三峡水库运行期消落带强风化泥岩崩解特性研究

发布时间：2018-01-30 10:09

本文关键词： 强风化泥岩湿干交替岸坡应力崩解特性　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：水库运行期岸坡消落带内泥岩在周期性“湿干”交替作用下易发生崩解,给泥岩岸坡的稳定性带来不利的影响,甚至引起岸坡的失稳。为了研究消落带强风化泥岩的崩解特性,课题组研发了一套可以模拟水库运行期岸坡消落带岩石所处的岸坡应力和周期性“湿干”交替共同作用环境的软岩崩解试验装置(SGRYBJY-2016),通过开展泥岩在“湿干”交替与岸坡应力共同作用下的崩解试验、物质组分变化测试、宏细观结构测试等,获得巴东组强风化紫红色泥岩的崩解规律,揭示水库运行期消落带强风化泥岩崩解机理。具体的研究内容和研究成果概述如下:首先,选取巴东组强风化紫红色泥岩为代表,对水库运行期岸坡消落带“湿干”交替作用环境特征与岸坡应力作用环境特征进行分析,通过水库运行期岸坡消落带环境模拟试验,获得当不考虑岸坡应力(即岸坡表面三向应力为0MPa)时,“湿干”交替作用下泥岩湿化时间和干燥时间分别为4天和1天,获得考虑岸坡应力(即岸坡表面处于两向应力状态)时,“湿干”交替作用下泥岩湿化时间和干燥时间分别为3天和1天;然后,进行泥岩在“湿干”交替作用与岸坡应力共同作用下的崩解试验,崩解试验的每个周期结束后,对母岩及崩解物进行颗分试验,从母岩上取部分碎片进行X射线衍射(XRD)、能量色散谱(EDS)、扫描电镜(SEM)和吸水性测试,取泥岩试样“湿化”过程的浸泡液进行化学成分测试,获得泥岩物质组分、粒径分布和宏细观结构随水库运行期“湿干”交替作用次数的变化规律;接着,根据吸水率和颗分试验结果,建立泥岩吸水率和崩解系数随水库运行期“湿干”交替作用次数变化的数理模型。模型表明,当岸坡表面三向应力均为0MPa时,泥岩吸水率随“湿干”交替作用次数的变化符合对数函数,崩解系数符合指数函数变化;当岸坡表面两向应力分别为0.5MPa和1.0MPa时,泥岩吸水率和崩解系数变化规律均符合指数函数;最后,综合分析泥岩在“湿干”交替作用与岸坡应力共同作用下物质组分、粒径分布和宏细观结构随“湿干”交替作用次数的变规律,揭示三峡库区消落带强风化泥岩在水库运行期的崩解机制。
[Abstract]:In the reservoir running period, the mudstone is liable to collapse under the cyclic "wet dry" alternating action, which has a negative effect on the stability of mudstone bank slope. In order to study the disintegration characteristics of strongly weathered mudstone in the falling zone. A soft rock disintegration test device SGRYBJY-2016 has been developed, which can simulate the interaction environment of slope stress and periodic "wet dry" interaction between the rock in the slope collapse zone during reservoir operation period. . Through the disintegration test of mudstone under the action of "wet dry" alternately and slope stress, material component change test, macroscopical structure test and so on, the disintegration law of Badong formation strongly weathered purple mudstone is obtained. Reveal the collapse mechanism of strongly weathered mudstone in reservoir operation period. The specific research contents and research results are summarized as follows: firstly, the strongly weathered purple mudstone of Badong formation is selected as the representative. The environmental characteristics of "wet dry" alternating action and stress of bank slope in reservoir operation period are analyzed, and the environmental simulation test of bank slope drop zone during reservoir operation period is carried out. When the slope stress is not taken into account (that is, the triaxial stress of the slope surface is 0 MPa), the wetting time and drying time of the mudstone under the alternating action of "wet dry" are 4 days and 1 day, respectively. The wetting time and drying time of mudstone under the alternating action of "wet dry" are 3 days and 1 day, respectively, when the slope stress is considered (that is, the slope surface is in the state of bidirectional stress). Then, the disintegration test of mudstone under the action of "wet dry" alternating action and slope stress is carried out. After each cycle of disintegration test, the parent rock and disintegrating material are tested. Some fragments were taken from the parent rock for X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and water absorption test. The chemical composition of the soaking solution in the process of "humidification" of mudstone samples was tested, and the variation law of mudstone material composition, particle size distribution and macrostructure with the alternating action times of "wet drying" during reservoir operation was obtained. Then, according to the results of water absorption and particle test, a mathematical model of the variation of mudstone water absorption rate and disintegration coefficient with the "wet dry" alternating action times during the reservoir operation period is established. The model shows that. When the surface stress of the slope is 0 MPA, the variation of mudstone water absorption rate with the alternating action times of "wet dry" accords with the logarithmic function, and the disintegration coefficient is in accordance with the exponential function. When the two-direction stress on the slope surface is 0.5 MPA and 1.0 MPA, the variation of mudstone water absorption rate and disintegration coefficient all accord with the exponential function. Finally, the variation law of material composition, particle size distribution and macrostructure of mudstone under the interaction of "wet dry" interaction and slope stress is analyzed synthetically with the "wet dry" alternating action times. The collapse mechanism of strongly weathered mudstone in the three Gorges reservoir area is revealed.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV697.23

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