【摘要】：水是黃土滑坡的誘發(fā)因素之一,本文通過(guò)室內(nèi)試驗(yàn)研究了雨水的入滲過(guò)程、邊坡的變形破壞特征以及降雨入滲中的裂隙演變特征。監(jiān)測(cè)并分析降雨過(guò)程中土體含水率、孔隙水壓力以及基質(zhì)吸力的變化過(guò)程,分析裂隙黃土邊坡變形破壞演變規(guī)律。開(kāi)展了黃土邊坡的滴灌試驗(yàn),分為60°和45°邊坡進(jìn)行試驗(yàn),研究了滴灌對(duì)邊坡穩(wěn)定性的影響。進(jìn)行壓力板儀試驗(yàn),獲取了黃土的土-水特征曲線,結(jié)合滲流理論、彈性力學(xué),獲取二維非飽和土的水-力耦合控制方程。用COMSOL Multiphysics有限元軟件對(duì)非飽和土滲流耦合控制方程進(jìn)行計(jì)算,探索黃土邊坡降雨入滲問(wèn)題,對(duì)模型試驗(yàn)與數(shù)值結(jié)果進(jìn)行比較分析。主要得出以下幾點(diǎn)結(jié)論:(1)在降雨過(guò)程中,邊坡變形比較明顯,受裂隙影響,在裂隙周圍不斷的產(chǎn)生拉裂縫,且呈現(xiàn)多級(jí)演化特征。裂隙為坡體的水分運(yùn)移提供優(yōu)先通道�？紫端畨毫ν蛔兺殡S滑坡或局部大變形的產(chǎn)生,坡體內(nèi)孔隙水壓力隨著降雨時(shí)間的增加而增大,坡腳、裂隙和坡肩孔隙水壓力變化最為顯著。(2)在室內(nèi)滴灌試驗(yàn)下,邊坡的破壞類型可歸納為坡腳局部滑塌-坡肩局部滑動(dòng)-整體滑坡,坡腳和坡肩出現(xiàn)多次局部滑塌,孔隙水壓力的突變是滑坡的主要征兆。坡表變形較明顯,邊坡由外向內(nèi)位移逐漸減小。60°邊坡滑動(dòng)啟動(dòng)時(shí)間要比45°邊坡滑動(dòng)啟動(dòng)時(shí)間要早,更易發(fā)生整體滑動(dòng),滑動(dòng)距離遠(yuǎn)。(3)數(shù)值計(jì)算表明隨著降雨時(shí)間增大,水平位移也逐漸變大,但變化速率逐漸變緩,坡面處水平位移較大,其中坡腳水平位移最為集中。近坡表部位總位移較大,坡肩、坡腳部位最為突出,由坡表向坡體內(nèi)部總位移逐漸變小。裂隙為水的運(yùn)移提供了優(yōu)先路徑,裂隙處的孔隙水壓力變化明顯。
[Abstract]:Water is one of the inductive factors of loess landslide. The infiltration process of Rain Water, the deformation and failure characteristics of slope and the evolution characteristics of cracks in rainfall infiltration are studied in this paper. The changes of soil moisture content pore water pressure and matrix suction during rainfall are monitored and analyzed. The deformation and failure evolution of fractured loess slope is analyzed. The experiment of drip irrigation on loess slope was carried out, which was divided into 60 擄and 45 擄slope, and the influence of drip irrigation on slope stability was studied. The soil-water characteristic curve of loess was obtained by means of pressure plate test. Combined with seepage theory and elastic mechanics, the water-force coupling governing equation of two-dimensional unsaturated soil was obtained. The coupling governing equation of unsaturated soil seepage was calculated by COMSOL Multiphysics finite element software, and the rainfall infiltration problem of loess slope was explored. The model test and numerical results were compared and analyzed. The main conclusions are as follows: (1) in the process of rainfall, the slope deformation is obvious, affected by cracks, the tension cracks are constantly produced around the cracks, and the characteristics of multi-level evolution are presented. The fissure provides the preferential passage for the water movement of the slope body. The sudden change of pore water pressure is often accompanied by landslide or local large deformation. The pore water pressure in slope increases with the increase of rainfall time. The pore water pressure of slope foot, fissure and shoulder is the most significant. (2) under the indoor drip irrigation test, the pore water pressure in slope is the most significant. The failure types of slope can be summed up as local sloughing at the foot of the slope, local sliding at the shoulder of the slope and a whole landslide, and several local landslides at the foot of the slope and the shoulder of the slope. The abrupt change of pore water pressure is the main sign of the landslide. The slope surface deformation is obvious, and the slope sliding start time is earlier than that of 45 擄slope sliding starting time. (3) numerical calculation shows that with the increase of rainfall time, the sliding start time of slope is shorter than that of 45 擄slope. (3) numerical calculation shows that the sliding start time increases with rainfall time. The horizontal displacement also became larger, but the change rate gradually slowed down, and the horizontal displacement at the slope was larger, among which the horizontal displacement at the foot of the slope was the most concentrated. The total displacement of the near slope surface is larger, the slope shoulder and the slope foot are the most prominent, and the total displacement from the slope surface to the slope body becomes smaller gradually. The fissure provides a preferential path for water migration, and the pore water pressure changes obviously.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P642.22

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