农业工程学报
農業工程學報
농업공정학보
2014年
20期
118-127
,共10页
吴庆华%朱国胜%崔皓东%张家发%张发旺
吳慶華%硃國勝%崔皓東%張傢髮%張髮旺
오경화%주국성%최호동%장가발%장발왕
土壤%水%孔隙结构%优先通道%优先流%降雨强度%双渗透模型%Hydrus-1D
土壤%水%孔隙結構%優先通道%優先流%降雨彊度%雙滲透模型%Hydrus-1D
토양%수%공극결구%우선통도%우선류%강우강도%쌍삼투모형%Hydrus-1D
soils%water%pore structure%preferential path%preferential flow%precipitation intensity%dual-permeability model%Hydrus-1D
为了研究优先通道发育程度对不同降雨强度下优先流特征的影响，该文选取不同深度的田间原状土样，在不同降雨强度下进行土壤优先流的室内物理模拟试验，并采用双渗透介质模型Hydrus-1D对优先流发育过程进行数值模拟。结果表明：优先通道越发育，其优先流程度越高。降雨强度对优先流速率及其增加幅度的影响随土壤优先通道发育程度的增加而增加。优先通道发育的土柱，降雨强度越大时，其土柱下端初始出流时间越短，而优先通道一般发育的土柱，其土柱下端初始出流时间均随降雨强度增加呈先减小而后增加的规律。当降雨强度小于土柱最大导水能力（原状土柱表面出现积水时的导水能力）时，优先流速率随降雨强度增加而显著增加，而当降雨强度接近或大于其最大优先导水能力时，优先流速率增加缓慢或趋于稳定。土壤优先通道对降雨入渗的导水能力（即优先流速率与降雨强度之比）随降雨强度增加而变小。双渗透介质模型能较理想地模拟优先流发育过程，对土壤基质向大孔隙排水过程的模拟较差，但模型不适用于裂隙发育的土壤。各土柱的优先流程度为93.6%～99.9%。在研究降雨强度对优先流的影响规律时，该研究考虑了优先通道发育程度对此规律的影响，丰富了优先流理论，同时对农业节水、土壤污染迁移、地下水污染风险评价以及滑坡机理等研究方面具有重要的科学意义。
為瞭研究優先通道髮育程度對不同降雨彊度下優先流特徵的影響，該文選取不同深度的田間原狀土樣，在不同降雨彊度下進行土壤優先流的室內物理模擬試驗，併採用雙滲透介質模型Hydrus-1D對優先流髮育過程進行數值模擬。結果錶明：優先通道越髮育，其優先流程度越高。降雨彊度對優先流速率及其增加幅度的影響隨土壤優先通道髮育程度的增加而增加。優先通道髮育的土柱，降雨彊度越大時，其土柱下耑初始齣流時間越短，而優先通道一般髮育的土柱，其土柱下耑初始齣流時間均隨降雨彊度增加呈先減小而後增加的規律。噹降雨彊度小于土柱最大導水能力（原狀土柱錶麵齣現積水時的導水能力）時，優先流速率隨降雨彊度增加而顯著增加，而噹降雨彊度接近或大于其最大優先導水能力時，優先流速率增加緩慢或趨于穩定。土壤優先通道對降雨入滲的導水能力（即優先流速率與降雨彊度之比）隨降雨彊度增加而變小。雙滲透介質模型能較理想地模擬優先流髮育過程，對土壤基質嚮大孔隙排水過程的模擬較差，但模型不適用于裂隙髮育的土壤。各土柱的優先流程度為93.6%～99.9%。在研究降雨彊度對優先流的影響規律時，該研究攷慮瞭優先通道髮育程度對此規律的影響，豐富瞭優先流理論，同時對農業節水、土壤汙染遷移、地下水汙染風險評價以及滑坡機理等研究方麵具有重要的科學意義。
위료연구우선통도발육정도대불동강우강도하우선류특정적영향，해문선취불동심도적전간원상토양，재불동강우강도하진행토양우선류적실내물리모의시험，병채용쌍삼투개질모형Hydrus-1D대우선류발육과정진행수치모의。결과표명：우선통도월발육，기우선류정도월고。강우강도대우선류속솔급기증가폭도적영향수토양우선통도발육정도적증가이증가。우선통도발육적토주，강우강도월대시，기토주하단초시출류시간월단，이우선통도일반발육적토주，기토주하단초시출류시간균수강우강도증가정선감소이후증가적규률。당강우강도소우토주최대도수능력（원상토주표면출현적수시적도수능력）시，우선류속솔수강우강도증가이현저증가，이당강우강도접근혹대우기최대우선도수능력시，우선류속솔증가완만혹추우은정。토양우선통도대강우입삼적도수능력（즉우선류속솔여강우강도지비）수강우강도증가이변소。쌍삼투개질모형능교이상지모의우선류발육과정，대토양기질향대공극배수과정적모의교차，단모형불괄용우렬극발육적토양。각토주적우선류정도위93.6%～99.9%。재연구강우강도대우선류적영향규률시，해연구고필료우선통도발육정도대차규률적영향，봉부료우선류이론，동시대농업절수、토양오염천이、지하수오염풍험평개이급활파궤리등연구방면구유중요적과학의의。
The preferential flow is common in the soil with preferential paths, which affects soil water infiltration greatly. Although previous studies have made a great progress in preferential flow, the effect of preferential paths on preferential flow has not been reported, and a great effort is necessary to understand how precipitation intensities affect preferential flow. Therefore, in this paper, five undisturbed soil columns were sampled at the depth of 0-100 cm with different distribution of preferential paths from the Experimental Station of the Institute of Hydrogeology and Environmental Engineer, Chinese Academy of Geological Science (Hebei, China) and from Luancheng Experimental Station of Chinese Academy of Science (Hebei, China). Tests of different precipitation intensities, i.e., 0.23-0.24, 0.07-0.11, and 0.008-0.042 cm/min, were done to investigate preferential flow of the five soil columns. And the Hydrus-1D software coupling a dual-permeability model was applied to simulate the preferential flow of the soil columns under differential rainfall intensities. The results showed that the preferential paths played a vital role in development of the preferential flow since the levels of preferential flow were higher with more preferential paths in the soils. The relative transport abilities of preferential paths, which were defined by the ratio of velocity of preferential flow to rainfall intensity, increased with heavier rainfall. When the rainfall intensities were larger than the maximal coefficients of hydraulic conductivity of the intact soil columns, the velocities of preferential flow increased remarkably with increase of rainfall intensities. However, when the rainfall intensities were smaller than the maximal coefficients of hydraulic conductivity, the velocities of preferential flow increased little or no change. The effect of rainfall intensities on theνand increased ranges ofνwas related to the development of preferential paths in the intact soil columns, i.e., the effect can be stronger with the higher degree of preferential paths. In the soil columns with better development of preferential paths, the initial times of soil water flowing out at the bottom of the soil columns were shorter when rainfall intensities were larger, while in the soil columns with well developed preferential paths, the initial times of soil water flowing out at the bottom of the soil columns decreased firstly with a higher rainfall intensity, and then increased. The dual-permeability model described preferential flow well but couldn’t simulate the process that soil water in the soil matrix flowed out horizontally to preferential paths after the rainfalls. As such the model was not suitable for the soils with plenty of soil fissures. The percentage of preferential flow obtained from the results of modeling was 93.6%-99.9%, which was in agreement with the tested results in undisturbed to disturbed soil. It suggested the model could simulate the preferential flow well. However, the results may be affected by size of columns since the characteristics of preferential flow varied with study scales. Therefore, further studies were needed to improve the understanding of preferential flow in larger scales. The results here will be useful to evaluate the groundwater recharge, water saving methods and movement of soil pollutants in arable land.
