降雨作用下土体细颗粒迁移特征及其对崩塌的影响

发布时间：2018-03-10 06:05

本文选题：水槽试验　切入点：颗粒迁移　出处：《工程科学与技术》2017年S2期 　论文类型：期刊论文

【摘要】：为研究坡面土体崩塌的时空特征,进行人工降雨水槽试验,在不同降雨强度下,观测土体细颗粒的迁移、土体崩塌的时间序列和相应的孔隙水压力变化曲线,并对崩塌体、迁移土体和渗流浆体进行时间序列取样。试验结束后对所取样本进行土体颗粒分析,并结合标度分布参数,对比坡面相同位置不同深度土体试验前后颗粒级配的变化,从随机性的角度分析土体的颗分参数与强度之间的关系。结果表明:在降雨作用下,坡体中的细颗粒会发生迁移,使土体结构发生改变。细颗粒在坡体内部某一位置集聚,引起孔隙水压力增大;在水力梯度较大和细颗粒容易积聚的区域,更容易发生坡面崩塌破坏,且崩塌破坏序列呈现出随机分布的特征;坡脚处流出的细颗粒含量随时间波动越大,坡体结构越不稳定,坡面崩塌破坏现象越明显;土体的剪切强度和内摩擦角随细颗粒含量的增大而减小;坡面土体颗粒的空间分布决定了土体强度的空间分布,天然坡面上的土体颗粒组成并非一成不变;土体的颗分参数μ值服从Weibull分布,坡面土体剪切强度和内摩擦角均具有Weibull随机分布特征,最终导致坡面土体崩塌在时间和空间上呈现随机性。
[Abstract]:In order to study the temporal and spatial characteristics of slope soil collapse, the artificial rainfall flume test was carried out. Under different rainfall intensity, the time series of soil mass collapse, the time series of soil collapse and the corresponding curve of pore water pressure were observed. At the end of the test, the samples were analyzed by particle analysis, and the change of particle gradation before and after the test was compared with the parameters of scale distribution. The relationship between the particle parameters and the strength of the soil is analyzed from the randomness point of view. The results show that the fine particles in the slope will migrate and change the soil structure under the action of rainfall, and the fine particles gather in a certain position of the slope body. In the area where the hydraulic gradient is large and the fine particles are easy to accumulate, the slope collapse is more likely to occur, and the collapse failure sequence shows the characteristics of random distribution. The larger the fluctuation of fine particle content at the foot of slope, the more unstable the structure of slope body, the more obvious the phenomenon of slope collapse and failure, the shear strength and the angle of internal friction of soil decrease with the increase of fine particle content. The spatial distribution of soil particles determines the spatial distribution of soil strength. The shear strength and internal friction angle of slope soil have the characteristics of Weibull random distribution, which leads to the randomness of soil collapse in time and space.
【作者单位】：西南交通大学土木工程学院;中国科学院山地灾害与地表过程重点实验室;中国科学院水利部成都山地灾害与环境研究所;长江重庆航运工程勘察设计院;福建省建筑设计研究院;
【基金】：国家自然科学基金资助项目(41471011) 中国科学院西部之光项目资助(Y5R2040040)
【分类号】：TU43

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