本文選題：秦巴山區(qū) + 千枚巖斜坡�。� 參考：《長安大學》2015年碩士論文

【摘要】：秦巴山區(qū)位于我國中西部地區(qū),區(qū)域內(nèi)地質(zhì)條件復雜,地形起伏顯著,斷裂發(fā)育,巖體破碎風化嚴重,降水豐富,工程活動活躍,是我國地質(zhì)災害多發(fā)地區(qū)之一。陜南秦巴山區(qū)變質(zhì)巖斜坡分布廣泛,巖性以千枚巖、板巖、片巖等為主,其中千枚巖斜坡以其多節(jié)理、強度低、風化嚴重等特點為秦巴山區(qū)典型代表斜坡。在自然和人為因素影響下,千枚巖斜坡頻頻發(fā)生滑坡、崩塌等災害,對當?shù)厝嗣裆钤斐芍卮蟀踩[患。因此,開展千枚巖斜坡變形破壞機制研究對秦巴山區(qū)千枚巖滑坡災害防治具有重要意義。本論文以秦巴山區(qū)順層千枚巖斜坡為研究目標,選取旬陽縣堯柏水泥廠滑坡為典型研究對象,通過滑坡測繪與勘察確定其典型剖面、巖體結構、地質(zhì)構造等工程地質(zhì)條件和滑坡物質(zhì)組成、變形破壞等特征。以堯柏水泥廠滑坡為原型開展室內(nèi)物理模型試驗,分別探究長期重力作用、不同層面組合、不同節(jié)理組合和坡腳開挖對千枚巖斜坡順層破壞的作用機制,并對試驗進行數(shù)值模擬,分析四種工況下斜坡的變形破壞特征、應力發(fā)展規(guī)律和破壞模式,以此建立坡體在整體式滑動破壞中的不穩(wěn)定巖體長度的計算模型和千枚巖邊坡穩(wěn)定性與軟弱面埋深的關系模型。模型試驗中采用自行開發(fā)的非接觸式位移監(jiān)測系統(tǒng),監(jiān)測模型中所有可視巖塊的位移數(shù)據(jù),并及時記錄邊坡變形破壞的運動形態(tài)。最后,采用三維離散元軟件3DEC模擬堯柏水泥廠滑坡的變形破壞,分析坡體在初始破壞階段的變形、應力演化、應變累積特征以及滑動破壞過程中坡體的位移變化規(guī)律,揭示出滑坡以“滑移-拉裂”為主的順層破壞機理,破壞過程表現(xiàn)出漸進破壞的特征。通過上述研究,本文取得以下成果:(1)堯柏水泥廠千枚巖斜坡滑動破壞受地形地貌、巖性組合、地質(zhì)構造等自然因素和人類工程活動等外在因素影響。自然因素從本質(zhì)上決定原始坡體的易滑性,坡腳開挖則作為誘發(fā)條件導致坡體的滑動破壞。坡腳開挖造成坡體中前部最大和最小主應力分別增大和減小,淺表層甚至出現(xiàn)“拉-壓”應力組合,坡體在此應力組合下沿節(jié)理面壓致拉裂;坡腳出現(xiàn)剪應力集中,剪應力集中條帶逐漸發(fā)展為滑移帶,最終發(fā)生“滑移-拉裂”漸進式破壞;(2)滑坡模型試驗和三維數(shù)值模擬顯示,層面強度、結構面組合以及坡腳開挖方式等影響千枚巖邊坡變形破壞規(guī)律。軟弱面加速坡體的滑動破壞,控制坡體的滑動面和破壞模式,使其具有整體滑動破壞的特征,坡體穩(wěn)定系數(shù)隨軟弱面埋深增大而降低并最終保持最小穩(wěn)定系數(shù);結構面傾向與坡向的夾角影響邊坡穩(wěn)定性,夾角在20-30°時,坡體穩(wěn)定性較高,不利結構面的傾向使坡體破壞具有“左旋性”特征;分級開挖坡腳后坡體滑動破壞具有“滯后性”,以“滑移-拉裂”整體式破壞為主;整體開挖后坡體滑動破壞則具有“迅速性”,以“滑移-拉裂”漸進式破壞為主;(3)采用極限平衡法,分別建立適用于整體式滑移破壞的不穩(wěn)定巖體臨界長度計算模型和千枚巖斜坡穩(wěn)定系數(shù)與軟弱面埋深的關系模型。前者表明不穩(wěn)定巖體臨界長度主要受層面強度、節(jié)理面抗拉強度、巖體密度、巖層傾角以及巖層厚度等控制;后者表明坡體穩(wěn)定系數(shù)隨軟弱面埋深的增大而降低,最終降低為最小穩(wěn)定系數(shù)Fs,min,Fs,min與軟弱面摩擦角呈正相關,與巖層傾角呈負相關;(4)順層千枚巖斜坡破壞模式包括“滑移-拉裂”漸進式破壞和“滑移-拉裂”整體式破壞。前者破壞機制為“蠕變-拉裂-滑移-拉裂-滑移”的累進破壞過程;后者破壞機制為“蠕變-拉裂-剪切-滑移”的整體破壞過程。
[Abstract]:Qinba mountain area is located in the central and western regions of China. The geological conditions are complex, the terrain is undulating, fracture development, rock mass breakage and weathering, heavy rainfall, and active engineering activities. The slope of metamorphic rock in Qinba mountain area of Southern Shaanxi is widely distributed, lithology is mainly phyllite, slate and schist. Under the influence of natural and man-made factors, the slope of the phyllite slopes frequently, such as landslides and collapses, caused by the natural and man-made factors, causing major safety hazards to the people of the local people. Therefore, the study of the mechanism of the phyllite slope deformation and destruction to the phyllite in Qinba Mountain Area is slippery. The prevention and control of slope disaster is of great significance. In this paper, taking the bedding phyllite slope in Qinba mountain area as the research target, the landslide of Yao Bai cement plant in Xunyang county is selected as the typical research object, and the typical section, rock mass structure, geological structure and other characteristics of the landslide material composition, deformation and damage, etc. are determined by landslide surveying and surveying. The physical model test of the landslide in the Bai cement factory is carried out as a prototype. The mechanism of the long-term gravity action, the combination of different layers, the combination of different joints and the slope foot excavation on the failure of the phyllite slope is investigated, and the numerical simulation is carried out to analyze the characteristics of the deformation and failure of the slope under the four conditions, the law of stress development and the failure mode. In order to establish the calculation model of the unstable rock length of the slope in the overall sliding failure and the relationship model of the stability of the phyllite slope and the buried depth of the soft surface. In the model test, the self developed non-contact displacement monitoring system is used to monitor the displacement data of all the visible rocks in the model and to record the deformation and failure of the slope in time. In the end, the deformation and failure of landslide in Yao Bai cement plant are simulated by the three-dimensional discrete element software 3DEC, and the deformation, stress evolution, strain accumulation and displacement of the slope during the initial failure stage are analyzed, and the failure mechanism of the landslide in the sliding failure process is revealed, and the failure mechanism of the landslide is mainly "slip and pull", and the failure of the landslide is revealed. The following results are obtained: (1) the sliding failure of the phyllite slope in the Yao Bai cement plant is influenced by the natural factors such as topography, lithology combination, geological structure and other natural factors such as the human engineering activities. The maximum and minimum main stress in the front part of the slope increases and decreases, and the shallow surface even appears the "pull pressure" stress combination, and the slope body is pressed to crack along the joint under this stress combination, the slope foot appears shear stress concentration, and the shear stress concentrating strip gradually develops into slip zone. Finally, "slip and pull" progressive failure occurred. (2) the landslide model test and three-dimensional numerical simulation show that the deformation and failure laws of the phyllite slope are affected by the strength of the plane, the combination of the structure surface and the way of the slope excavation. The sliding failure of the soft surface acceleration slope, the sliding surface and the failure mode of the slope are controlled, so that it has a whole sliding failure. Characteristic, the slope stability coefficient decreases with the burial depth of the soft surface and eventually maintains the minimum stability coefficient; the angle between the structure surface and the slope affects the slope stability. The slope body stability is higher when the angle is 20-30 degrees. The inclination of the unfavorable structure surface makes the slope failure have the "left rotation" characteristic, and the sliding failure tool of the rear slope body after the grade excavation slope is broken. There is "lag", which is mainly "slip and crack" failure. The sliding failure of the slope body after the whole excavation is "quick" and "slip and pull" progressive failure mainly. (3) the critical length calculation model of unstable rock mass suitable for holistic slip failure and the stability of phyllite slope are established by the limit equilibrium method. The former shows that the critical length of the unstable rock mass is mainly controlled by the strength of the layer, the tensile strength of the joint surface, the density of rock mass, the dip angle of the rock and the thickness of the rock layer, and the latter indicates that the slope stability coefficient decreases with the increase of the depth of the soft surface, and finally reduces to the minimum stability coefficient Fs, min, Fs, min and weakness. There is a positive correlation between the surface friction angle and the rock dip angle; (4) the failure mode of the CIS phyllite slope includes "slip and pull" progressive failure and "slip and pull". The former failure mechanism is the progressive failure process of "creep crack sliding crack sliding", and the latter failure mechanism is "creep splitting shear shear slip". The whole process of destruction.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P642.2

【引證文獻】

相關會議論文 前2條

1 周迎慶;王蘭生;;順層斜坡的巖體滲透性及水動力學特征研究[A];第四屆全國工程地質(zhì)大會論文選集（二）[C];1992年

2 徐邦棟;;巖石順層滑坡的某些性質(zhì)與地質(zhì)構造間的關系及其防治[A];全國首屆工程地質(zhì)學術會議論文選集[C];1979年

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本文編號：2097948