中文摘要：

以青藏铁路沱沱河段路基边坡作为试验区,且在试验区路基边坡两侧种植了乡土护坡草本植物垂穗披碱草,通过对种植在试验区路基阴坡、阳坡生长5年的垂穗披碱草,做了野外原位根系拉拔试验,获得了垂穗披碱草根系抗拔力。研究表明：种植在阳坡的垂穗披碱草根系抗拔力为30.88N,阴坡抗拔力为23.52N,即种植在阳坡的垂穗披碱草根系抗拔力显著大于阴坡,影响其抗拔力大小的主要因素与土壤含水量及其变化有密切关系,试验区阳坡接受光照时间、程度均强于阴坡,试验区阳坡坡面土壤水分蒸发量大于阴坡这种差异形成阴坡、阳坡坡体土壤含水量不同的主要原因;垂穗披碱草根系抗拔力大小与须根数量、根径、根长、株高、根表面积、分蘖数之间均呈线性关系,其中抗拔力与须根数量之间呈显著性线性相关,阳坡垂穗披碱草抗拔力随根系数量增加的幅度显著大于阴坡,即当须根数量为40～60条时,阳坡垂穗披碱草的抗拔力集中分布在11～25N,阴坡抗拔力分布在8～15N;当须根数量为60～140条时,阳坡垂穗披碱草的抗拔力分布在30～70N,阴坡抗拔力为20～50N。根据路基边坡阴坡、阳坡垂穗披碱草根系抗拔力试验结果,评价了阴、阳两种坡向条件下垂穗披碱草根系护坡力学贡献,这对青藏铁路路基边坡种植草本植物实现该边坡与周边自然生态环境之间的协调发展具有理论指导意义。

英文摘要：

The Tuotuohe river region roadbed slopes lying along the Qinghai-Tibet railway were taken as the testing area, and Elymus nutans was planted at both sides of the slopes. The pull-out resistance was obtained by the in situ pull-out test in the testing area where five-year growth period Elymus nutans was planted at both the shading and the solar roadbed slopes, and the pull-out resistance value was obtained. The pull-out resistance value for solar roadbed slope is 30.88 N and 23.52 N for shading roadbed slopes, which shows that the soil moisture is the key factor affecting the roots＇ pull-out resistance. The longer shining time, the stronger intensity, and the larger evaporating amount of the solar slope contribute greatly to the different soil moisture in the solar and shading slopes. There exists a linear relationship between the pull-out resistance and the fibrous roots quantity, the roots diameter, the roots length, the above-ground biomass tall, the number of tillering and the roots surface area. The higher increasing amplitude exists between the pull-resistance and the fibrous roots quantity in the solar roadbed slope, which is obviously larger than that in the shading roadbed slope. When the number of fibrous roots ranges from 40 to 60, the roots pull-out resistance value of solar roadbed slope is between 11 N and 25 N, the roots pull-out resistance value of the shading roadbed slope ranges from 8 N to 15 N ; when the number of fibrous roots ranges from 60 to 140, the roots pull-out resistance value of solar roadbed slope is between 30 N and 70 N, and the roots pull-out resistance value of shading roadbed slope is between 20 N and 50 N. According to the roots mechanical strength of Elymus nutans, the mechanical contribution for slopes stability of Elymus nutans planted at the solar roadbed slope is relatively greater than that in the shading roadbed slope. The achievements can provide a theoretical guide for the research region and areas with the same ecological and geological environments for sowing herb