三峡水库消落带淹水——落干交替下紫色土力学特性变化模拟

发布时间：2019-06-10 07:04

【摘要】：三峡水库消落带在高压淹水浸泡和干湿交替作用下,土壤力学特性必然发生变化,影响土体抗侵蚀性能,破坏库岸稳定性。目前对消落带土壤力学特性变化及其对淹水—落干驱动的响应尚不明确。以三峡水库消落带广泛分布的紫色土为研究对象,模拟水压作用和淹没—出露交替过程,研究紫色土应力—应变和抗剪强度参数对高压淹水和干湿交替作用的响应。结果表明:水柱压力、干湿交替次数和干湿交替幅度都能显著驱动紫色土力学特性发生变化。与对照组相比,随着水柱压力增加,紫色土刚度逐渐增强,黏聚力降低幅度变小,内摩擦角增大。随干湿交替次数增加,紫色土刚度逐渐减小;内摩擦角有所增大,黏聚力的变化趋势与之相反,且随干湿交替次数的增加而显著降低。随干湿交替幅度增加,抗剪强度迅速降低(相同围压下),黏聚力增大,内摩擦角降低;与对照组相比,干湿交替幅度越小,土壤的内摩擦角增大越多,黏聚力降低越多。
[Abstract]:Under the action of high pressure flooding and alternation of dry and wet, the soil mechanical properties of the three Gorges Reservoir will inevitably change, which will affect the erosion resistance of soil and destroy the stability of reservoir bank. At present, the response to the change of soil mechanical properties and its response to flooding-drying drive in the falling zone is not clear. Taking purple soil widely distributed in the collapse zone of the three Gorges Reservoir as the research object, the response of stress-strain and shear strength parameters of purple soil to the alternation of high pressure flooding and dry and wet water was studied by simulating the process of water pressure and the alternation of inundation and dew. The results show that the pressure of water column, the number of dry and wet alternation and the amplitude of dry and wet alternation can significantly drive the change of mechanical properties of purple soil. Compared with the control group, with the increase of water column pressure, the stiffness of purple soil increased gradually, the cohesion decreased, and the internal friction angle increased. With the increase of the number of dry and wet alternation, the stiffness of purple soil decreases gradually, the internal friction angle increases, the trend of cohesion is opposite, and decreases significantly with the increase of the number of dry and wet alternation. With the increase of dry and wet alternation amplitude, the shear strength decreases rapidly (under the same confining pressure), the cohesion increases and the internal friction angle decreases. Compared with the control group, the smaller the dry and wet alternation amplitude is, the more the internal friction angle of soil increases and the more the cohesion decreases.
【作者单位】：中国科学院水利部成都山地灾害与环境研究所山地表生过程与生态调控重点实验室;中国科学院大学;四川大学建筑与环境学院;
【基金】：国家自然科学基金项目(41571278,41301290) 中国科学院科技服务网络计划项目(KFJ-SW-STS-175);中国科学院“西部之光”人才培养引进计划(2013&2016)
【分类号】：S157

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