中文摘要：

为研究盐生植物根系的固土护坡力学效应,探讨土体粒径对植物根系加筋固土作用和提高土体抗剪强度的影响。以青海柴达木盆地大柴旦盐湖区为研究区,选取海韭菜（Triglochin maritima Linn.）和无脉苔草（Carex enervis C.A.Mey.）2种优势盐生植物作为供试种,选取粒径大小分别为颗粒直径d≤0.25 mm和d≤0.5 mm粒径条件下的2种土体,制备根–土复合体扰动试样和不含根系素土扰动试样,分别进行了不固结不排水三轴压缩试验,以探讨2种盐生植物增强土体抗剪强度贡献,以及2种粒径条件下的根–土复合体抗剪强度指标变化规律;在此基础上,探讨土体粒径差异对根–土复合体抗剪强度的影响。试验结果表明：盐生植物根系加筋固土作用主要表现为在2种不同土体粒径条件下,海韭菜根–土复合体与无脉苔草根–土复合体抗剪强度强度均显著大于素土抗剪强度,且垂直布根海韭菜根–土复合体的抗剪强度显著大于水平或倾斜布根无脉苔草根–土复合体抗剪强度;土体粒径的差异可影响植物根系增强土体抗剪强度大小,即主要表现为在相同的含根量条件下,土体粒径愈小,由该粒径土体与根系共同组成的根–土复合体黏聚力值则愈大。同时,进一步研究表明,水平或倾斜布根的无脉苔草根–土复合体的抗剪强度受土体粒径大小的影响,相对大于垂直布根的海韭菜根–土复合体中的土体粒径大小对其抗剪强度影响。研究成果对于进一步探讨盐生植物根–土复合体抗剪强度的影响因素,以及利用盐生植物有效防治研究区水土流失、土壤侵蚀等地质灾害方面具有重要理论指导意义。

英文摘要：

To study the mechanical effect of slope protection by halophytes and to investigate the influence of grain size on the shear strength of the rooted soil,Qaidam Basin in Qinghai province was selected as the test site and 2 halophytes（Triglochin maritima Linn. and Carex enervis C.A.Mey） were selected for study. To investigate the contribution of halophytes to the shear strength of the rooted soil and the variation of shear strengths,undrained-unconsolidation triaxial compression tests were conducted on the rooted soil and non-rooted soil samples with the grain size d≤0.25 mm and d≤0.5 mm prepared by sieving and remolding. The results showed that halophytes played significant roles in soil reinforcement. The shear strengths of rooted soil for T. maritima and C. enervis were notably larger than those of non-rooted soil and the shear strength of the vertically rooted soil was larger than that of horizontally rooted soil. The grain size influenced the shear strength of the soil. Under the same root content,the rooted soil with smaller grain size had larger value in cohesion force. The horizontally rooted soil of C. enervis was notably influenced by the grain size than the vertically rooted soil of T. maritima in shear strength of the soil.