马卡山不同植被群落斜坡土体中根土环隙导流特性
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摘要
根土环隙作为一种新型的特殊土壤大孔隙类型,在植被发育斜坡土体降雨入渗过程中发挥着重要作用。采集呈贡实验区高盖度不同植被群落斜坡土体,基于水分穿透法,获取大孔隙特征参数,结合套管数学模型,进行了土体中根土环隙的导流特性研究,结果表明:木本和草本植被群落土体根土环隙尺寸范围分别为0.62~1.02 mm、0.67~1.12 mm,且前者土体各层环隙尺度均小于后者。两种植被群落土体中根土环隙流道u/u_m的最大值均随深度增加而增大,但大小基本一致;深度范围内,土体各层u/u_m达到最大值时的r值提前,且木本土体各层相应r值均大于草本;根系及环隙尺寸的差异是形成其特征的主要原因。相同流道数量及雷诺数条件下,平均流速、最大流速及环隙导流贡献率均随深度增加而增大,流量则反之,且木本土体各层流速、流量及贡献率均大于草本。
As a new type of special soil macropore types, root-soil annulus plays an important role in the process of rainfall infiltration of soil on a vegetated slope. Soils were collected in the high coverage slopes of different vegetation communities in the experimental area of Chenggong, the characteristic parameters of the macropores were obtained by using the moisture breakthrough method, then the flow characteristics of the root-soil annulus were studied combined with mathematical model of annular tubes. Results showed there was little difference between the sizes of the root-soil annulus of the woody and herbaceous vegetation communities, which were distributed in the ranges of 0.62-1.02 mm and 0.67-1.12 mm, respectively, and the annulus scales in different layers in the former vegetation community were smaller than those of the latter. The maximum values of u/u_mof root-soil annulus channels in the soils under the two vegetation communities increased with depth, however, the value was nearly the same; within the scope of the depth, the r value was in advance when u/u_m of the soil layer reached the maximum value, and the corresponding r values of all layers of woody soil were greater than those of the herb. The differences between the size of root system and the annulus were the main reasons for the formation of the above characteristics. Under the same of the number of fluid channels and Reynolds number, the average flow velocity, maximum velocity and flow contribution rate of the annular increased with depth, however, the situation of flow was opposite. In addition, the flow rate, flow and contribution rate of woody plant soil in each layer were higher than those of herb plant soil.
As a new type of special soil macropore types, root-soil annulus plays an important role in the process of rainfall infiltration of soil on a vegetated slope. Soils were collected in the high coverage slopes of different vegetation communities in the experimental area of Chenggong, the characteristic parameters of the macropores were obtained by using the moisture breakthrough method, then the flow characteristics of the root-soil annulus were studied combined with mathematical model of annular tubes. Results showed there was little difference between the sizes of the root-soil annulus of the woody and herbaceous vegetation communities, which were distributed in the ranges of 0.62-1.02 mm and 0.67-1.12 mm, respectively, and the annulus scales in different layers in the former vegetation community were smaller than those of the latter. The maximum values of u/u_mof root-soil annulus channels in the soils under the two vegetation communities increased with depth, however, the value was nearly the same; within the scope of the depth, the r value was in advance when u/u_m of the soil layer reached the maximum value, and the corresponding r values of all layers of woody soil were greater than those of the herb. The differences between the size of root system and the annulus were the main reasons for the formation of the above characteristics. Under the same of the number of fluid channels and Reynolds number, the average flow velocity, maximum velocity and flow contribution rate of the annular increased with depth, however, the situation of flow was opposite. In addition, the flow rate, flow and contribution rate of woody plant soil in each layer were higher than those of herb plant soil.
引文
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[20]路广遥,孙中宁,王经,等.窄缝环形通道内流动阻力特性的实验研究[J].核动力工程,2006,27(3):28–31
[21]幸奠川,阎昌琪,王畅,等.矩形通道高宽比对单相层流特性的影响[J].力学学报,2013,45(3):331–336
[2]Corominas J,Moya J.A review of assessing land slide frequency for hazard zoning purposes[J].Engineering Geology,2008,102(3):193–213
[3]Jakob M,Lambert S.Climate change effects on landslides along the southwest coast of British Columbia[J].Geomorphology,2009,107(3):275–284
[4]张友谊,胡卸文,朱海勇.滑坡与降雨关系研究展望[J].自然灾害学报,2007,16(1):104–108
[5]高华喜,殷坤龙.降雨与滑坡灾害相关性分析及预警预报阀值之探讨[J].岩土力学,2007,28(5):1055–1060
[6]张玉,徐卫亚,邹丽芳,等.降雨条件下大型滑坡体渗流稳定性分析[J].岩土力学,2013,34(3):833–841
[7]徐则民.植被与斜坡非饱和带大空隙[J].地学前缘,2007,14(6):134–142
[8]张家明,徐则民,裴银鸽.植被发育斜坡非饱和带大孔隙[J].山地学报,2012,30(4):439–449
[9]周赛,梁玉婷,孙波.红壤微生物群落结构及其演变影响因素的研究进展[J].土壤,2015,47(2):272–277
[10]李从娟,唐俊姸,高培,等.咸水灌溉对沙漠防护林植物根系分布及风沙土演变的影响[J].土壤学报,2015,52(5):1180–1187
[11]周赛,梁玉婷,张厚喜,等.我国中亚热带毛竹林土壤微生物群落的空间分布特征及其影响因素[J].土壤,2015,47(2):369–377
[12]李宗超,胡霞.小叶锦鸡儿灌丛化对退化沙质草地土壤孔隙特征的影响[J].土壤学报,2015,52(1):242–248
[13]盛丰,张利勇,王康.土壤大孔隙发育特征对水和溶质输移的影响[J].土壤,2015,47(5):1007–1013
[14]刘伟,区自清,应佩峰.土壤大孔隙及其研究方法[J].应用生态学报,2001,12(3):465–468
[15]王帮团,徐则民,王帮圆.植被发育斜坡土体中根–土间隙的导流特性[J].山地学报,2015,33(3):257–267
[16]Beven K,Germann P.Macropores and water flow in soils[J].Water Resources Research,1982,18(5):1311–1325
[17]高朝侠,徐学选,赵娇娜,等.土壤大孔隙流研究现状与发展趋势[J].生态学报,2014,34(11):2801–2811
[18]Hillel D.Introduction to soil physics[M].London:Academic Press,1982
[19]孙中宁,孙立成,阎昌琪,等.窄缝环形流道单相摩擦阻力特性实验研究[J].核动力工程,2004,25(2):123–127
[20]路广遥,孙中宁,王经,等.窄缝环形通道内流动阻力特性的实验研究[J].核动力工程,2006,27(3):28–31
[21]幸奠川,阎昌琪,王畅,等.矩形通道高宽比对单相层流特性的影响[J].力学学报,2013,45(3):331–336