农业工程学报
農業工程學報
농업공정학보
2014年
1期
73-80
,共8页
土壤%流量%水动力学%结皮%水流功率%水流剪切力%阻力系数
土壤%流量%水動力學%結皮%水流功率%水流剪切力%阻力繫數
토양%류량%수동역학%결피%수류공솔%수류전절력%조력계수
soil%flow%hydrodynamics%crusts%stream power%shear stress%resistance coefficient
为了深入探讨土壤结皮对侵蚀的影响机制以及两者之间的关系，以10°坡为例，在变流量（1.0，1.4，2.0，2.4和2.8 L/min）条件下进行室内冲刷试验，研究土壤结皮坡面径流水动力学特征（平均流速、平均径流深度、雷诺数、水流剪切力、水流功率、阻力系数）并分析坡面流水动力学参数与土壤侵蚀量的关系。结果表明，土壤结皮对坡面流水动力学参数影响显著。土壤结皮坡面雷诺数始终小于500，坡面流流态为层流；土壤结皮坡面具有较大坡面流流速，较小径流深度、水流剪切力和水流功率。结皮坡面的土壤侵蚀量明显低于无结皮坡面的土壤侵蚀量。土壤侵蚀量与坡面水动力学参数相关关系显著（相关系数R>0.90），土壤侵蚀量与雷诺数呈线性正相关，与水流剪切力、水流功率的对数呈线性正相关，与阻力系数呈线性负相关。因此，在本研究中，单纯从径流冲刷侵蚀的角度土壤结皮的存在有利于减小坡面土壤侵蚀量。由于降雨因素对土壤结皮的侵蚀效应影响较大，将雨滴打击与径流冲刷相结合才能更好地研究土壤结皮对侵蚀的影响机制。
為瞭深入探討土壤結皮對侵蝕的影響機製以及兩者之間的關繫，以10°坡為例，在變流量（1.0，1.4，2.0，2.4和2.8 L/min）條件下進行室內遲刷試驗，研究土壤結皮坡麵徑流水動力學特徵（平均流速、平均徑流深度、雷諾數、水流剪切力、水流功率、阻力繫數）併分析坡麵流水動力學參數與土壤侵蝕量的關繫。結果錶明，土壤結皮對坡麵流水動力學參數影響顯著。土壤結皮坡麵雷諾數始終小于500，坡麵流流態為層流；土壤結皮坡麵具有較大坡麵流流速，較小徑流深度、水流剪切力和水流功率。結皮坡麵的土壤侵蝕量明顯低于無結皮坡麵的土壤侵蝕量。土壤侵蝕量與坡麵水動力學參數相關關繫顯著（相關繫數R>0.90），土壤侵蝕量與雷諾數呈線性正相關，與水流剪切力、水流功率的對數呈線性正相關，與阻力繫數呈線性負相關。因此，在本研究中，單純從徑流遲刷侵蝕的角度土壤結皮的存在有利于減小坡麵土壤侵蝕量。由于降雨因素對土壤結皮的侵蝕效應影響較大，將雨滴打擊與徑流遲刷相結閤纔能更好地研究土壤結皮對侵蝕的影響機製。
위료심입탐토토양결피대침식적영향궤제이급량자지간적관계，이10°파위례，재변류량（1.0，1.4，2.0，2.4화2.8 L/min）조건하진행실내충쇄시험，연구토양결피파면경류수동역학특정（평균류속、평균경류심도、뢰낙수、수류전절력、수류공솔、조력계수）병분석파면류수동역학삼수여토양침식량적관계。결과표명，토양결피대파면류수동역학삼수영향현저。토양결피파면뢰낙수시종소우500，파면류류태위층류；토양결피파면구유교대파면류류속，교소경류심도、수류전절력화수류공솔。결피파면적토양침식량명현저우무결피파면적토양침식량。토양침식량여파면수동역학삼수상관관계현저（상관계수R>0.90），토양침식량여뢰낙수정선성정상관，여수류전절력、수류공솔적대수정선성정상관，여조력계수정선성부상관。인차，재본연구중，단순종경류충쇄침식적각도토양결피적존재유리우감소파면토양침식량。유우강우인소대토양결피적침식효응영향교대，장우적타격여경류충쇄상결합재능경호지연구토양결피대침식적영향궤제。
We investigated the effects of soil crusts on soil erosion mechanism and their relationship, and series of the runoff scouring experiments were conducted in the Soil and Water Conservation Engineering Laboratory in Northwest A&F University. Two soil surface conditions-the crusts surface and the no crusts surface (control) were explored in our studies. The slope of the scouring trough was set up at 10°(17.6%), five flow rates (1.0, 1.4, 2.0, 2.4 and 2.8 L/min) were used to scour the soil. The flow velocity was measured by the staining method. The flow width was measured by a ruler on the top, central and bottom of slope. The water temperature was measured by a thermometer. The sediment discharge rate was collected at the end of the scouring trough. Then the hydrodynamic characteristics of overland flow (the average flow velocity, the average flow depth, the Reynolds number, the shear stress, the stream power and the resistance coefficient) and the relation between hydrodynamic characteristics of overland flow and soil erosion were analyzed. There was a significant effect of soil crusts on hydrodynamic characteristics. The Reynolds number under soil crusts surface was less than 500, which meant the overland flow was laminar flow. The flow velocity was greater on soil crusts surface than that without soil crusts surface, while the flow depth, the shear stress, the stream power and the soil erosion was much lower on soil crusts surface than that without soil crusts surface. The correlation between soil erosion and hydrodynamic characteristics of overland flow was significant (Regression coefficient R>0.90). Soil erosion had a positive linear correlation with Reynolds number and the logarithm of shear stress and stream power, while had a negative liner correlation with resistance coefficient. Therefore, the existence of soil crusts is helpful to reduce soil erosion from the runoff perspective. Due to the importance of the rainfall factor, it is better to study the effect of soil crusts on soil erosion by combing the raindrop splashing and runoff souring factors.
