【作者】 倪三川；

【导师】 胡夏嵩； 毛小青；

【作者基本信息】 青海大学 ， 草业科学， 2008， 硕士

【摘要】 降雨入渗是非饱和土坡面失稳的主要诱发因素之一，滑坡与降雨有着密切的关系。本项研究通过室内模拟降雨试验，分别研究了披碱草坡面和柠条锦鸡儿坡面的产流、下渗、产沙规律，并与裸地坡面的产流、下渗、产沙规律进行了对比，得出如下结论：利用Green-Ampt模型模拟计算了降雨后侵润锋的位置，并与试验数据进行对比，草本、灌木坡面侵润锋较裸地坡面位置低，而柠条锦鸡儿坡面侵润锋位置最低，说明植物可以使更多的雨水下渗，从而也表明植被的保水作用。植被能有效的减少产流时间，削减产流量，在产流时间、产流量、径流转化率方面均表现为裸地坡面最大，柠条锦鸡儿坡面最小。在相同降雨强度、降雨历时条件下产流前的雨量损失，柠条锦鸡儿坡面最大，裸地坡面最小，说明了柠条锦鸡儿对降雨截留作用最明显。回归分析表明，裸地坡面降雨初损时间与降雨强度呈幂函数关系，披碱草坡面降雨初损时间与降雨强度呈现对数关系，柠条锦鸡儿坡面降雨初损时间与降雨强度亦呈对数关系，裸地坡面由于与种植披碱草及柠条锦鸡儿的坡面产流条件不同，降雨初损时间与降雨强度的回归关系也就不相同，这反映出裸地坡面和种植草本与灌木坡面产流规律不尽相同。通过对不同生长期草本及灌木坡面的对比分析得出：随着草本及灌木生长期的增加，径流转化率逐渐增大，而且披碱草坡面增加的幅度大于柠条锦鸡儿坡面，在生长期初期两者差异较小；随着草本及灌木生长期的增加，植物坡面下渗率逐渐减小，同一生长期披碱草坡面下渗率小于柠条锦鸡儿坡面，并且随着草本及灌木生长期的增加，披碱草坡面较柠条锦鸡儿坡面下渗率减小的速率快；另外，披碱草对地表径流的抑制作用大于柠条锦鸡儿，随着生长期的增加草本、灌木抑制地表径流的作用不断增大；草本、灌木坡面产沙量随着草本、灌木生长期的增加不断减小。试验过程中三种试验土槽装置所处环境相同，通过对降雨前土壤初始含水量的测量，测得披碱草坡面土壤初始含水量最小，裸地坡面土壤初始含水量最大，所以得出披碱草坡面蒸发量最大而裸地坡面蒸发量最小的结论。试验模拟降雨过程中对坡面产沙量的测量结果表明，种植披碱草坡面产沙量最小，柠条锦鸡儿坡面次之，裸地坡面最大，试验数据反映了裸地坡面的产沙量可以达到披碱草坡面的12.5倍。回归分析表明，坡面产沙强度与坡面承雨强度之间的关系符合线性关系，坡面产沙强度随着坡面承雨强度的增加而增加。更多还原

【Abstract】 Rainfall infiltration is one of main factors inducing slope instability. There isclose relation between sliding slope and rainfall. This paper studied the principle ofrunoff, infiltration, soil loss of slope growing Elymus dehuricus and Caraganakorshinskii through simulation rainfall in lab and compared with the principle of bareslope. Main conclusions are as follows:The location of erosion peak after rainfall is calculated by Green-Ampt modeland compared with experiment data. The erosion peak of slope growing grass andshrub is lower than those of bare slope. The lowest is the slope with Caraganakorshinskii, this indicates that plants make much water infiltration and vegetation hasanti-infiltration effect.Vegetation can decrease the time of runoff and runoff volume. Bare slope hasoptimum in time of runoff, runoff volume and runoff transferring rate. Slope growingCaragana korshinskii has the minimum. But under same rainfall intensity and samerainfall period, slope growing Caragana korshinskii has optimum, bare slope hasminimum. It shows that Caragana korshinskii is most effective in preventing rainfall.Regress analyzing shows that there is power function relation between initial losingtime of rainfall and rainfall intensity for bare slope; there is logistic relation forElymus dehuricus and for Caragana korshinskii. There exist different runoffconditions for bare slope and slope growing Elymus dehuricus and Caraganakorshinskii, so there is different regress relation of initial losing time of rainfall andrainfall intensity. This reflects different runoff principles for bare slope and slope withgrass and shrub.Conclusions are got through comparing grass slope with shrub slope in differentgrowing periods. Runoff transferring rate increases with period increasing, but Elymusdehuricus is faster than Caragana korshinskii. There was only a smaller differencebetween Elymus dehuricus and Caragana korshinskii at the initial growing period, butwith the growing period increasing and the gradual rainfall infiltration rate ofvegetation slope decreasing, the rainfall rate of Elymus dehuricus becomes smaller than that of Caragana korshinskii. Restraining runoff role for Elymus dehuricus isgreater than that of Caragana korshinskii. With growing period prolonging, such roleintense, but restraining slope sands increasing.Soil installment equipment of three kinds of experiments locate in sameenvironment. Measuring initial water content of soil before raining. The result thatwater content is minimum for Elymus dehuricus and Optimum water content is bareslope is got by measuring initial water content of soil before raining. The conclusionis: transpiration volume is optimum for Elymus dehuricus; Minimum is for bare slope.By measuring soil loss volume of slope with simulation rainfall experiment, theauthor got the following results: slope growing Elymus dehuricus has minimum soilloss volume; lope growing Caragana korshinskii stands second; bare slope hasgreatest soil loss volume. Experiment data indicates that soil loss volume is12.5timesfor bare slope than those of Elymus dehuricus. Regress analyzing showed that there islinear relationship between soil loss volume intensity and bearing raining intensity,soil loss volume intensity increase with bearing raining intensity increasing.更多还原