细砂型泥石流诱发机制试验研究及数值分析

发布时间：2018-10-17 21:17

【摘要】：结合先进的数码成像及处理技术,进行精细化的细砂型泥石流模型试验。观察试验过程,将其发展分成入渗、侵蚀、主破坏及破坏后4个阶段。随细砂含量增加,出现主滑动土体时间加快,土体流动性加强,从宏观上表现出流滑型、复合型及分级渐进的不同破坏形态。从细观角度分析,泥石流过程中土体孔隙率先减小后增大,颗粒平均接触数先增大后减小,颗粒长轴定向发生旋转,分布趋于均匀,水土作用过程复杂。基于有限元方法,通过水土特征考虑砂土非饱和土特性,对降雨入渗阶段的砂土渗流进行瞬态分析。砂土内流速矢量方向逐渐从近乎垂直土体表面过渡至坡脚方向,等势线逐渐往坡脚方向偏转,最大渗流速及渗透力出现在三角形坡面中部,预示即将发生的整体滑动破坏,验证试验结果。
[Abstract]:Combined with advanced digital imaging and processing technology, fine sand debris flow model test was carried out. The experimental process was observed and its development was divided into four stages: infiltration, erosion, main failure and after destruction. With the increase of fine sand content, the time of main sliding soil is accelerated, and the soil fluidity is strengthened. From the meso point of view, the soil porosity decreases first and then increases, the average contact number of particles increases first and then decreases, the long axis of particles rotates, the distribution tends to be uniform, and the process of soil and water action is complex. Based on the finite element method and considering the soil and water characteristics of unsaturated sandy soil, the transient analysis of sand seepage in rainfall infiltration stage is carried out. The direction of velocity vector in sandy soil is gradually transitioning from the surface of vertical soil to the direction of slope foot, and the isopotential line gradually deflects towards the direction of slope foot. The maximum seepage velocity and permeability appear in the middle of triangular slope, which indicates that the whole sliding failure will happen soon. Verify the test results.
【作者单位】：福建工程学院土木学院;同济大学地下建筑与工程系;福建省土木工程新技术与信息化重点实验室;地下工程福建省高校重点实验室;
【基金】：国家自然科学基金资助项目(41272296,51504070) 校科研启动基金资助项目(GY-Z14069) 福建省自然科学基金面上项目(2016J01205)
【分类号】：P642.23

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