| 三峡库区消落带巴东组软岩抗剪强度劣化机理 |
| |
| 引用本文： | 简文星,李世金,陶良.三峡库区消落带巴东组软岩抗剪强度劣化机理[J].地质科技通报,2015,34(4):170-175. |
| |
| 作者姓名： | 简文星 李世金 陶良 |
| |
| 作者单位： | 1. 中国地质大学工程学院, 武汉 430074; |
| |
| 基金项目： | 国家自然科学基金项目(41272306) |
| |
| 摘 要： | 三峡水库蓄水后,库区岸坡的消落带岩土体在库水周期性升降的作用下处于一种“干燥-浸湿”的循环状态。这种干湿循环作用将造成岩土体强度的劣化,并且随着劣化效应的增加,引起岸坡失稳,进而引发严重的地质灾害。以三峡库区巴东县巴东组第二段和第四段软岩为研究对象,在详细的野外调研基础之上,通过不同干湿循环次数下的软岩抗剪强度试验,模拟库水升降对软岩的水岩相互作用过程,探讨了巴东组软岩受库水“干燥-浸湿”循环作用下抗剪强度的劣化规律,利用X射线衍射方法对软岩的矿物成分进行分析,探讨消落带软岩的风化崩解机理。研究发现,巴东组第二段和第四段软岩分别在经历第1次和第3到5次干湿循环时,抗剪强度发生严重劣化;第二段软岩抗剪强度的劣化是由于蒙脱石遇水膨胀造成,第四段软岩抗剪强度的劣化是由于岩石中楔裂压力的发展造成。研究结果可以为岸坡稳定性评价提供理论依据。
|
| 关 键 词： | 三峡库区 消落带 干湿循环 巴东组软岩 劣化机理 |
| 收稿时间： | 2015-01-07 |
Deterioration Mechanism of Shear Strength of Badong Formation Soft Rocks in the Hydro-Fluctuation Belt of Three Gorges Reservoir |
| |
| Institution: | 1. Faculty of Engineering, China University of Geosciences, Wuhan 430074, China;2. Three Gorges Research Center for Geohazards of Ministry of Education, China University of Geosciences, Wuhan 430074, China;3. Wuhan Geomatic Institute, Wuhan 430022, China |
| |
| Abstract: | With the periodic impounding and draining of the Three Gorges Project,the rocks and soils in the hydro-fluctuation belt would undergo "wetting and drying" cycles under the influence of reservoir water fluctuation.The mechanical strength of rocks and soils would deteriorate due to the effects of dryingwetting,and it would cause great damage to the bank slope stability,which might further induce a catastrophic geo-hazard.This study was performed to investigate the changes in the mechanical parameters of soft rocks from Badong Formation under the influence of wetting and drying cycles.For this purpose,the shearing test under different wetting and drying cycles was conducted to simulate the process of water-rock interaction on bank slopes during fluctuation of water level with Badong Formation soft rocks,and to explore the deteriorated shear strength of soft rocks under drying-wetting cycles.The mineral compositions of selected samples of soft rocks were measured to investigate the weathering and slaking mechanism of soft rocks in the hydro-fluctuation by X-ray diffraction experiment.The test results show that the greatest deterioration in values of shear strength for T2b2 and T2b4 was observed after 1and 3-5cycles,respectively.The deterioration mechanism was different in T2b2 and T2b4,the shear strength deterioration in T2b2 was due to the expansibility of montmorillonite,and that in T2b4 was due to the development of fracture pressure.Research results may have an important reference for stability analysis of reservoir bank slopes. |
| |
| Keywords: | |
|
| 点击此处可从《地质科技通报》浏览原始摘要信息 |
| 点击此处可从《地质科技通报》下载免费的PDF全文 |
|
