| 黑方台红层泥岩的风化作用及其古风化壳特征 |
| Alternative Title | Characteristics of Weathering and Ancient Weathered Crust of the Red Bed Mudstone in Heifangtai Area
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| 贾雪梅 |
| Thesis Advisor | 梁收运
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| 2014-05-25
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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
风化作用
古风化壳
微观结构
地球化学特征
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| Abstract | 针对黄土——红层不整合面下伏基岩的风化问题，以黑方台白垩系红层泥岩及其古风壳为研究对象，通过野外现场调查和硬度测试、系统地样品采集和室内以微观结构为主的多种测试，初步尝试探索了红层泥岩的球状风化过程中和古风化壳剖面上泥岩的粒度成分、微观结构、主量元素以及矿物组成的变化规律，主要结论如下：
(1) 红层泥岩边坡现代风化主要集中于浅表层(3~6cm)，表现为连续、渐进的破坏过程，并以表层球状碎化、剥落为特征，这种风化作用与其本身的物质组成和微观结构密切相关。
(2) 不同测试结果在古风化壳剖面中规律性较为复杂。从上到下：硬度值有增大趋势，30~40cm以下明显较小，约60处取得最大值；微观结构均由相对疏松变得较为致密，孔隙率和孔隙数量均有减小、减少的趋势；主量元素和粘土矿物含量在两个剖面上表现出不同的分布规律。
(3) 古风化壳风化带的垂直划分，两个古风化壳均形成于干旱炎热古气候条件下，且保存不完整。不整合面下约30cm以内为相对强风化带，30~60cm之间为相对弱风化带，而60cm以下风化作用则很微弱，即，约30cm处为相对强弱风化的分界。
(4)古风化壳结构特征的差异，在一定程度上，控制了黄土滑坡剪出口的位置。 |
| Other Abstract | Based on the field investigation, taking two typical ancient weathered crusts of cretaceous red bed mudstone and one modern slope weathering profile as the research objects, we analyzed the change law of particle size, microstructure, major elements and mineral composition, analyzed the spherical weathering mechanism of red bed mudstone and explored the developmental regular pattern of ancient weathered crusts. The results show as follows.
(1) Modern weathering of red bed mudstone slope mainly concentrates on the shallow surface (3~6cm), which is characterized by continuous, gradual destruction process and particles crushing and spalling. The weathering is closely related by material composition and microstructure of red bed mudstone.
(2) Different test results in the ancient weathering crust show different laws. From top to bottom microstructure becomes denser. The count of pores and apparent porosity gradually decrease. The contents of major elements and clay mineral show different laws in two profiles.
(3) The vertical zoning of ancient weathered crust. The two profiles are along to the leaching and eluvial ancient weathered crusts under the condition of dry and hot paleoclimate, but they are not preserved completely. The vertical zoning of ancient weathered crust presents that the layer within about 30cm below the unconformity is the relative strong weathered zone; the layer from 30cm to 60cm is the relative weak weathered zone, while the wreathing of the layer excesses 60 cm is rather weaker. Briefly, the interface of strong and weak weathered zone is located at about 30cm below the unconformity.
(4) The relationship between ancient weathered crust and landslide types. The structure and material characteristics of ancient weathered crust, to some content, control the location of shear outlet of landslides. |
| 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/262010/226369
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| Collection | 土木工程与力学学院
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Recommended Citation
GB/T 7714 |
贾雪梅. 黑方台红层泥岩的风化作用及其古风化壳特征[D]. 兰州. 兰州大学,2014.
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