| 兰州地区白垩系红层泥岩的古风化壳特征研究 |
| Alternative Title | Characteristics of Ancient Wreathering Crust of the Cretaceous Redbed Mudstone in Lanzhou Area
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| 周建基 |
| Thesis Advisor | 梁收运
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| 2015-05-24
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | 红层泥岩
古风化壳
风化程度分带
崩解性
黄土滑坡
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| Abstract | 红层与黄土在中国西部地区广泛分布。黄土下伏的古风化红层基岩往往构成黄土滑坡的底界，是黄土滑坡形成的控制性边界条件。因此，认清泥岩的风化特点和工程属性，对区内滑坡的研究和防治都具有重要意义。本文以兰州及其周边地区白垩系古风化红层泥岩为对象，根据试验结果对卵石层下1m范围内的红层泥岩进行了风化带划分，综合研究了古风化泥岩的崩解性和水岩相互作用，讨论了古风化泥岩对黄土滑坡的控制作用。主要结论如下：
⑴ 硬度试验、回弹试验和磁化率试验结果均显示出相同的规律，即在剖面表层其值较小，随着深度的增加其值增大。
⑵ 对9个岩石剖面进行磁化率试验，发现各剖面均呈现出表层磁化率较大，随着深度的增加磁化率值有所减小的趋势。表层磁化率升高的原因主要为风化作用和成壤作用。
⑶ 崩解试验获取的岩石崩解性变化特征为：卵石层以下0-30cm的岩石崩解性很强，崩解度几乎接近100%；30-50cm的岩石崩解性较强；50-100cm崩解性较弱，其中90-100cm崩解性最弱，崩解度还不到50%。
⑷ 对试验结果进行综合分析得到黄土层底部白垩系红层泥岩古风化壳表面强风化层深度较大，达到卵石层下30-50cm范围，相对来说泥质砂岩剖面强风化层深度较小，处于卵石层下20-30cm的范围内。 |
| Other Abstract | Red bed and loess are widely distributed in western China.The ancient weathered red bedrock under the loess frequently form the bottom boundary of the loess landslide,and it is the control boundary condition.Therefore,knowing the weathering characteristics and engineering properties of weathered mudstone has important significance for the prevention and treatment of loess landslide in the study area.In this paper,we take cretaceous red weathered mudstone in Lanzhou city and the surrounding areas as research objects,processing weathering degree classification and zoning of red bed mudstone within the scope of 1 m under pebble bed,the interaction for collapsing of ancient weathered mudstone and water-rock interaction has been analyzed,the control function of the ancient weathered mudstone to loess landslides is discussed. Main conclusions are as follows:
(1)The results of hardness test,the springback test and susceptibility test showed the same rule.Namely its value in the surface is smaller,with the increase of depth the value is increases.
(2)Magnetic susceptibility test of the nine rock profiles showed that each profile has same tendency which is the magnetic susceptibility is larger on the surface and decreases with the increase of depth.The cause of the increased surface susceptibility is mainly weathering and pedogenesis.
(3)Disintegration test showed that rock disintegration is very strong at 0-30cm below pebble bed and the disintegration degree is close to 100%,rock disintegration is strong at 30-50cm and weaker at 50-100cm,also the weakest at 90-100cm,of which the disintegration degree is less than 50%.
(4)Experimental results show that the depth of strong weathered layer at the surface of cretaceous ancient weathered red mudstone is rather larger which ranges 30-50cm under pebble bed,relatively the depth of strong weathered layer of argillaceous sandstone profile is smaller which ranges 20-30cm under pebble bed. |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/226159
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| Collection | 土木工程与力学学院
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Recommended Citation
GB/T 7714 |
周建基. 兰州地区白垩系红层泥岩的古风化壳特征研究[D]. 兰州. 兰州大学,2015.
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