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干湿交替对元谋干热河谷冲沟发育区不同层位土体抗侵蚀性能的影响
Alternative TitleInfluence of wet and dry alternation on soil antierodibility in different layers of gully developmental zone in Yuanmou Dry Hot Valley Region
Language中文
郑学用
Thesis Advisor熊东红
2015
Degree Grantor中国科学院研究大学
Place of Conferral北京
Degree Name硕士
Degree Discipline环境工程
Keyword干湿交替 土体抗冲性 土体崩解性 抗侵蚀能力 元谋干热河谷
Abstract干热河谷独特的岩土条件和干湿季分明的气候是元谋冲沟发育的重要基础。本研究通过对元谋干热河谷冲沟发育区岩土特征及其剖面状况进行全面考察,通过模拟野外原位土体自然干湿交替作用,采用室内模拟土体冲刷和崩解实验,对冲沟发育区各层位在不同干湿交替处理次数下土体的抗侵蚀能力进行了较深入研究,并对各层位土体抗侵蚀能力进行了综合评价。主要研究结论如下: (1)干湿交替对元谋干热河谷冲沟发育区各层位土体崩解性均有不同程度的增强作用,且其对土体崩解性的影响方式主要体现在增大土体崩解指数和提高土体崩解模数两个方面。不同干湿交替处理次数下,土体崩解模数随干湿交替处理次数的增加而增大,其变化趋势大致符合指数函数:y=A_0×e^((-x/t))+B_0其中,常数A_0 〖、B〗_0 、以及t值的大小因试验土样土质的不同及其所处状态的不同而改变。 (2)干湿交替对元谋干热河谷冲沟发育区不同层位土体抗冲性均有一定弱化作用,且不同干湿交替处理次数下,土体累积冲刷量随干湿交替处理次数的增加而增大,其变化趋势同样符合指数函数:y=A_0×e^((-x/t))+B_0。此外,对于不同土质土体,干湿交替使其抗冲性弱化的原理有一定差异。对于非膨胀土,干湿交替处理对其抗冲性的弱化作用主要表现为对土体结构的破坏。干湿交替处理次数越多,其破坏程度越彻底,受干湿交替处理影响的土体深度也越深。对于膨胀土,干湿交替处理对其抗冲性的弱化作用不仅表现在对土体结构的破坏上,还可通过改变水流侵蚀模式来增大产沙量。 (3)在相同干湿交替处理次数条件下,元谋干热河谷冲沟发育区各层位土体抗侵蚀能力从上到下依次为第Ⅰ层>第Ⅱ层>第Ⅲ层;第Ⅳ层>第Ⅴ层≥第Ⅵ层;其中第Ⅳ层土体抗侵蚀能力与第Ⅰ层接近且略大于第Ⅰ层。 (4)干湿交替对元谋干热河谷冲沟发育区各层位土体抗侵蚀能力因土质、土体所处状态以及所经历的干湿交替处理次数的不同而有所差异。在一定范围内,这种差异影响甚至能逆转不同层位间土体抗侵蚀能力的大小顺序。
Other AbstractSpecial geological conditions and distinct wet and dry season are important basis for the development of gullies in Yuanmou Dry-hot Valley Region. In this study, the geological characteristics and soil profile status in gully developmental zone were studied comprehensively. Alternative wet and dry processing was performed in an on-site soil profiles. Moreover, a disintegration test and scouring tests for alternating wet and dry treated soil from different layers were conducted in laboratory. Finally, a comprehensive evaluation of soil anti-erodibility was conducted. Main results were summarized as follows: (1)The disintegrations of soil from different layers of gully developmental zone in Yuanmou Dry-hot Valley were stringed in different degrees by alternating wet and dry processing. And it affected the soil disintegrations in two ways: Increasing the cumulative modulus of soil disintegration and improving soil disintegration ability. In addition, under different alternating wet and dry processing times, the soil disintegration increased with the increasing of alternating wet and dry processing times. Which trends broadly in line with the exponential function: y=A_0×e^((-x/t))+B_0.In which, the constantA_0, B_0 and t were experimentwith different values because of the differences in soil and the soil in which status of respect. (2)The impact resistances of soil from different layers of gully developmental zone in Yuanmou Dry Hot Valley were weakened in different degrees by alternating wet and dry processing. And under different alternating wet and dry processing times, the cumulative erosion amount of soil increased with the increasing of alternating wet and dry processing times. Which trends broadly in line with the exponential function:y=A_0×e^((-x/t))+B_0. In addition, the weakening principle of the impact soil anti-scourability by alternating wet and dry was differed due to different soil. For non-expansive soil, the impact soil anti-scourabilitywas weakened by the alternating wet and dry processing mainly for the destruction of soil structure. The more the alternating wet and dry processing handed, the more thorough the soil structure damaged, the deeper the soil was treated. For expansive soil, alternating wet and dry processing comply its role of weakeningon the impact resistance of soil not only in the destruction of soil structure, but also by changing the erosion mode of water flow to increase the sediment yield. (3)Under the same conditions of alternating wet and dry processing times. The soil anti-scourability for different layers of gully developmental zone in Yuanmou Dry-hot Valley was sorted as: LayerⅠ>LayerⅡ>LayerⅢ,and LayerⅣ>LayerⅤ>LayerⅥ. As a result the erosion resistance of LayerⅣ is slightly stronger than that of LayerⅠ. (4)The soil anti-scourability from different layers of gully developmental zone in Yuanmou Dry-hot Valley was different from each other due to the difference of the properties of the soil, the state where the soil was in as well as the times of alternating wet and dry processing was conducted. In addition, within a certain range, the different which caused by wet and dry alternation can even reverse the order of erosion resistance of different layers.
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/14144
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
郑学用. 干湿交替对元谋干热河谷冲沟发育区不同层位土体抗侵蚀性能的影响[D]. 北京. 中国科学院研究大学,2015.
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