【摘要】：揭示降雨作用下坡面紅土起動的影響因素,建立降雨作用下坡面紅土起動條件,為深入研究云南紅土坡面侵蝕提供參考。根據(jù)紅土特性,結(jié)合降雨作用下坡面紅土的侵蝕過程和現(xiàn)象,采用模型試驗及力學(xué)模型相結(jié)合的研究方法。結(jié)果表明:(1)降雨作用下坡面紅土侵蝕主要呈現(xiàn)濺蝕和結(jié)皮2種現(xiàn)象。(2)紅土黏聚力對坡面紅土顆粒起動有阻礙作用,且抗剪強度越大,坡面紅土顆粒起動的臨界切應(yīng)力也越大。降雨及孔隙水壓力對坡面紅土顆粒起動有促進(jìn)作用,且雨滴密度與雨滴終速越大,降雨的影響也越大;紅土顆粒粒徑越大、雨滴直徑與水深之比越小,降雨的影響也越小。(3)建立了坡面紅土顆粒在聯(lián)結(jié)和松散狀態(tài)下起動的臨界切應(yīng)力計算公式。降雨作用下坡面紅土顆粒起動的臨界切應(yīng)力與紅土顆粒粒徑大小、抗剪強度以及降雨雨滴特性、坡面徑流特性密切相關(guān)。松散狀態(tài)的坡面紅土顆粒在降雨作用下只需很小的徑流切應(yīng)力即可起動。
[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.
【作者單位】： 昆明理工大學(xué)電力工程學(xué)院;
【基金】：國家自然科學(xué)基金項目“云南紅土型水庫庫岸侵蝕失穩(wěn)機理研究,云南紅土型大壩的干濕循環(huán)效應(yīng)研究,污染紅土的宏微觀響應(yīng)及污染物的遷移機制研究”(51269006,51568031,51168022)
【分類號】：S157.1

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