| 长期静水浸泡对三峡库区滑带土物理-化学-力学性质的影响 |
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| 引用本文： | 张迪,李岚星,胡新丽,牛李飞,王斌,王强.长期静水浸泡对三峡库区滑带土物理-化学-力学性质的影响[J].地质科技通报,2021,40(5):281-289. |
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| 作者姓名： | 张迪 李岚星 胡新丽 牛李飞 王斌 王强 |
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| 基金项目： | 国家自然科学基金重点项目41630643 |
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| 摘 要： | 三峡水库蓄水使得库岸大量土体长期处于浸泡状态，导致土体软化从而诱发滑坡失稳。为研究长期浸泡对滑坡土体物理-化学-力学性质的影响，以马家沟滑坡原状滑带土为对象开展了浸泡软化试验，通过比较不同浸泡时间滑带土的粒度分布、界限含水率、化学与矿物成分、剪切特性等特征，探讨了滑带土浸泡软化机理。研究结果表明:浸泡过程中滑带土中Ca2+、Mg2+等离子流失较多，但矿物成分无变化；浸泡后滑带土出现阶段性粒度细化现象，液塑限和塑性指数均随黏粒含量增加而增大；随着浸泡时间增加，滑带土应力应变关系在低法向应力下由强软化型变为弱软化型，在高法向应力下由软化型变为硬化型；滑带土抗剪强度参数随着浸泡时间增加呈指数形式降低，黏聚力c降低程度大于内摩擦角φ。研究成果可以为水库滑坡稳定性评价提供理论依据。
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| 关 键 词： | 水库滑坡 滑带土 浸泡软化 物理化学性质 抗剪强度 |
| 收稿时间： | 2020-12-28 |
Effect of long-term immersion in static water on the physical,chemical, and mechanical properties of sliding zone soil in the Three Gorges Reservoir area |
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| Abstract: | The impoundment of the Three Gorges Reservoir has caused a large amount of soil on the bank to be immersed for a long time, which may cause the soil softened and induce instability of landslide.In order to study the effect of long-term immersion on the physical, chemical and mechanical properties of the landslide soil, the immersion softening test is carried out on the undisturbed sliding zone soil of Majiagou landslide.By comparing the particle size distribution, limit moisture content, the characteristics of chemical and mineral composition, shear characteristics, etc., this paper discusses the immersion softening mechanism of sliding zone soil.The results show that ions, such as Ca2+, Mg2+ in the sliding zone soil are largely lost during the immersion process, but the mineral composition does not change.After the immersion, the sliding zone soil appears staged particle size refinement, with which the liquid limit, plastic limit and plasticity index increase.As the immersion time increases, the stress-strain relationship of the sliding zone soil changes from a strong softening type to a weakly softening type under low normal stress, and from a softening type to a hardening type under high normal stress.The shear strength parameters decrease exponentially with the increase of immersion time, and the decrease of cohesion is greater than internal friction angle.The research results can provide a theoretical basis for the stability evaluation of reservoir landslide. |
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