本文關鍵詞： 飽和-非飽和 降雨入滲 水位驟降 基質吸力 邊坡穩(wěn)定性 條分法　出處：《長沙理工大學》2014年碩士論文　論文類型：學位論文

【摘要】：株洲楓溪港滑坡是楓溪河岸邊坡受到雨水侵蝕、河流沖刷以及洪水位下降等因素的影響而形成的崩塌體滑坡。該崩塌體滑坡屬于次生堆積體,物質成分以土質和破碎巖體為主,結構松軟破碎,粒間結合力差,透水性強,力學性質易受水文因素的影響。長時間的降雨入滲和洪水位的周期性波動,對坡體內滲流場的影響很大,威脅著滑坡的整體穩(wěn)定性。研究降雨入滲和水位驟降條件下崩塌體滑坡的穩(wěn)定性具有重要的意義。本文以楓溪港滑坡為例,基于飽和-非飽和滲流理論研究了降雨入滲和水位驟降對崩塌體滑坡滲流場的影響,得到了坡體內孔隙水壓力的變化規(guī)律,在此基礎上結合非飽和土抗剪強度理論和極限平衡條分法研究了滑坡的穩(wěn)定性。本文主要取得了以下研究成果：(1)降雨強度越大,單位時間內滑坡體的雨水入滲量越多,滑坡體內的孔隙水壓力變化越大,基質吸力降低幅度越大,對滑坡穩(wěn)定性越不利。降雨第3天,降雨強度分別為0.0003m/h、0.0015m/h、0.006m/h時,滑坡安全系數(shù)分別降低了5%、17.4%、20%。當降雨強度大于滑坡體的滲透系數(shù)時,楓溪港滑坡在降雨歷時3天內會發(fā)生失穩(wěn)破壞。(2)降雨歷時越長,滑坡體內孔隙水壓力的變化越大,水位線上升越高,對滑坡穩(wěn)定性越不利。降雨強度為0.0015m/h時,降雨歷時分別為2天、3天、4天時,滑坡的安全系數(shù)由1.16分別降低至1.022、0.958、0.917,降低幅度分別為11.9%、17.4%、21%。降雨強度為0.0015m/h和0.006m/h時,分別在降雨第54小時和第42小時發(fā)生滑坡災害。(3)水位驟降能引起滑坡體內形成滯后的孔壓差,水位下降速度越快,坡體內孔隙水壓力消散越慢,坡體內指向坡外的滲透力越大,對滑坡的穩(wěn)定性越不利。同一高度水位分別以速度0.1m/d、0.4m/d和2m/d下降到同一穩(wěn)定水位高度(7m)時,滑坡安全系數(shù)降低幅度分別為24%、31%和35%。當水位下降速度達到0.4m/d,楓溪港滑坡就有發(fā)生失穩(wěn)破壞的隱患。(4)初始水位高度越高,水位下降至同一穩(wěn)定水位所需時間越長,坡體內積累的孔壓差越大,形成的滲透力也越大,對滑坡的穩(wěn)定性也越不利。當坡外初始水位高度分別為20m、15m、lOm的河水位以相同速度下降到同一穩(wěn)定水位(5m)后,坡體內的浸潤線高度分別降至16m、14m、11m,滑坡安全系數(shù)的降低幅度分別為49%、35%、12%,并且分別在第8天、4天、3天出現(xiàn)滑坡災害。
[Abstract]:Fengxigang landslide in Zhuzhou is a landslide formed by the influence of Rain Water erosion, river scour and water level decline. The landslide belongs to the secondary accumulation body. The main material composition is soil and rock mass, the structure is soft and broken, the intergranular binding force is poor, the permeability is strong, the mechanical property is easily affected by hydrological factors, the long-term rainfall infiltration and the periodic fluctuation of flood water level. It is of great significance to study the stability of landslide under the condition of rainfall infiltration and sudden drop of water level. This paper takes Fengxigang landslide as an example. Based on saturated-unsaturated seepage theory, the influence of rainfall infiltration and water level drop on seepage field of landslide is studied, and the variation law of pore water pressure in slope is obtained. On this basis, the stability of the landslide is studied by combining the shear strength theory of unsaturated soil and the ultimate equilibrium strip method. The following research results are obtained in this paper: 1) the rainfall intensity is greater. The more Rain Water infiltration amount of landslide body per unit time, the greater the pore water pressure in landslide, the larger the decrease of matrix suction, the more unfavorable to landslide stability. The third day of rainfall. When the rainfall intensity was 0.0003 m / h, 0.0015 m / h and 0.006 m / h, the safety factor of the landslide was reduced by 5% or 17.4% respectively. 20. When the rainfall intensity is greater than the permeability coefficient of the landslide, the longer the rainfall duration is, the more the pore water pressure in the landslide will change. When the rainfall intensity is 0.0015 m / h, the rainfall duration is 2 days, 3 days and 4 days, respectively. The safety factor of the landslide was reduced from 1.16 to 1.022 ~ 0.958 ~ 0.917, respectively, and the decrease range was 11.9% or 17.4% respectively. 21. when the rainfall intensity is 0.0015mrh and 0.006mrh. Landslide disaster occurred in the 54th hour and the 42nd hour of rainfall respectively) the sudden drop of water level can cause the formation of lag pore pressure difference in the landslide. The faster the water level drops, the slower the pore water pressure dissipates. The greater the permeability of the slope towards the outside of the slope, the more unfavorable to the stability of the landslide. The water level at the same height is at a velocity of 0.1 m / d respectively. When 0.4m / d and 2m/ d fall to the same stable water level (7m), the landslide safety factor decreases by 24.1% and 35m / d, respectively, when the water level drops at a rate of 0.4m / d. The higher the initial water level height is, the longer it takes for the water level to fall to the same stable water level, the larger the pore pressure difference accumulated in the slope, the greater the permeability. The more unfavorable to the stability of the landslide, when the initial water level outside the slope is 20m ~ 15mO _ m, respectively, the level of the river drops to the same stable water level (5m) at the same speed. The depth of the infiltration line in the slope was reduced to 16 m ~ 14 m ~ (-1) and the safety factor of the landslide was decreased by 49 ~ 35 ~ (12) and 4 days respectively on the 8th day. Landslide disaster occurred in 3 days.
【學位授予單位】：長沙理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：P642.22;TU43

【參考文獻】

相關期刊論文 前2條

1 時衛(wèi)民,鄭穎人;庫水位下降情況下滑坡的穩(wěn)定性分析[J];水利學報;2004年03期

2 戚國慶,黃潤秋,速寶玉,胡云進,詹美禮;巖質邊坡降雨入滲過程的數(shù)值模擬[J];巖石力學與工程學報;2003年04期

，

本文編號：1465185