【摘要】 沙打旺、紫花苜蓿和小叶锦鸡儿三种植物对土壤抗剪强度的增强值,随着穿过剪切平面的根断面积率(根截面积/剪切平面面积)的增高而增高,求得了三种植物对各层次土壤抗剪强度的增强伊与剪切平面上根截面积率的回归方程式。三种植物根系对土壤抗剪强度的增强作用,都表现出随深度的增加而减小的规律,但这种增强作用均超过了100厘米。三种植物地各层次根截面积率和对土壤抗剪强度的增强作用,以紫花苜蓿最大,影响深度也最大;小叶锦鸡儿虽然在一些层次的根截面积率比沙打旺小,但由于它的根的抗拉强度大于沙打旺,而使得它对土壤抗剪强度的增强作用比沙打旺大。这三种植物根系对土壤抗剪强度的增强作用最终导致了对斜坡稳定性的增强。假定当空闲地斜坡处于临界稳定状态时(稳定系数 K=1)、三种植物生长的斜坡各层次的稳定系数都大于1,表明三种植物在其根系分布层内都对斜坡的稳定性具有明显的增强作用。更多还原

【Abstract】 The increasing value of the three plants,Astragalus adsurgens Pall., Medicago sativa L.and Caragana microphylla Lam.,to the shear strength of soil,increase as the area ratio of roots(ratio of cross section area of roots to the area of shear plane) passing through shear plane increase.A regression model between the increasing value of shear strength and the area ratio of roots on shear plane at each layer of soil for the three plants is obtained.Each of the plants shows the rule that the effect of roots on the strengthening of shear strength of soil is decreased as it is deepened, but the effecting depth is over 100cm.On the area ratio of roots,in each layer and the effect on the strengthening of shear strength of soil of the plants,Medicago sativa is the most,which also effects the deepest.Al- though Caragana micropylla Lam.has a smaller area ratio of roots than Astragalus adsurgens Pall.in some layers,it has greater effect on the strengthening of shear strength of soil than the latter due to the great tensile strength. The strengthening effects of the roots of the three plants to the shear strength of soil result in the increasing of the slope stability.Pro- vided the slope in fallow is on the critical state of stability(stability coef- ficient k=1),k value at each layer of the slope grown in the plants is more than 1,which demonstrates that the three plants have a signifi- cant effect on the strengthening of the slope stability in the range where roots are distributed.更多还原