| 沟岸侧蚀对泥石流不稳定动力过程的影响 |
| |
| 引用本文： | 吕立群,王兆印,崔鹏,徐梦珍.沟岸侧蚀对泥石流不稳定动力过程的影响[J].水科学进展,2018,29(2):213-220. |
| |
| 作者姓名： | 吕立群 王兆印 崔鹏 徐梦珍 |
| |
| 作者单位： | 1.清华大学水沙科学与水利水电工程国家重点实验室, 北京 100084; |
| |
| 基金项目： | 国家自然科学基金资助项目（51479091；41790434） |
| |
| 摘 要： | 泥石流作为非牛顿体，屈服应力大，运动过程通常不稳定。前人建立了许多模型来研究沟床揭底和堰塞体溃决对泥石流不稳定动力过程的影响，沟岸侧蚀对泥石流不稳定动力过程的影响研究较少。通过侧蚀为主的模型和完全底蚀的模型两种水槽实验的对比，针对泥石流的动力过程展开研究。实验发现两种工况条件下泥石流正应力和孔隙水压力随着龙头高度沿程波动性的增长而相应地波动性增大，但侧蚀作用使得这种波动特征更加明显。通过力学分析，证明侧蚀作用导致泥石流龙头的阻力更大，但是龙身颗粒和龙头颗粒的速度差更大，使得龙头附加坡降更大，因此，侧蚀作用使得泥石流龙头的平均速度更快。泥石流龙头浓度和容重的不断增大，使得阻力不断增大，阻力和动力的动态平衡关系是泥石流不稳定运动的原因之一。
|
| 关 键 词： | 侧蚀 底蚀 有效应力 阻力 附加坡降 孔隙水压力 |
| 收稿时间： | 2017-04-27 |
Role of bank erosion on the unsteady dynamics of debris flow motion |
| |
| LYU Liqun,WANG Zhaoyin,CUI Peng,XU Mengzhen.Role of bank erosion on the unsteady dynamics of debris flow motion[J].Advances in Water Science,2018,29(2):213-220. |
| |
| Authors: | LYU Liqun WANG Zhaoyin CUI Peng XU Mengzhen |
| |
| Institution: | 1.State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;2.Mountain Hazard and the Earth's Surface Processes Key Laboratory, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China |
| |
| Abstract: | Debris flow as non-Newtonian fluid has a large yield stress and moved unsteadily. Many models have been established to study the impact of erosion on the unsteady motion, but most of the models were studied the role of the bottom erosion and dam break on the debris flow motion. Less researches studied the role of gully bank erosion on the unsteady dynamic of debris flow. This paper analyzed the role of bank erosion on the debris flow dynamics through flume experiments by bank erosion-dominant and bottom erosion models. The experiments showed that the normal stress and pore water pressure of debris flow increased unsteadily along with the increase of the height of the debris flow head, but the bank erosion made the fluctuation more obvious. The mechanical equation demonstrated that bank erosion enhanced the increase of the frictional resistance. However, the greater velocity difference between the flow body and flow head made the additional gradient of the flow head greater under the bank erosion-dominant condition, so the bank erosion increased the average velocity of debris flow. The dynamic balance between head resistance and power lead to the unsteady motion of debris flow. |
| |
| Keywords: | bank erosion botton erosion effective stress frictional resistance additional gradient pore pressure |
|
| 点击此处可从《水科学进展》浏览原始摘要信息 |
| 点击此处可从《水科学进展》下载免费的PDF全文 |
