【摘要】：黃土在我國廣泛分布，黃土滑坡問題嚴(yán)重。近年來，對滑坡災(zāi)害的研究和治理日益引起人們的重視，，但由于黃土特殊的結(jié)構(gòu)性和力學(xué)特性，導(dǎo)致對滑坡內(nèi)在機(jī)理的研究具有很大的難度。為了對黃土滑坡內(nèi)在規(guī)律有進(jìn)一步的了解，本文以楊凌黃土為研究對象，進(jìn)行了黃土邊坡室內(nèi)模型試驗(yàn)，探索邊坡在人工降雨作用下的漸進(jìn)破壞規(guī)律。同時(shí)利用FLAC3D分析了邊坡在不同含水率和雨水入滲不同深度下，邊坡變形發(fā)展、剪切滑移和失穩(wěn)漸進(jìn)破壞過程，最后分析了邊坡在坡頂加載條件下的漸進(jìn)破壞過程，本文取得的主要結(jié)論如下： （1）在降雨初期，水分平均入滲率為86%，之后隨著地表徑流增加，入滲速率降低，最后維持在40%左右。在整個(gè)過程中，土體的滲透能力逐漸降低，邊坡某些區(qū)域土體達(dá)到飽和狀態(tài)。 （2）在降雨作用下，邊坡開始會(huì)產(chǎn)生坡面沖蝕和水土流失，并出現(xiàn)許多張拉裂縫和沖蝕溝，當(dāng)這些裂縫在坡體內(nèi)部相互貫通時(shí)，潛在滑動(dòng)面形成，隨后雨水進(jìn)一步入滲就會(huì)產(chǎn)生較大規(guī)模崩滑，滑動(dòng)區(qū)為坡面以下0~1.6m之間。 （3）邊坡內(nèi)部只有含水率變化較大的區(qū)域，土體運(yùn)動(dòng)才最劇烈，這說明水分對邊坡失穩(wěn)有很大的影響。含水率增加致使土體有效應(yīng)力降低以及導(dǎo)致水分向坡外的滲透力增加，從而使邊坡不穩(wěn)定。 (4)在降雨入滲致使土體含水率變化條件下，隨著邊坡均布含水率的增加，坡腳的局部開始出現(xiàn)應(yīng)變局部化現(xiàn)象；當(dāng)邊坡含水率達(dá)到一定值時(shí)，剪切帶從坡腳開始出現(xiàn)，隨著含水率繼續(xù)增加，剪切帶逐步發(fā)展，當(dāng)邊坡濕度上升到一定程度時(shí)后，剪切帶貫通，邊坡開始滑動(dòng)。 （5）在雨水不同入滲深度條件下，隨著入滲深度的增加，邊坡經(jīng)歷3個(gè)階段。第一階段，邊坡表層土體迅速失穩(wěn)，但邊坡整體穩(wěn)定；第二階段，雨水進(jìn)一步入滲，致使坡體內(nèi)部開始出現(xiàn)塑性區(qū)和表面裂縫，坡體穩(wěn)定性開始大幅下降；第三階段，雨水入滲到坡體內(nèi)部，致使裂縫和塑性區(qū)貫通，剪切帶從坡腳到坡頂貫通，邊坡失穩(wěn)破壞。 （6）邊坡破壞時(shí)坡體明顯的分為滑動(dòng)體和穩(wěn)定體兩部分，它們之間具有明顯的位移梯度差值。同時(shí)，滑動(dòng)體上各點(diǎn)的運(yùn)動(dòng)既有土體本身的變形運(yùn)動(dòng)也有滑動(dòng)體的滑動(dòng)，并且土體本身的變形運(yùn)動(dòng)遠(yuǎn)大于滑動(dòng)體整體的滑動(dòng)。
[Abstract]:Loess is widely distributed in China, and the problem of loess landslide is serious. In recent years, people pay more and more attention to the study and management of landslide disasters, but because of the special structural and mechanical characteristics of loess, it is very difficult to study the inherent mechanism of landslide. In order to further understand the inherent law of loess landslide, this paper takes Yang Ling loess as the research object, carries on the loess slope indoor model test, explores the slope progressive failure law under the action of artificial rainfall. At the same time, FLAC3D is used to analyze the process of slope deformation development, shear slip and instability progressive failure under different water content and Rain Water infiltration depth. Finally, the progressive failure process of slope under the condition of top loading is analyzed. The main conclusions obtained in this paper are as follows: (1) at the beginning of rainfall, the average water infiltration rate is 86%, then with the increase of surface runoff, the infiltration rate decreases, and the infiltration rate is maintained at about 40%. In the whole process, the permeability of soil decreases gradually, and the soil reaches saturation state in some areas of slope. (2) under the action of rainfall, the slope begins to produce erosion and soil erosion on the slope, and many tensile cracks and erosion ditches appear. When these cracks are connected with each other in the body of the slope, the potential sliding surface is formed. Further infiltration by Rain Water will result in a large scale collapse and slip, and the sliding area is between 0 ~ 1.6 m below the slope surface. (3) in the slope, the movement of soil is the strongest only in the area where the moisture content changes greatly, which indicates that the moisture has a great influence on the instability of the slope. The increase of moisture content decreases the effective stress of soil and increases the permeability of the soil outside the slope, which makes the slope unstable. (4) under the condition that the soil moisture content changes due to rainfall infiltration, the strain localization begins to occur at the foot of the slope with the increase of the average moisture content of the slope; When the water content of the slope reaches a certain value, the shear zone begins to appear at the foot of the slope. With the increase of the moisture content, the shear zone develops gradually. When the humidity of the slope reaches a certain degree, the shear zone passes through and the slope begins to slide. (5) under the condition of different infiltration depth of Rain Water, the slope goes through three stages with the increase of infiltration depth. In the first stage, the surface soil of the slope is rapidly unstable, but the slope is stable as a whole, in the second stage, Rain Water further infiltrates, causing the plastic zone and surface cracks in the slope body to begin to appear, and the stability of the slope body begins to decline substantially. In the third stage, Rain Water infiltrates into the body of the slope, which leads to the fracture and plastic zone through, the shear zone from the foot of the slope to the top of the slope, and the slope is unstable and destroyed. (6) during slope failure, the slope body is obviously divided into two parts: sliding body and stable body, and the difference of displacement gradient between them is obvious. At the same time, the movement of each point on the sliding body is not only the deformation motion of the soil itself but also the sliding movement of the sliding body, and the deformation motion of the soil itself is much larger than that of the whole sliding body.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU411

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 馬水山,雷俊榮,張保軍,王志旺;滑坡體水巖作用機(jī)制與變形機(jī)理研究[J];長江科學(xué)院院報(bào);2005年05期

2 鄧清祿,王學(xué)平;黃土坡滑坡的發(fā)育歷史:墜覆-滑坡-改造[J];地球科學(xué);2000年01期

3 陳松;陳國金;徐光黎;;黃土坡滑坡形成與變形的地質(zhì)過程機(jī)制[J];地球科學(xué)(中國地質(zhì)大學(xué)學(xué)報(bào));2008年03期

4 陳永明;石玉成;;中國西北黃土地區(qū)地震滑坡基本特征[J];地震研究;2006年03期

5 張茂省;李同錄;;黃土滑坡誘發(fā)因素及其形成機(jī)理研究[J];工程地質(zhì)學(xué)報(bào);2011年04期

6 黃春林;李永倩;楊志;李成賓;;BOTDR技術(shù)在山體滑坡監(jiān)測中的應(yīng)用研究[J];工程抗震與加固改造;2009年06期

7 譚文輝;周汝弟;;數(shù)值模擬與極限平衡方法在復(fù)雜邊坡優(yōu)化中的應(yīng)用研究[J];金屬礦山;2009年01期

8 許文耀;李德宏;王湘桂;;水-巖耦合作用下邊坡巖體滲流二維數(shù)值模擬[J];金屬礦山;2011年12期

9 王少華;趙宗勇;郭靖;楊金強(qiáng);;基于FLAC~(3D)強(qiáng)度折減法的三種收斂判據(jù)的比較分析[J];現(xiàn)代礦業(yè);2011年02期

10 徐佩華,陳劍平,黃潤秋,嚴(yán)明;錦屏Ⅰ級(jí)水電站解放溝左岸邊坡傾倒變形機(jī)制的3D數(shù)值模擬[J];煤田地質(zhì)與勘探;2004年04期

相關(guān)碩士學(xué)位論文 前1條

1 馬健;粘性土坡破壞機(jī)制及FLAC數(shù)值模擬[D];同濟(jì)大學(xué);2006年

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