| 薄层灰岩浅部岩溶发育特征及分布模型 |
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| 引用本文： | 张宽,唐朝晖,柴波,孙巧,张洁飞.薄层灰岩浅部岩溶发育特征及分布模型[J].水文地质工程地质,2019,0(4):167-174. |
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| 作者姓名： | 张宽 唐朝晖 柴波 孙巧 张洁飞 |
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| 作者单位： | 1.中国地质大学（武汉）工程学院，湖北 武汉430074；2.中国地质大学（武汉）环境学院，湖北 武汉430074； 3.中铁第四勘察设计院集团有限公司，湖北 武汉430074 |
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| 基金项目： | 国家自然科学基金资助项目(41572256；41877253)；中央高校基本科研业务费专项资金资助项目(CUGL160408) |
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| 摘 要： | 碳酸盐岩往往含有较多泥质夹层，多发育浅部岩溶裂隙，影响工程基础稳定性。文章依托广西合山市溯河矿区某道路浅部岩溶调查成果，分析了薄层灰岩岩溶宏观形态和垂直分布特征，按照溶蚀程度将其分为碎屑残留带、表层岩溶带和下部包气带；通过室内溶蚀试验，分析了矿物组成、CO2及水动力条件影响下的溶蚀规律；对比分析了薄层和厚层岩溶发育特征。结果表明:（1）薄层灰岩浅部岩溶发育程度与微地貌有关，通常在山谷和地下水强径流带溶蚀作用更为强烈；（2）薄层灰岩溶蚀优先开始于方解石，在岩石表面形成溶孔、粗糙程度增加，提供了侵蚀性溶液流动通道；（3）薄层灰岩岩溶较厚层灰岩岩溶规模小，分布较为均匀，由地表土体渗入地下岩体的地下水含有较多侵蚀性CO2水溶液，会促进岩溶作用的进行；（4）薄层灰岩浅部岩溶发育分布模型为:发育均匀的微小溶蚀裂隙在溶蚀下渗过程中遇到软弱夹层时会沿水平向扩展并随进一步溶蚀作用被充填，垂向深部发展时溶蚀作用逐步消散。
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| 关 键 词： | 岩溶 薄层灰岩 软弱夹层 溶蚀规律 分布模型 |
| 收稿时间： | 2019-01-06 |
| 修稿时间： | 2019-03-21 |
Development characteristics and distribution model of shallow karst in thin-bed limestones |
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| ZHANG Kuan,TANG Zhaohui,CHAI Bo,SUN Qiao,ZHANG Jiefei.Development characteristics and distribution model of shallow karst in thin-bed limestones[J].Hydrogeology and Engineering Geology,2019,0(4):167-174. |
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| Authors: | ZHANG Kuan TANG Zhaohui CHAI Bo SUN Qiao ZHANG Jiefei |
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| Affiliation: | 1.Faculty of Engineering，China University of Geosciences(Wuhan)，Wuhan，Hubei430074，China；2.School of Environmental Studies，China University of Geosciences(Wuhan), Wuhan，Hubei430074，China；3.China Railway Fourth Survey and Design Institute Group Co. ，Ltd. Wuhan，Hubei430074，China |
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| Abstract: | Thin-layer carbonate rocks often contain more argillaceous interlayers, and more shallow karst fissures were formed, which may affect the stability of engineering foundation. However, there are few studies on the characteristics and occurrence of karst development in thin-layer limestones, which cannot effectively guide the exploration and design of engineering activities. In order to explore the characteristics of shallow karst development in thin limestones, based on the results of shallow karst investigation on a road in the Heihe mining area near the city of Heshan in Guangxi, the macroscopic and vertical distribution characteristics of thin layer limestone karst are analyzed. According to the degree of dissolution, it is divided into the clastic residual zone, surface karst zone and lower aeration zone. The dissolution process under the influence of mineral composition, CO2 and hydrodynamic conditions is analyzed by the indoor dissolution test. The thin-layer and thick-layer karst development characteristics are compared and analyzed. The results show that (1) the degree of karst development in the shallow layer of limestone is related to the micro-geomorphology, which is usually more intense in the valley and strong groundwater runoff zone. (2) The karst erosion of thin limestone begins preferentially with calcite, forming karst holes and increasing roughness on the surface of rock, which provides corrosive solution flow channels. (3) The karst of thin limestones is smaller in scale and more uniform in distribution, and the groundwater infiltrated into underground rock mass by surface soil contains more erosive CO2 aqueous solution, which will promote the development of karstification. (4) The evenly developed micro-cavitation cracks will expand horizontally in the process of dissolution and infiltration, and will be filled with further dissolution. The dissolution will gradually dissipate in the vertical deep development. Understanding the karst development characteristics and distribution model of shallow limestone in shallow rocks is of a guiding value for the difference in the accuracy of engineering survey work and the selection of basic engineering for the same type of karst site in different regions. |
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