降雨作用下坡面红土起动条件研究
发布时间：2018-10-24 15:56
【摘要】：揭示降雨作用下坡面红土起动的影响因素,建立降雨作用下坡面红土起动条件,为深入研究云南红土坡面侵蚀提供参考。根据红土特性,结合降雨作用下坡面红土的侵蚀过程和现象,采用模型试验及力学模型相结合的研究方法。结果表明:(1)降雨作用下坡面红土侵蚀主要呈现溅蚀和结皮2种现象。(2)红土黏聚力对坡面红土颗粒起动有阻碍作用,且抗剪强度越大,坡面红土颗粒起动的临界切应力也越大。降雨及孔隙水压力对坡面红土颗粒起动有促进作用,且雨滴密度与雨滴终速越大,降雨的影响也越大;红土颗粒粒径越大、雨滴直径与水深之比越小,降雨的影响也越小。(3)建立了坡面红土颗粒在联结和松散状态下起动的临界切应力计算公式。降雨作用下坡面红土颗粒起动的临界切应力与红土颗粒粒径大小、抗剪强度以及降雨雨滴特性、坡面径流特性密切相关。松散状态的坡面红土颗粒在降雨作用下只需很小的径流切应力即可起动。
[Abstract]:The influence factors of the red soil starting on the slope surface under rainfall are revealed, and the starting conditions of the red soil on the slope surface under the rainfall action are established, which provides a reference for the further study of the erosion of the red soil slope in Yunnan Province. According to the characteristics of red soil and the erosion process and phenomenon of red soil on slope under rainfall, the research method of model test and mechanical model is adopted. The results show that: (1) the erosion of red soil on slope surface is mainly caused by splash erosion and crust, and (2) the cohesive force of red soil hinders the starting of red soil particles on slope surface, and the higher the shear strength, the greater the critical shear stress of the starting of red soil particles on slope surface. Rainfall and pore water pressure can promote the starting of laterite particles on the slope, and the bigger the raindrop density and the final velocity of raindrop, the greater the effect of rainfall, the larger the diameter of laterite particle, the smaller the ratio of raindrop diameter to water depth. The effect of rainfall is also smaller. (3) the formula of critical shear stress of red soil particle starting under the condition of joint and loose state is established. The critical shear stress is closely related to the particle size, shear strength, rainfall raindrop characteristics and runoff characteristics. Under the action of rainfall, the loose laterite particles can be started with only small runoff shear stress.
【作者单位】： 昆明理工大学电力工程学院;
【基金】：国家自然科学基金项目“云南红土型水库库岸侵蚀失稳机理研究,云南红土型大坝的干湿循环效应研究,污染红土的宏微观响应及污染物的迁移机制研究”(51269006,51568031,51168022)
【分类号】：S157.1
本文编号：2291839
[Abstract]:The influence factors of the red soil starting on the slope surface under rainfall are revealed, and the starting conditions of the red soil on the slope surface under the rainfall action are established, which provides a reference for the further study of the erosion of the red soil slope in Yunnan Province. According to the characteristics of red soil and the erosion process and phenomenon of red soil on slope under rainfall, the research method of model test and mechanical model is adopted. The results show that: (1) the erosion of red soil on slope surface is mainly caused by splash erosion and crust, and (2) the cohesive force of red soil hinders the starting of red soil particles on slope surface, and the higher the shear strength, the greater the critical shear stress of the starting of red soil particles on slope surface. Rainfall and pore water pressure can promote the starting of laterite particles on the slope, and the bigger the raindrop density and the final velocity of raindrop, the greater the effect of rainfall, the larger the diameter of laterite particle, the smaller the ratio of raindrop diameter to water depth. The effect of rainfall is also smaller. (3) the formula of critical shear stress of red soil particle starting under the condition of joint and loose state is established. The critical shear stress is closely related to the particle size, shear strength, rainfall raindrop characteristics and runoff characteristics. Under the action of rainfall, the loose laterite particles can be started with only small runoff shear stress.
【作者单位】： 昆明理工大学电力工程学院;
【基金】：国家自然科学基金项目“云南红土型水库库岸侵蚀失稳机理研究,云南红土型大坝的干湿循环效应研究,污染红土的宏微观响应及污染物的迁移机制研究”(51269006,51568031,51168022)
【分类号】：S157.1
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