本文選題：力學參數　切入點：模型試驗　出處：《重慶交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：三峽水庫運行期間，庫水位每年在145~175m間周期性循環(huán)升降，庫水對岸坡巖土體形成了周期性浸泡，劣化庫岸巖土體的抗剪強度，打破了現有岸坡的穩(wěn)定性，造成庫岸邊坡的失穩(wěn)，因此水庫運行過程中岸坡穩(wěn)定性變化規(guī)律及其破壞機制研究成為一個重要的研究課題。論文以三峽庫區(qū)神女溪青石滑坡為背景，采用室內試驗分析、數值模擬及理論分析相結合的方法，分析神女溪岸坡失穩(wěn)的影響因素，并結合模型試驗再現該岸坡破壞過程，通過數值模擬對其進行滲流場、位移場分析，獲取該岸坡穩(wěn)定性變化規(guī)律，并建立該岸坡突發(fā)性破壞機制，主要取得了以下成果： （1）現場調研選取神女溪青石滑坡不同高程處土體，采用篩分試驗、X衍射光譜分析、剪切試驗等方法，分析同一岸坡不同高程處土體在庫水作用下粒度、礦物成分及土體力學參數的變化特性，得到了神女溪青石滑坡土體強度主要受含水量影響。 （2）以神女溪青石滑坡為原型，依據相似理論，建立三峽水庫神女溪岸坡破壞機制地質試驗模型。擬定庫水位升降變化試驗工況，通過模型試驗，得到岸坡不同高程處孔隙水壓力數據及坡體裂縫情況，分析坡體在整個試驗過程中的破壞現象，并得出孔隙水壓力變化和地下水位變動是影響坡體破壞的主導誘因。 （3）根據飽和-非飽和理論，結合試驗模型，采用Midas/GTS數值模擬軟件，模擬模型坡體滲流場變化來驗證試驗所得數據；同時模擬神女溪青石滑坡，獲取了水庫運行過程中岸坡滲流場、位移場和剪應變增量圖演變趨勢：水位上升階段，岸坡孔隙水壓力呈上升趨勢，坡腳首先出現位移；水位下降階段，岸坡孔隙水壓力呈下降趨勢，其靠近滑面處位移量逐漸增加，直至貫通。 （4）應用Midas/GTS采用強度折減法獲取的穩(wěn)定系數與地災規(guī)范算出的穩(wěn)定系數基本吻合，，通過數值模擬及穩(wěn)定性計算分析出神女溪青石岸坡在蓄水位期間，岸坡穩(wěn)定性先略微增加后降低。 （5）根據地貌演化特征，結合地勘資料提供的變形數據，從神女溪青石滑坡坡腳軟化階段，下部坍塌帶動上部蠕動階段，岸坡后部拉裂階段，整體下滑階段四個破壞過程進行分析。基于神女溪青石滑坡地質結構，將145m水位以下部位假定為應變軟化區(qū)段，145m至175m區(qū)段假定為彈性區(qū)段；以突變理論、能量原理為基礎，構建該岸坡破壞尖點突變力學模型，揭示該類岸坡次級滑坡突發(fā)性破壞機制。
[Abstract]:During the operation of the three Gorges Reservoir, the water level of the reservoir rises and rises periodically between 145m and 175m each year, and the reservoir water periodically immerses the rock and soil on the bank, which results in the deterioration of the shear strength of the rock and soil on the bank of the reservoir, which breaks the stability of the existing bank slope and results in the instability of the bank slope of the reservoir. Therefore, the study of slope stability and its failure mechanism has become an important research subject during the operation of the reservoir. Based on the Shennexi Qingshi landslide in the three Gorges Reservoir area, the laboratory test analysis is adopted. With the method of numerical simulation and theoretical analysis, the influencing factors of slope instability in Shennu River are analyzed, and the failure process of bank slope is reappeared by model test. The seepage field and displacement field are analyzed by numerical simulation. The variation law of the slope stability is obtained, and the sudden failure mechanism of the bank slope is established. The main achievements are as follows:. 1) the soil mass at different elevation of Qingshi landslide in Shennexi is selected, and the particle size of soil at different elevation on the same bank slope under the action of reservoir water is analyzed by means of screening test, X-ray diffraction spectrum analysis and shear test. The change characteristics of mineral composition and soil mechanical parameters show that the soil strength of Shennexi Qingshi landslide is mainly affected by water content. Based on the similarity theory, the geological test model of the failure mechanism of Shennu Creek bank slope of the three Gorges Reservoir is established based on the Shennexi Qingshi landslide, and the test conditions of the fluctuation of reservoir water level are worked out, and the model tests are carried out. The pore water pressure data at different elevation of bank slope and the fracture situation of slope body are obtained, and the failure phenomenon of slope body in the whole test process is analyzed, and it is concluded that the change of pore water pressure and the change of groundwater level are the leading inducements affecting the failure of slope body. According to the saturated-unsaturated theory, combined with the experimental model, Midas/GTS numerical simulation software is used to simulate the seepage field change of the slope body to verify the experimental data, and to simulate the Shennexi Qingshi landslide at the same time, The evolution trend of seepage field, displacement field and shear strain increment diagram of bank slope during reservoir operation is obtained: the pore water pressure of bank slope is rising in the stage of rising water level, the displacement of slope foot is first, the stage of water level decreasing, The pore water pressure on the bank slope decreases, and the displacement near the slip surface increases gradually until it is through. 4) the stability coefficient obtained by using Midas/GTS strength reduction method is basically consistent with the stability coefficient calculated by the ground disaster code. Through numerical simulation and stability calculation, it is found that the Qingshi bank slope of Shennexi is in the period of water level storage. Slope stability increased slightly and then decreased. According to the characteristics of geomorphological evolution and the deformation data provided by geological prospecting data, from the softening stage of the slope foot of Qingshi landslide in Shennexi, the upper peristaltic stage of the lower collapse and the pull crack stage at the back of the bank slope, Based on the geological structure of Qingshi landslide in Shennexi, the section below 145m water level is assumed to be elastic zone from 145m to 175m, which is based on catastrophe theory and energy principle. The sudden failure mechanism of this kind of slope secondary landslide is revealed by constructing the mechanical model of the slope failure cusp mutation.
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV697.3;P642.22

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