崩岗区土侵蚀因素及其边坡稳定性研究
发布时间：2019-01-25 21:58
【摘要】：崩岗是我国南方红壤丘陵区的一种严重的水土流失形式。崩岗侵蚀不仅会产生水土流失还容易导致山体滑坡等危害。而随着经济的飞速发展,人们对生活环境的要求提高,并且我国对环境保护日益重视,因此研究崩岗侵蚀对我国以及江西省治理水土流失具有重要的实际意义和需求。水土流失治理研究是一个很大的课题,涉及的学科繁多,本文主要工作是对崩岗区的土壤进行全面的基本特性研究和崩岗侵蚀因素研究,并分析崩岗侵蚀力的组成,再将这些研究作为基础,通过数值模拟分析崩岗区边坡的稳定性。土壤侵蚀研究从理论上可认为是土壤的抗剪强度的研究,通过查阅文献可以发现土壤侵蚀的过程也是抗剪强度变化的过程,所以本文主要是围绕崩岗土的抗剪强度来对崩岗侵蚀进行研究。主要研究工作和结论如下:(1)开展了颗粒密度、颗粒分析、界限含水率、击实渗透、直剪等常规土工试验,系统地测定了崩岗区土的基本物理特性,并对试验结果进行详细的分析、总结,特别是得出采集的土样为粉质粘土;同时对崩岗区的土样进行静三轴试验,准确的得出扰动土样的抗剪强度指标黏聚力c值和内摩擦角υ值,并用于第五章节的数值模拟分析中;(2)对崩岗侵蚀因素进行详细的直接剪切试验研究,这些因素主要有含水率、干密度、石灰掺量、掺入石灰土样的养护时间以及干湿循环。通过试验数据结果分析得出含水率对土样的抗剪强度影响很明显,干密度的降低、干湿循环次数的增加都能降低土样的抗剪强度,而掺入石灰能提高土样的抗剪强度,并且石灰掺量和土样的养护时间与土样的抗剪强度正相关;(3)分析了崩岗的成因机理、岩石的成分特性以及水对土的作用,在已有的理论推导基础上进一步得出崩岗侵蚀中的雨滴侵蚀应力的表达式和崩岗侵蚀区坡面流侵蚀力的表达式,通过理论值和试验结果的对比分析得出雨滴侵蚀影响不容忽视;(4)由于在江西赣州于都县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。本文通过崩岗区的边坡进行数值模拟分析降雨条件下边坡的稳定性来论证削坡治理的效果,边坡的坡度与稳定性系数的关系,以便用于指导实施实际的削坡治理工程;(5)本文还通过直剪试验和数值模拟论证添加石灰能否改善土的性质和增大边坡的稳定性以便达到治理和防治崩岗侵蚀。得出石灰能够增强土的抗剪强度,随着石灰的掺入后经过一段时间的养护,能使石灰土提高黏聚力和内摩擦角,最终通过数值模拟结论得出在边坡表面铺一层石灰土能提高边坡的稳定性系数。
[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.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43
本文编号：2415232
[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.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43
【参考文献】
相关期刊论文 前4条
1 廖安中;崩岗及其防治[J];广东水电科技;1986年01期
2 张萍;查轩;;崩岗侵蚀研究进展[J];水土保持研究;2007年01期
3 史德明;我国热带、亚热带地区崩岗侵蚀的剖析[J];水土保持通报;1984年03期
4 丘世钧;红土坡地崩岗侵蚀过程与机理[J];水土保持通报;1994年06期
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