Abstract: In this study,a terrain occurred the thaw slumping disaster in the alpine meadow along Wudaoliang-Tuotuohe section in Qinghai-Tibet Highway was chosen as the test area. In order to quantitatively analyze the contribution of plant roots to the reinforcement of soil against thaw slumping and the stability improvement of shallow slope,tensile tests to a single root and cluster roots,and cracking tests to rooted soil,tensile resistance of a single root and cluster roots were investigated to evaluate the contribution of plant roots to enhancing soil strength and shallow slope stability in thaw slump region. And the following conclusions have been obtained:tensile resistance of single root increased with its diameter following a power law,and the tensile resistance of cluster roots increased with the increasing of number of roots,and the variation of resistance tensile with cluster roots can be described using linear equation. The in-situ tensile values of the meadow soil layer were generally smaller than the theoretical values. And the results above reflected the effect of roots on increase of soil strength and it was closely correlated with root diameter,root content in soil and soil compact. The results of this study would provide a theoretical support and practical guidance for the effective prevention and treatment of geological disasters such as thaw slumping and soil erosion of alpine meadow along the Qinghai-Tibet Highway.

Key words: Qinghai-Tibet highway, Alpine meadow, Thaw slump, Root tensile strength, Effect of cluster roots

摘要： 本项研究以青藏公路五道梁-沱沱河段一处发育的高寒草甸热融滑塌灾害作为研究对象,采用野外原位测量与室内单根、群根抗拉试验以及草甸层原位拉裂试验,研究了区内草本植物单根和群根力学性能及其特征,进一步评价了植物根系增强高寒环境热融滑塌区土体抗拉强度和提高边坡浅层稳定性贡献。结果表明:草本单根抗拉力及单根抗拉强度与根径间均呈幂函数关系;草本植物根数与群根抗拉力及群根抗拉强度之间均符合线性函数关系;草甸层原位抗拉试验值总体小于理论计算值。区内草本根系显著增强土体抗拉强度,且其增强土体强度贡献与根径、含根量和土壤密实度之间表现出显著相关性。本研究结果为有效防治青藏公路沿线高寒草甸热融滑塌、水土流失等地质灾害,起到提供理论支撑和实际指导作用。

关键词: 青藏公路, 高寒草甸, 热融滑塌, 根系抗拉强度, 群根效应