, the lower the long-term strength of the weak intercalation. (4) there is a significant difference in the microscopic characteristics of the specimens with different water content after the creep damage, and the specimen with lower water content is smooth and the deformation scratch is more. It is clear and flaky structure is obvious; with the increase of water content, the sample softens gradually. Because the sample contains expansive clay minerals, the particle becomes denser and isotropic as the expansibility becomes stronger and the isotropy is obvious. Due to the large deformation measurement before the specimen is destroyed, the fracture surface has many gaps and cracks, showing the characteristics of ductility damage. (4) detailed introduction Several common definitions of fractional calculus are used, and some existing rheological element models are improved based on fractional calculus. The creep constitutive equations are given respectively. By fitting the test curves before the creep failure of the soft interlayer under saturated state, a variety of factors are taken into consideration to improve the fractional calculus. The Maxwell element model is the viscoelastic part of the new creep constitutive model. At the same time, it is found that the unsteady parameter Abel pot can describe the characteristics of the creep accelerated failure section. Therefore, a new nonlinear shear creep constitutive model is constructed in parallel with the plastic element and the front improved Maxwell element model. The constitutive model (NMAP) is used to derive the creep constitutive equation. Through the fitting of the accelerated failure section of the specimen ring shear creep, it is found that the newly established NMAP element constitutive model can well fit the whole creep test curve. (5) based on the damage theory, the change of the rheological model parameters caused by the water content of the weak interlayer is used as the damage variable. In the NMAP model, a nonlinear viscoelastic plastic shear rheological constitutive model DNMAP model is established to consider the damage of water content. By fitting the curve of the cyclic shear creep test results, it can be seen that the DNMAP model has a good fitting effect on the whole creep process of different moisture content specimens, especially for the accelerated creep stage. (6) the new model is established. The nonlinear viscoelastic plastic constitutive model (DNMAP) is derived in detail, and its creep constitutive equation is discrete in three dimensional difference form, and the differential expression of stress increment is obtained. A new creeping version based on fractional calculus is realized in Visual studio2010 software by using the built-in FLAC3D500VS2010Addin.msi plug-in of FLAC3D. A three-dimensional numerical model is developed to simulate and calculate the results of the uniaxial compression creep test, which proves the rationality of the new DNMAP damage rheological constitutive model and the correctness of its two development process in FLAC3D. (7) the basic of the "1270-1380m" deformable body in the Emei mining area is introduced. On the basis of geological conditions and geological environment, considering the strain softening and rheological properties of weak intercalation, the progressive failure analysis and long-term stability prediction of the deformable bodies are studied. The limit equilibrium method and the bulk density increase method based on the strain softening model are adopted respectively in the analysis of the progressive failure of the deformable body. The safety factor of the stable state obtained by the heavy increase method is slightly greater than the safety factor of the residual strength of the limit equilibrium method. The progressive failure of the deformation body is represented by the trend of the variation trend of the shear strain increment in the numerical calculation process. The shear strain increment experience is from the emergence. When the calculation step reaches a certain value, the increment distribution of shear strain tends to be stable and the safety factor of slope no longer changes. Based on the inverse analysis method of slope displacement, the parameters of the rheological model are retrieved by the genetic algorithm and neural network, and the inverse parameters are proved by the comparison of the actual and calculated values. Rationality and the correctness of the DNMAP creep constitutive model proposed in this paper. The trend of its stability is predicted by the change of deformation position and the calculation of shear strain increment.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TD31
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本文編號：2056013