中文摘要：

以内蒙古鄂尔多斯地区低液限粉土和粉土质砂及其人工柠条林为研究对象，通过重塑土直剪试验研究土壤含水率对柠条根与两类土界面摩擦特性的影响，为根-土相互作用机理提供理论和数据支持。结果显示：随着土壤饱和度由25％增至85％，低液限粉土根-土界面的摩擦系数由0．438逐渐减小到0．35，粉土质砂则由0．517减至0．424；2种土壤质地根-土界面粘聚力呈先增大后减小的趋势，低液限粉土和粉土质砂根-土界面粘聚力分别在土壤饱和度为55％和40％时达到最大值，分别为4．986和3．056；土壤饱和度对根-土界面抗剪强度的影响随土壤类型的不同存在差异，在柠条根系主要分布层0．7m和1．4m内，2种土壤质地根-土界面抗剪强度随土壤饱和度增加呈现先增大后减小的趋势，且低液限粉土根-土界面抗剪强度高于粉土质砂，从固土效果角度，低液限粉土种植柠条的固土作用优于粉土质砂。

英文摘要：

Taking low liquid limit silt, silt sand and Caragana korshinskii plantation in Ordos area as research ob- jects, the influence of soil moisture content on interfacial friction of two types of soil and root of Caragana korshin- skii has been studied through shear test of remolded soil, which has provided the theoretical and data support for the root- soil interaction mechanism. The results show that with the increasing of the soil saturation from 25% to 85%, the root - soil interfacial friction coefficient of low liquid limit silt has decreased from 0. 438 to 0.35, the one of silt sand has decreased from 0. 517 to 0. 424. The root - soil interface cohesion of two types of soil has first in- creased and then decreased. When the soil saturation is 55% and 40% separately, the root -soil interface cohe- sion of low liquid limit soil and silt sand can reach the maximum vale, which is 4. 986 and 3.056 separately. The effect of soil saturation on the shear strength of root - soil interface varies with soil types. At 0. 7 m and 1.4 m in the main distribution layer of root system of Caragana korshinskii, the shear strength of two kinds of root - soil inter- face has first increased and then decreased with the increase of soil saturation, and the shear strength of root - soil interface of low liquid limit silt is higher than that of silt sand. The reinforcing effect of planting Caragana korshin- skii in low liquid limit silt is better than that in silt sand.