黄土高原地区鱼鳞坑坡面侵蚀演化过程及水力学特征
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摘要
为明确鱼鳞坑坡面抗侵蚀演化过程及其水流水力学特性,采用间歇性人工模拟降雨实验,对鱼鳞坑坡面水流水力学特性以及阻力规律进行了系统分析。结果表明:(1)鱼鳞坑坡面侵蚀演化过程表现为:雨滴溅蚀—片蚀—股流冲刷—跌坑—细沟侵蚀—下切侵蚀—溯源侵蚀—崩塌。(2)随着降雨历时的增加,由于鱼鳞坑的层层拦截与蓄满,其下方的坡面径流流速、水深均呈波动式增长趋势,坑内出现旋涡,坡面径流呈现断续股流。降雨累积历时为58 min左右,总降雨量达到87 mm时,鱼鳞坑侵蚀量急剧增加,拦蓄径流作用失效。(3)五场降雨过程中,上坡和中坡水流流态为层流,下坡由于鱼鳞坑蓄满后径流出现波动,水流流态由层流变为紊流且时而为缓流时而为急流。(4)鱼鳞坑坡面水流阻力来源于降雨阻力、颗粒阻力、形态阻力叠加,在整个降雨过程中阻力总和呈下降趋势;其中,受地形高低起伏、地表糙度的影响,形态阻力一直居于主导地位。
【Objective】Fish-scale pits measure is a widespread and typical soil and water conservation engineering measure in Loess Plateau that can be used to impound runoff and reduce the soil erosion mass and create a good water condition for vegetation growth.In order to clarify erosion evolution processes and flow hydraulic characteristics of fish-scale pies measure under the condition of continuous rainfall.【Method】In this paper,we analysed the erosion evolution with 3 D laser scanner and realized graphical and digital process of erosion evolution on fish-scale pies slope by laboratory five rainfalls simulation.【Result】The results showed that:(1)Dynamic process of fish-scale pits erosion could be presented as splash erosion-sheet erosion-drop pit-rill erosion-longitudinal erosion-headward erosion-collapse.By the end of the 5 th rainfall,the largest rill length、width and depth respectively increased to 80 cm、22 cm and 7.8 cm.During the first two rainfalls,fish-scale pits played a significant role in water storage and silt detention,sheet erosion and rill erosion occurred at some parts of slope;Later,due to excessive water of pits and high moisture content of side slope,leading to collapse phenomenon in pits and longitudinal erosion,rill headward erosion at down-slope,also increased erosion.(2)As the rainfall duration increases,the down-slope velocity and runoff depth were increased with fluctuation because the rainfall could be hold up in pits.What's more,vortex accurred in pits and streams scour accurred in slope surface.The order of the average flow velocity and the average water depth is:the up-slope>mid-slope>down-slope.The velocity and depth in rill were significantly larger the slope.The Reynolds number of up-slope and mid-slope was less than 500,and for down-slope,it was over 500 at the end of 5 th rainfall.When rainfall accumulated duration reached 58 min and rainfall increased to 87 mm,erosion increased dramatically.Fish-scale pits unable to played a positive effect.(3)During five rainfalls,the upslope and mid-slope flow regime was laminar flow.With the down-slope pits being filled,slope runoff fluctuated greatly,down-slope flow became turbulent flow from laminar flow and changed between subcritical flow and supercritical flow.(4)Resistance mainly comes from rain,grain and form resistance,and form resistance that orginated from the rugged slope was the dominant resistance.Due to the callapse、scour and fluctuant change of terrain,resistance decreased with rainfall accumulation duration accompanied by minor fluctuations.The order of resistance was form resistance> grain resistance> rain resistance.【Conclusion】The study was of momentous significance to clarify the fish-scale pit slope erosion and its mechanism,also provides theory basis and decision support for loess plateau area to layout fish-scale pits reasonably.Only if we layout fish-scale pits reasonably in Loess Plateau area can we improve and keep soil moisture greatly.
【Objective】Fish-scale pits measure is a widespread and typical soil and water conservation engineering measure in Loess Plateau that can be used to impound runoff and reduce the soil erosion mass and create a good water condition for vegetation growth.In order to clarify erosion evolution processes and flow hydraulic characteristics of fish-scale pies measure under the condition of continuous rainfall.【Method】In this paper,we analysed the erosion evolution with 3 D laser scanner and realized graphical and digital process of erosion evolution on fish-scale pies slope by laboratory five rainfalls simulation.【Result】The results showed that:(1)Dynamic process of fish-scale pits erosion could be presented as splash erosion-sheet erosion-drop pit-rill erosion-longitudinal erosion-headward erosion-collapse.By the end of the 5 th rainfall,the largest rill length、width and depth respectively increased to 80 cm、22 cm and 7.8 cm.During the first two rainfalls,fish-scale pits played a significant role in water storage and silt detention,sheet erosion and rill erosion occurred at some parts of slope;Later,due to excessive water of pits and high moisture content of side slope,leading to collapse phenomenon in pits and longitudinal erosion,rill headward erosion at down-slope,also increased erosion.(2)As the rainfall duration increases,the down-slope velocity and runoff depth were increased with fluctuation because the rainfall could be hold up in pits.What's more,vortex accurred in pits and streams scour accurred in slope surface.The order of the average flow velocity and the average water depth is:the up-slope>mid-slope>down-slope.The velocity and depth in rill were significantly larger the slope.The Reynolds number of up-slope and mid-slope was less than 500,and for down-slope,it was over 500 at the end of 5 th rainfall.When rainfall accumulated duration reached 58 min and rainfall increased to 87 mm,erosion increased dramatically.Fish-scale pits unable to played a positive effect.(3)During five rainfalls,the upslope and mid-slope flow regime was laminar flow.With the down-slope pits being filled,slope runoff fluctuated greatly,down-slope flow became turbulent flow from laminar flow and changed between subcritical flow and supercritical flow.(4)Resistance mainly comes from rain,grain and form resistance,and form resistance that orginated from the rugged slope was the dominant resistance.Due to the callapse、scour and fluctuant change of terrain,resistance decreased with rainfall accumulation duration accompanied by minor fluctuations.The order of resistance was form resistance> grain resistance> rain resistance.【Conclusion】The study was of momentous significance to clarify the fish-scale pit slope erosion and its mechanism,also provides theory basis and decision support for loess plateau area to layout fish-scale pits reasonably.Only if we layout fish-scale pits reasonably in Loess Plateau area can we improve and keep soil moisture greatly.
引文
[1]李萍,朱清科,赵磊磊,等.黄土丘陵沟壑区鱼鳞坑雨季土壤水分状况.农业工程学报,2011,27(7):76—81Li P,Zhu Q K,Zhao L L,et al.Soil moisture of fishscale pit during rainy season in loess hi1ly and gully region(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2011,27(7):76—81
[2]歌丽巴,王彬,张会兰,等.坡面水保措施下土壤水分特征及对坡体稳定性的作用.土壤通报,2014,45(5):1225—1232Ge L B,Wang B,Zhang H L,et al.Variations of soil moisture under soil and water conservation measures and the corresponding effects on slope stability(In Chinese).Chinese Journal of Soil Science,2014,45(5):1225—1232
[3]吴淑芳.坡面径流调控效应及其机理研究.陕西杨凌:西北农林科技大学,2006Wu S F.Study on the effect mechanism of the slope runoff regulation(In Chinese).Yangling,Shaanxi:Northwest A&F University,2006
[4]李萍,朱清科,王晶,等.半干旱黄土丘陵沟壑区不同规格鱼鳞坑集水效果研究.灌溉排水学报,2011,30(5):91—94Li P,Zhu Q K,Wang J,et al.Catchment effect of fish-scale pits with different specification in semi-arid hilly and gully Loess Plateau(In Chinese).Journal of Irrigation and Drainage,2011,30(5):91—94
[5]朱聿申,陈宇轩,查同刚,等.大鱼鳞坑双苗造林技术在黄土沟壑区的应用效果.干旱区研究,2016,33(3):560—568Zhu Y S,Chen Y X,Zha T G,et al.Application of double-seedling afforestation technique in big fish-scale pits in the loess gully area(In Chinese).Arid Zone Research,2016,33(3):560—568
[6]孙军.黄土高原延河流域不同土地利用类型水土保持效应研究.长沙:湖南农业大学,2008Sun J.Impacts of different land use types on soil and water conservation in Yanhe River drainage area on the Loess Plateau(In Chinese).Changsha:Hunan Agricultural University,2008
[7]王青宁,衣学慧,王晗生,等.黄土坡面植被重建鱼鳞坑整地的土壤水分特征.土壤通报,2015,46(4):866—872Wang Q N,Yi X H,Wang H S,et al.Soil moisture regime of fish-scale pits for land preparation engineering in loess slope revegetation(In Chinese).Chinese Journal of Soil Science,2015,46(4):866—872
[8]李虹辰.黄土丘陵区旱作枣园鱼鳞坑与覆盖措施土壤水分动态效应研究.陕西杨凌:西北农林科技大学水土保持研究所,2014Li H C.Study on spatio-temporal distribution and utilization of soil moisture under scale-like pit and mulching measures of the Loess hilly region(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2014
[9]吴淑芳,吴普特,宋维秀,等.黄土坡面径流剥离土壤的水动力过程研究.土壤学报,2010,47(2):223—228Wu S F,Wu P T,Song W X,et al.Hydrodynamic process of soil detachment by surface runoff on Loess slope(In Chinese).Acta Pedologica Sinica,2010,47(2):223—228
[10]唐小娟.坡地分段雨水集蓄利用技术试验研究.陕西杨凌:西北农林科技大学水土保持研究所,2004Tang X J.Experimental study on rainwater catchment utilization technology in slope partition(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2004
[11]原立峰,吴淑芳,刘星飞,等.基于元胞自动机的黄土坡面细沟侵蚀模型研究.土壤学报,2012,49(5):1043—1049Yuan L F,Wu S F,Liu X F,et al.Study on loess hill slope rill erosion model based on cellular automata(In Chinese).Acta Pedologica Sinica,2012,49(5):1043—1049
[12]严冬春,王一峰,文安邦,等.紫色土坡耕地细沟发育的形态演变.山地学报,2011,29(4):469—473Yan D C,Wang Y F,Wen A B,et al.Configuration evolvement of rill development on purple slopeland(In Chinese).Journal of Mountain Science,2011,29(4):469—473
[13]和继军,孙莉英,李君兰,等.缓坡面细沟发育过程及水沙关系的室内试验研究.农业工程学报,2012,28(10):138—144He J J,Sun L Y,Li J L,et al.Experimental study on rill evolution process and runoff-sediment relationship for gentle slope(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2012,28(10):138—144
[14]霍云云,吴淑芳,冯浩,等.基于三维激光扫描仪的坡面细沟侵蚀动态过程研究.中国水土保持科学,2011,9(2):32—46Huo Y Y,Wu S F,Feng H,et al.Dynamic process of slope rill erosion based on three-dimensional laser scanner(In Chinese).Science of Soil and Water Conservation,2011,9(2):32—46
[15]吴淑芳,刘政鸿,霍云云,等.黄土坡面细沟侵蚀发育过程与模拟.土壤学报,2015,52(1):48—56Wu S F,Liu Z H,Huo Y Y,et al.Development of rill erosion on loess slope and its simulation(In Chinese).Acta Pedologica Sinica,2015,52(1):48—56
[16]Abrahams A D,Parsons A J,Hirsch P J.Field and laboratory studies of resistance to inter rill overland flow on semi-arid hillslopes,Southern Arizona//Parsons A J,Abrahams A D.Overland flow:Hydraulics and erosion mechanics.London:UCL Press,1992:1—23
[17]张颖,牛健植,谢宝元,等.森林植被对坡面土壤水蚀作用的动力学机理.生态学报,2008,28(10):5084—5094Zhang Y,Niu J Z,Xie B Y,et al.Dynamics mechanism of the effect of forest vegetation on hill-slope water erosion(In Chinese).Acta Ecologica Sinica,2008,28(10):5084—5094
[18]郑良勇,李占斌,李鹏.植被保持水土有效性研究进展.水土保持学报,2002,9(1):76—79Zheng L Y,Li Z B,Li P.Advances in researches of the effectiveness for vegetation conserving soil and water(In Chinese).Journal of Soil and Water Conservation,2002,9(1):76—79
[19]赵春红.坡面侵蚀性降雨径流水动力学特性及其对输沙的影响.陕西杨凌:西北农林科技大学水土保持研究所,2014Zhao C H.Slope and erosive rainfall runoff hydraulics and its effect on sediment transport(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2014
[20]肖培青,郑粉莉,姚文艺.坡沟系统坡面径流流态及水力学参数特征研究.水科学进展,2009,20(2):236—240Xiao P Q,Zheng F L,Yao W Y.Flow pattern and hydraulic parameter characteristics in hillslopegullyslope system(In Chinese).Advances in Water Sciences,2009,20(2):236—240
[21]张宽地,王光谦,吕宏兴,等.模拟降雨条件下坡面流水动力学特性研究.水科学进展,2012,23(2):229—235Zhang K D,Wang G Q,LüH X,et al.Experimental study of shallow flow hydraulics on a hillslope under artificial rainfall conditions(In Chinese).Advances in Water Sciences,2012,23(2):229—235
[22]张宽地,王光谦,孙晓敏,等.模拟植被覆盖条件下坡面流水动力学特性.水科学进展,2014,25(6):825—834Zhang K D,Wang G Q,Sun X M,et al.Hydraulic characteristic of overland flow under different vegetation coverage(In Chinese).Advances in Water Sciences,2014,25(6):825—834
[2]歌丽巴,王彬,张会兰,等.坡面水保措施下土壤水分特征及对坡体稳定性的作用.土壤通报,2014,45(5):1225—1232Ge L B,Wang B,Zhang H L,et al.Variations of soil moisture under soil and water conservation measures and the corresponding effects on slope stability(In Chinese).Chinese Journal of Soil Science,2014,45(5):1225—1232
[3]吴淑芳.坡面径流调控效应及其机理研究.陕西杨凌:西北农林科技大学,2006Wu S F.Study on the effect mechanism of the slope runoff regulation(In Chinese).Yangling,Shaanxi:Northwest A&F University,2006
[4]李萍,朱清科,王晶,等.半干旱黄土丘陵沟壑区不同规格鱼鳞坑集水效果研究.灌溉排水学报,2011,30(5):91—94Li P,Zhu Q K,Wang J,et al.Catchment effect of fish-scale pits with different specification in semi-arid hilly and gully Loess Plateau(In Chinese).Journal of Irrigation and Drainage,2011,30(5):91—94
[5]朱聿申,陈宇轩,查同刚,等.大鱼鳞坑双苗造林技术在黄土沟壑区的应用效果.干旱区研究,2016,33(3):560—568Zhu Y S,Chen Y X,Zha T G,et al.Application of double-seedling afforestation technique in big fish-scale pits in the loess gully area(In Chinese).Arid Zone Research,2016,33(3):560—568
[6]孙军.黄土高原延河流域不同土地利用类型水土保持效应研究.长沙:湖南农业大学,2008Sun J.Impacts of different land use types on soil and water conservation in Yanhe River drainage area on the Loess Plateau(In Chinese).Changsha:Hunan Agricultural University,2008
[7]王青宁,衣学慧,王晗生,等.黄土坡面植被重建鱼鳞坑整地的土壤水分特征.土壤通报,2015,46(4):866—872Wang Q N,Yi X H,Wang H S,et al.Soil moisture regime of fish-scale pits for land preparation engineering in loess slope revegetation(In Chinese).Chinese Journal of Soil Science,2015,46(4):866—872
[8]李虹辰.黄土丘陵区旱作枣园鱼鳞坑与覆盖措施土壤水分动态效应研究.陕西杨凌:西北农林科技大学水土保持研究所,2014Li H C.Study on spatio-temporal distribution and utilization of soil moisture under scale-like pit and mulching measures of the Loess hilly region(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2014
[9]吴淑芳,吴普特,宋维秀,等.黄土坡面径流剥离土壤的水动力过程研究.土壤学报,2010,47(2):223—228Wu S F,Wu P T,Song W X,et al.Hydrodynamic process of soil detachment by surface runoff on Loess slope(In Chinese).Acta Pedologica Sinica,2010,47(2):223—228
[10]唐小娟.坡地分段雨水集蓄利用技术试验研究.陕西杨凌:西北农林科技大学水土保持研究所,2004Tang X J.Experimental study on rainwater catchment utilization technology in slope partition(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2004
[11]原立峰,吴淑芳,刘星飞,等.基于元胞自动机的黄土坡面细沟侵蚀模型研究.土壤学报,2012,49(5):1043—1049Yuan L F,Wu S F,Liu X F,et al.Study on loess hill slope rill erosion model based on cellular automata(In Chinese).Acta Pedologica Sinica,2012,49(5):1043—1049
[12]严冬春,王一峰,文安邦,等.紫色土坡耕地细沟发育的形态演变.山地学报,2011,29(4):469—473Yan D C,Wang Y F,Wen A B,et al.Configuration evolvement of rill development on purple slopeland(In Chinese).Journal of Mountain Science,2011,29(4):469—473
[13]和继军,孙莉英,李君兰,等.缓坡面细沟发育过程及水沙关系的室内试验研究.农业工程学报,2012,28(10):138—144He J J,Sun L Y,Li J L,et al.Experimental study on rill evolution process and runoff-sediment relationship for gentle slope(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2012,28(10):138—144
[14]霍云云,吴淑芳,冯浩,等.基于三维激光扫描仪的坡面细沟侵蚀动态过程研究.中国水土保持科学,2011,9(2):32—46Huo Y Y,Wu S F,Feng H,et al.Dynamic process of slope rill erosion based on three-dimensional laser scanner(In Chinese).Science of Soil and Water Conservation,2011,9(2):32—46
[15]吴淑芳,刘政鸿,霍云云,等.黄土坡面细沟侵蚀发育过程与模拟.土壤学报,2015,52(1):48—56Wu S F,Liu Z H,Huo Y Y,et al.Development of rill erosion on loess slope and its simulation(In Chinese).Acta Pedologica Sinica,2015,52(1):48—56
[16]Abrahams A D,Parsons A J,Hirsch P J.Field and laboratory studies of resistance to inter rill overland flow on semi-arid hillslopes,Southern Arizona//Parsons A J,Abrahams A D.Overland flow:Hydraulics and erosion mechanics.London:UCL Press,1992:1—23
[17]张颖,牛健植,谢宝元,等.森林植被对坡面土壤水蚀作用的动力学机理.生态学报,2008,28(10):5084—5094Zhang Y,Niu J Z,Xie B Y,et al.Dynamics mechanism of the effect of forest vegetation on hill-slope water erosion(In Chinese).Acta Ecologica Sinica,2008,28(10):5084—5094
[18]郑良勇,李占斌,李鹏.植被保持水土有效性研究进展.水土保持学报,2002,9(1):76—79Zheng L Y,Li Z B,Li P.Advances in researches of the effectiveness for vegetation conserving soil and water(In Chinese).Journal of Soil and Water Conservation,2002,9(1):76—79
[19]赵春红.坡面侵蚀性降雨径流水动力学特性及其对输沙的影响.陕西杨凌:西北农林科技大学水土保持研究所,2014Zhao C H.Slope and erosive rainfall runoff hydraulics and its effect on sediment transport(In Chinese).Yangling,Shaanxi:Institute of Soil and Water Conservation,Northwest A&F University,2014
[20]肖培青,郑粉莉,姚文艺.坡沟系统坡面径流流态及水力学参数特征研究.水科学进展,2009,20(2):236—240Xiao P Q,Zheng F L,Yao W Y.Flow pattern and hydraulic parameter characteristics in hillslopegullyslope system(In Chinese).Advances in Water Sciences,2009,20(2):236—240
[21]张宽地,王光谦,吕宏兴,等.模拟降雨条件下坡面流水动力学特性研究.水科学进展,2012,23(2):229—235Zhang K D,Wang G Q,LüH X,et al.Experimental study of shallow flow hydraulics on a hillslope under artificial rainfall conditions(In Chinese).Advances in Water Sciences,2012,23(2):229—235
[22]张宽地,王光谦,孙晓敏,等.模拟植被覆盖条件下坡面流水动力学特性.水科学进展,2014,25(6):825—834Zhang K D,Wang G Q,Sun X M,et al.Hydraulic characteristic of overland flow under different vegetation coverage(In Chinese).Advances in Water Sciences,2014,25(6):825—834