【摘要】：崩崗是我國(guó)南方紅壤丘陵區(qū)的一種嚴(yán)重的水土流失形式。崩崗侵蝕不僅會(huì)產(chǎn)生水土流失還容易導(dǎo)致山體滑坡等危害。而隨著經(jīng)濟(jì)的飛速發(fā)展,人們對(duì)生活環(huán)境的要求提高,并且我國(guó)對(duì)環(huán)境保護(hù)日益重視,因此研究崩崗侵蝕對(duì)我國(guó)以及江西省治理水土流失具有重要的實(shí)際意義和需求。水土流失治理研究是一個(gè)很大的課題,涉及的學(xué)科繁多,本文主要工作是對(duì)崩崗區(qū)的土壤進(jìn)行全面的基本特性研究和崩崗侵蝕因素研究,并分析崩崗侵蝕力的組成,再將這些研究作為基礎(chǔ),通過(guò)數(shù)值模擬分析崩崗區(qū)邊坡的穩(wěn)定性。土壤侵蝕研究從理論上可認(rèn)為是土壤的抗剪強(qiáng)度的研究,通過(guò)查閱文獻(xiàn)可以發(fā)現(xiàn)土壤侵蝕的過(guò)程也是抗剪強(qiáng)度變化的過(guò)程,所以本文主要是圍繞崩崗?fù)恋目辜魪?qiáng)度來(lái)對(duì)崩崗侵蝕進(jìn)行研究。主要研究工作和結(jié)論如下:(1)開(kāi)展了顆粒密度、顆粒分析、界限含水率、擊實(shí)滲透、直剪等常規(guī)土工試驗(yàn),系統(tǒng)地測(cè)定了崩崗區(qū)土的基本物理特性,并對(duì)試驗(yàn)結(jié)果進(jìn)行詳細(xì)的分析、總結(jié),特別是得出采集的土樣為粉質(zhì)粘土;同時(shí)對(duì)崩崗區(qū)的土樣進(jìn)行靜三軸試驗(yàn),準(zhǔn)確的得出擾動(dòng)土樣的抗剪強(qiáng)度指標(biāo)黏聚力c值和內(nèi)摩擦角υ值,并用于第五章節(jié)的數(shù)值模擬分析中;(2)對(duì)崩崗侵蝕因素進(jìn)行詳細(xì)的直接剪切試驗(yàn)研究,這些因素主要有含水率、干密度、石灰摻量、摻入石灰土樣的養(yǎng)護(hù)時(shí)間以及干濕循環(huán)。通過(guò)試驗(yàn)數(shù)據(jù)結(jié)果分析得出含水率對(duì)土樣的抗剪強(qiáng)度影響很明顯,干密度的降低、干濕循環(huán)次數(shù)的增加都能降低土樣的抗剪強(qiáng)度,而摻入石灰能提高土樣的抗剪強(qiáng)度,并且石灰摻量和土樣的養(yǎng)護(hù)時(shí)間與土樣的抗剪強(qiáng)度正相關(guān);(3)分析了崩崗的成因機(jī)理、巖石的成分特性以及水對(duì)土的作用,在已有的理論推導(dǎo)基礎(chǔ)上進(jìn)一步得出崩崗侵蝕中的雨滴侵蝕應(yīng)力的表達(dá)式和崩崗侵蝕區(qū)坡面流侵蝕力的表達(dá)式,通過(guò)理論值和試驗(yàn)結(jié)果的對(duì)比分析得出雨滴侵蝕影響不容忽視;(4)由于在江西贛州于都縣在治理水土流失做了大量工作,并且也取得了一定的治理效果。本文通過(guò)崩崗區(qū)的邊坡進(jìn)行數(shù)值模擬分析降雨條件下邊坡的穩(wěn)定性來(lái)論證削坡治理的效果,邊坡的坡度與穩(wěn)定性系數(shù)的關(guān)系,以便用于指導(dǎo)實(shí)施實(shí)際的削坡治理工程;(5)本文還通過(guò)直剪試驗(yàn)和數(shù)值模擬論證添加石灰能否改善土的性質(zhì)和增大邊坡的穩(wěn)定性以便達(dá)到治理和防治崩崗侵蝕。得出石灰能夠增強(qiáng)土的抗剪強(qiáng)度,隨著石灰的摻入后經(jīng)過(guò)一段時(shí)間的養(yǎng)護(hù),能使石灰土提高黏聚力和內(nèi)摩擦角,最終通過(guò)數(shù)值模擬結(jié)論得出在邊坡表面鋪一層石灰土能提高邊坡的穩(wěn)定性系數(shù)。
[Abstract]:Collapse is a serious form of soil erosion in the hilly region of red soil in southern China. Collapse erosion will not only produce soil erosion, but also easily lead to landslides and other hazards. With the rapid development of economy, people's demands on living environment are raised, and our country pays more attention to environmental protection. Therefore, it is of great practical significance and demand to study the erosion of landslide in our country and Jiangxi Province. The study of soil erosion control is a great subject, which involves many subjects. The main work of this paper is to study the basic characteristics of the soil and the factors of erosion in the collapse area, and to analyze the composition of the erosion force. On the basis of these studies, the stability of slope in caving area is analyzed by numerical simulation. The study of soil erosion can be regarded as the study of soil shear strength theoretically, and the process of soil erosion is also the process of shear strength change. Therefore, this paper mainly focuses on the shear strength of rockfall soil to study collapse erosion. The main research work and conclusions are as follows: (1) the basic physical properties of the soil in the caving area have been systematically measured by conventional geotechnical tests such as particle density, particle analysis, limit moisture content, compaction infiltration, direct shear and so on. The test results are analyzed and summarized in detail, especially the silty clay is obtained. At the same time, the static triaxial test was carried out on the soil samples in the caving area, and the cohesive force c value and the internal friction angle value of the disturbed soil samples were accurately obtained, which were used in the numerical simulation analysis of the fifth chapter. (2) the factors of collapse erosion are studied by direct shear test. These factors include moisture content, dry density, lime content, curing time of lime soil sample and dry and wet cycle. Through the analysis of the test data, it is concluded that the moisture content has an obvious effect on the shear strength of the soil sample. The decrease of dry density and the increase of the times of dry and wet cycles can all reduce the shear strength of the soil sample, while the addition of lime can improve the shear strength of the soil sample. The content of lime and the curing time of soil samples are positively correlated with the shear strength of soil samples. (3) the genetic mechanism, the composition characteristics of rock and the effect of water on soil are analyzed. On the basis of existing theoretical derivation, the expression of raindrop erosion stress in collapse erosion and the expression of slope flow erosivity in collapse erosion area are obtained. Through the comparison and analysis of theoretical values and experimental results, it is concluded that the influence of raindrop erosion should not be ignored. (4) a great deal of work has been done to control soil and water loss in Yudu County, Ganzhou, Jiangxi Province, and some effects have been obtained. In this paper, the stability of slope under rainfall condition is analyzed by numerical simulation of slope in collapse area to demonstrate the effect of slope cutting and the relationship between slope gradient and stability coefficient, so as to guide the implementation of actual slope cutting project. (5) through direct shear test and numerical simulation, it is proved that the addition of lime can improve the properties of soil and increase the stability of slope in order to control and prevent collapse erosion. It is concluded that lime can enhance the shear strength of soil. With the addition of lime and curing for a period of time, lime soil can increase cohesion and internal friction angle. Finally, it is concluded by numerical simulation that a layer of lime soil on the slope surface can improve the slope stability coefficient.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TU43

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本文編號(hào)：2415232