本文選題：侵蝕 + 徑流��； 參考：《農(nóng)業(yè)工程學(xué)報(bào)》2017年08期

【摘要】：為分析近地表水文條件影響下WEPP(Water Erosion Prediction Project)模型估計(jì)細(xì)溝可蝕性和臨界剪切力的可行性,該研究選取長(zhǎng)江中上游地區(qū)典型黃壤為研究對(duì)象,采用不同水力梯度值模擬飽和/滲流(水力梯度為0、0.71和1.43 m/m)和排水(水力梯度為?0.71和?1.43 m/m)2種近地表水文條件,并設(shè)置3個(gè)放水流量(0.55、1.58、2.51 L/min),利用"V"形試驗(yàn)土槽測(cè)定不同條件下細(xì)溝產(chǎn)流產(chǎn)沙,以WEPP模型估算的土壤可蝕性和臨界剪切力為計(jì)算值。測(cè)定增大流量直到侵蝕開(kāi)始并出現(xiàn)連續(xù)不斷的土壤顆粒分離時(shí)所對(duì)應(yīng)的流量,將基于此流量計(jì)算獲得的臨界剪切力作為實(shí)測(cè)值。比較臨界剪切力計(jì)算值與實(shí)測(cè)值驗(yàn)證WEPP模型估算的可靠性。結(jié)果表明,在飽和/滲流條件下,土壤剝蝕率隨著沖刷歷時(shí)的增加逐漸減小;在排水條件下,放水流量為0.55 L/min的土壤剝蝕率隨沖刷歷時(shí)的增加快速減少并逐步穩(wěn)定,而隨著放水流量增大土壤剝蝕率波動(dòng)的更為劇烈。5個(gè)水力梯度平均細(xì)溝可蝕性為2.51×10?2 s/m。飽和/滲流條件下細(xì)溝可蝕性為3.07×10?2 s/m,是排水條件的1.78倍。除水力梯度為?1.43 m/m時(shí)臨界剪切力在WEPP模型中的計(jì)算值與實(shí)測(cè)值相符外,在?0.71~1.43 m/m范圍內(nèi),臨界剪切力的計(jì)算值均高估了實(shí)測(cè)值,平均高估了36.85%。臨界剪切力實(shí)測(cè)值與計(jì)算值呈指數(shù)函數(shù)關(guān)系(R2=0.77,P0.01)。該研究可為黃壤的侵蝕防治及WEPP細(xì)溝侵蝕模型臨界剪切力修正提供理論支持和科學(xué)指導(dǎo)。
[Abstract]:In order to analyze the feasibility of estimating the erodibility and critical shear stress of rill by WEPP (Water erosion Prediction Project) model under the influence of near-surface hydrological conditions, the typical yellow soil in the upper and middle reaches of the Yangtze River was selected as the research object. Two kinds of near-surface hydrological conditions are simulated by using different hydraulic gradient values (hydraulic gradient 0 0. 71 and 1. 43 m / m) and drainage (hydraulic gradient 0. 71 and 1. 43 m / m). At the same time, three water discharge rates (0.555 ~ 1.58 ~ 2.51 L / min) were used to measure sediment yield under different conditions. The soil erodibility and critical shear force estimated by WEPP model were calculated. The critical shear force calculated on the basis of the increasing flow rate until the erosion begins and the continuous soil particle separation occurs is taken as the measured value. The reliability of the WEPP model is verified by comparing the critical shear force calculation values with the measured values. The results showed that the soil erosion rate decreased gradually with the increase of erosion duration under saturated / percolation condition, and decreased rapidly with the increase of erosion duration when the discharge rate was 0.55 L / min. The erosion rate fluctuated more sharply with the increase of water discharge. The erodibility of the five hydraulic gradients was 2.51 脳 10 ~ (2) s / m. The erodibility of the rill under saturated / percolation is 3.07 脳 10 ~ (2) s / m, which is 1.78 times as much as the drainage condition. Except when the hydraulic gradient is 1.43 m / m, the calculated value of critical shear force in WEPP model is in agreement with the measured value. In the range of 0.71 ~ 1.43 m / m, the calculated value of critical shear force overestimates the measured value and the average value is 36.85%. The experimental value of critical shear force is exponentially related to the calculated value (R2 / 0.77 / P0.01). This study can provide theoretical support and scientific guidance for erosion control of yellow soil and revision of critical shear force of WEPP rill erosion model.
【作者單位】： 北京林業(yè)大學(xué)水土保持學(xué)院;北京林業(yè)大學(xué)重慶縉云山三峽庫(kù)區(qū)森林生態(tài)系統(tǒng)國(guó)家定位觀測(cè)研究站;
【基金】：北京高等學(xué)校青年英才計(jì)劃資助(YETP0751) 國(guó)家自然科學(xué)基金項(xiàng)目(41401299)
【分類號(hào)】：S157.1
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本文編號(hào)：2081145