本文關(guān)鍵詞： 紫色土 覆蓋度 粒徑 水動(dòng)力學(xué)特性 細(xì)溝侵蝕　出處：《華中農(nóng)業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：紫色土是一種初育土,結(jié)構(gòu)疏松,母巖裂隙發(fā)育,極易風(fēng)化,土壤侵蝕十分強(qiáng)烈。由于紫色土風(fēng)化程度淺,礫石含量高成為了紫色土主要特征之一。坡面薄層水流是土壤水蝕過(guò)程的主要?jiǎng)恿?水動(dòng)力學(xué)特性與坡面侵蝕密切相關(guān),而礫石覆蓋和粒徑大小對(duì)坡面薄層水流水動(dòng)力學(xué)參數(shù)有著重要影響,開(kāi)展不同礫石覆蓋度和不同礫石粒徑大小對(duì)坡面流水動(dòng)力學(xué)參數(shù)變化的研究,不僅能夠深入認(rèn)識(shí)礫石對(duì)坡面侵蝕的作用機(jī)理及其影響,更重要的是能夠?yàn)樽仙恋貐^(qū)水土保持措施規(guī)劃以及水土流失治理方案提供科學(xué)依據(jù)。本試驗(yàn)以三峽庫(kù)區(qū)秭歸縣王家橋小流域的紫色土為研究對(duì)象,選用光滑的鵝卵石并設(shè)置了5種礫石覆蓋度(0、10%、20%、30%和40%),四種粒徑大小(0.5-1 cm、1-2 cm、2-4 cm和4-6 cm)以及三種沖刷流量(2 L/min、4 L/min和6 L/min),坡度設(shè)置為5度,通過(guò)室內(nèi)模擬沖刷實(shí)驗(yàn)(土槽2 m×0.5 m×0.15 m),對(duì)紫色土坡面流水動(dòng)力學(xué)特性及細(xì)溝侵蝕含沙量變化的主要研究結(jié)論如下:(1)隨著礫石覆蓋度的增大,流速和弗勞德數(shù)有減小的趨勢(shì);徑流深、水流剪切力、水流功率、阻力系數(shù)和曼寧糙率系數(shù)等都有增大的趨勢(shì),雷諾數(shù)變化不明顯;細(xì)溝內(nèi)雷諾數(shù)、平均流速、徑流深和水流剪切力要比細(xì)溝間大;細(xì)溝內(nèi)阻力系數(shù)和曼寧糙率系數(shù)一般要比細(xì)溝間小,特別是在覆蓋度較大的條件下差異更為顯著;隨著沖刷流量的增大,雷諾數(shù)、徑流深、水流剪切力等有增大的趨勢(shì)。(2)徑流含沙量隨著沖刷流量增大而增大,隨著礫石覆蓋度的增大而減小。不同礫石覆蓋度下徑流含沙量變化趨勢(shì)基本相同,在沖刷流量較大時(shí)(6 L/min)表現(xiàn)為先增大后減小,最后趨于平穩(wěn)的趨勢(shì);在沖刷流量較小時(shí)(2 L/min),徑流含沙量一直緩慢增大;細(xì)溝在無(wú)礫石覆蓋時(shí)比有礫石覆蓋發(fā)育快,在沖刷流量大時(shí)比沖刷流量小時(shí)發(fā)育快,徑流含沙量的變化與細(xì)溝形態(tài)發(fā)育以及水流剪切力密切相關(guān)。(3)隨著礫石粒徑的增大,阻力系數(shù)和曼寧糙率系數(shù)等有減小的趨勢(shì);流速、徑流深、水流剪切力、水流功率等有增大的趨勢(shì),雷諾數(shù)變化不明顯;細(xì)溝內(nèi)雷諾數(shù)、平均流速、徑流深和水流剪切力要比細(xì)溝間大;細(xì)溝內(nèi)阻力系數(shù)和曼寧糙率系數(shù)一般要比細(xì)溝間小;隨著沖刷流量的增大,雷諾數(shù)、徑流深、水流剪切力等有增大的趨勢(shì);相同沖刷流量下,隨著礫石粒徑的增大,侵蝕量不斷增大。
[Abstract]:Purple soil is a kind of initial fertility soil with loose structure, the fissures of parent rock develop easily weathering, and soil erosion is very strong. High gravel content has become one of the main characteristics of purple soil. Thin layer flow is the main driving force of soil erosion, and hydrodynamic characteristics are closely related to slope erosion. The gravel coverage and particle size have an important influence on the hydrodynamic parameters of thin layer water income on the slope surface. Not only can the action mechanism of gravel on slope erosion and its effect on slope erosion be deeply understood, More importantly, it can provide a scientific basis for the planning of soil and water conservation measures and soil erosion control schemes in purple soil areas. This experiment takes the purple soil in the Wangjiaqiao small watershed of Zigui County, three Gorges Reservoir area, as the research object. The smooth cobblestones were selected and five kinds of gravel coverage were set up, including 30% and 40%, four sizes of 0.5 ~ (-1) cm ~ (2) cm ~ (2) ~ (2) cm ~ (2) and 4 ~ (6) cm), and three kinds of scour flow rates of 2 L / min and 6 L / min, with a slope of 5 degrees. Through the indoor simulated scour experiment (soil trough 2 m 脳 0.5 m 脳 0.15 m), the main research on the dynamic characteristics of income on the purple soil slope and the change of sediment content of rill erosion are as follows: 1) with the increase of gravel coverage, the velocity of flow and the Froude number decrease; Runoff depth, flow shear force, flow power, resistance coefficient and Manning roughness coefficient are all increasing, Reynolds number is not obvious, Reynolds number, average velocity, runoff depth and flow shear force are larger than those between the gullies. The resistance coefficient and Manning roughness coefficient in the rill are generally smaller than those between the furrows, especially under the condition of large coverage, the Reynolds number and runoff depth increase with the increase of scour discharge. The runoff sediment content increases with the increase of scour discharge and decreases with the increase of gravel coverage. When the scour flow is larger, the runoff sediment content increases slowly when the scour flow is larger, then increases, then decreases, and finally tends to steady. When the scour flow is less than 2 L / min, the sediment content in the runoff increases slowly, and the sediment content in the rill develops faster than the gravel cover when the scour flow is small. With the increase of gravel particle size, the resistance coefficient and the Manning roughness coefficient decrease with the increase of gravelly particle size, and the velocity of flow, the change of runoff sediment content is closely related to the development of rill shape and flow shear force. Runoff depth, flow shear force, flow power and so on have an increasing tendency, Reynolds number is not obvious, Reynolds number, mean velocity, runoff depth and flow shear force are larger than those between gullies. The resistance coefficient and Manning roughness coefficient in the rill are generally smaller than those between the furrows; with the increase of scour flow, Reynolds number, runoff depth, flow shear force and so on, there is an increasing trend, and at the same scour flow rate, with the increase of gravel particle size, The amount of erosion is increasing.
【學(xué)位授予單位】：華中農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S157

【參考文獻(xiàn)】

相關(guān)期刊論文 前9條

1 符素華,段淑懷,劉寶元;密云石匣小流域土地利用對(duì)土壤粗化的影響[J];地理研究;2001年06期

2 符素華,劉寶元;土壤侵蝕量預(yù)報(bào)模型研究進(jìn)展[J];地球科學(xué)進(jìn)展;2002年01期

3 史立人;長(zhǎng)江流域水土流失特征、防治對(duì)策及實(shí)施成效[J];人民長(zhǎng)江;1998年01期

4 雷廷武,M.A.Nearing;侵蝕細(xì)溝水力學(xué)特性及細(xì)溝侵蝕與形態(tài)特征的試驗(yàn)研究[J];水利學(xué)報(bào);2000年11期

5 吳士佳;四川省水土流失分區(qū)和水土保持工作[J];水土保持通報(bào);1986年03期

6 符素華;路炳軍;葉芝菡;;地表礫石對(duì)降雨徑流及土壤侵蝕的影響[J];水土保持學(xué)報(bào);2010年02期

7 張科利,唐克麗;黃土坡面細(xì)溝侵蝕能力的水動(dòng)力學(xué)試驗(yàn)研究[J];土壤學(xué)報(bào);2000年01期

8 蘇濤;張興昌;趙懷玉;;砒砂巖地區(qū)坡面徑流水動(dòng)力學(xué)特性研究[J];西北農(nóng)林科技大學(xué)學(xué)報(bào)(自然科學(xué)版);2011年08期

9 姚文藝;坡面流流速計(jì)算的研究[J];中國(guó)水土保持;1993年03期

相關(guān)博士學(xué)位論文 前1條

1 王小燕;紫色土碎石分布及其對(duì)坡面土壤侵蝕的影響[D];華中農(nóng)業(yè)大學(xué);2012年

相關(guān)碩士學(xué)位論文 前1條

1 王龍生;黃土坡面細(xì)溝流水動(dòng)力學(xué)特性試驗(yàn)研究[D];華中農(nóng)業(yè)大學(xué);2014年

，

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