| 川藏交通廊道黏土化蚀变岩发育特征及其对大型滑坡的促滑作用 |
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| 引用本文： | 张永双,李金秋,任三绍,吴瑞安,毕俊擘.川藏交通廊道黏土化蚀变岩发育特征及其对大型滑坡的促滑作用[J].地球科学,2022,47(6):1945-1956. |
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| 作者姓名： | 张永双 李金秋 任三绍 吴瑞安 毕俊擘 |
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| 作者单位： | 1.中国地质科学院水文地质环境地质研究所, 河北石家庄 050061 |
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| 基金项目： | 国家自然科学基金项目(Nos.41941017,41731287)； |
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| 摘 要： | 黏土化蚀变岩是在岩浆期后热液作用或后期水热作用下形成的具有不良工程地质性质的特殊地质体.在野外调查、黏土矿物测试和物理力学试验分析的基础上，阐述了川藏交通廊道黏土化蚀变岩的形成条件、区域分布特征、地质特征及蚀变程度的判据，以白格滑坡为例揭示了黏土化蚀变岩对大型滑坡的促滑作用.结果表明，黏土化蚀变岩的区域分布受活动断裂、热液作用和地层岩性控制，常沿侵入岩脉、断裂带、岩浆岩节理密集带、侵入岩体与其他岩层的接触带等部位发育，其蚀变程度按蚀变系数可划分为微蚀变、弱蚀变、中等蚀变和强蚀变4个等级，在干湿交替和松弛条件下极易发生崩解、软化，中等-强蚀变的岩体抗剪强度低.黏土化蚀变岩对滑坡的促滑作用主要体现在强度弱化效应、岩体结构劣化效应及失稳滞后效应3个方面，是促进构造混杂岩带深切河谷斜坡失稳、形成大型滑坡不可忽视的重要因素.
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| 关 键 词： | 构造混杂岩带 黏土化蚀变岩 工程地质特性 促滑作用 白格滑坡 |
| 收稿时间： | 2021-09-15 |
Development Characteristics of Clayey Altered Rocks in the Sichuan-Tibet Traffic Corridor and Their Promotion to Large-Scale Landslides |
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| Abstract: | Clayey altered rock is a special geological body with poor engineering geological properties formed under hydrothermal action or hydrothermal action after the magmatic period. Based on field geological survey, clay mineral identification, and physical mechanics test analysis, the formation conditions, regional distribution characteristics, geological characteristics and the criterion of alteration degree of clayey altered rocks in the Sichuan-Tibet traffic corridor are described. Taking Baige landslide as an example, the sliding promotion of clayey altered rock on large-scale landslides are discussed. The results show that the regional distribution of clayey altered rocks is controlled by active faults, hydrothermal action and lithology. The clayey altered rocks often develop along intrusive dikes, fault zones, concentrated joint zones of magmatic rocks, and contact zones between intrusive rock mass and other rock formation. According to the alteration coefficient, the degree of alteration can be divided into four grades: very low alteration, low alteration, medium alteration and high alteration. In alternating wet and dry conditions and relaxation conditions, the altered rock is easy to disintegrate and soften. The medium-high altered rock mass usually has low shearing strength. The promoting effect of clayey altered rock on landslide is mainly reflected in three aspects: strength weakening effect, rock mass structure deterioration effect and instability hysteresis effect, which is an important factor in promoting the instability of slopes and large-scale landslides in deep-cut valley slopes in tectonic melange belts. |
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