STRENGTH CHARACTERISTICS OF SINGLE ROOT TENSILE TEST OF HERBS AND SHRUBS IN COLD AND ARID ENVIRONMENTS

This paper is to further explore the mechanical effects of plants in slope protection in cold and arid environments. It selects five kinds of native herbs and shrubs as the test samples. They are suitable for the local climate conditions. They are planted in the self-built test area in this research. The single tensile tests are carried out to systematically analyze the strength characteristics of plant roots of the five kinds of herbs and shrubs. The results show the follows. The single root tensile resistances increases with the diameter increasing. Power relations exist between single root tensile resistances and root diameters of the herbs and shrubs respectively. Meanwhile, the single root tensile strengths increase with the diameter decreasing. Power relations exist between single root tensile strengths and root diameters of five kinds of herbs and shrubs respectively. The single root tensile strength of Elymus nutans Griseb is bigger than that of Agropyron trachycaulum(Linn.) Gaertn, while the sequence of the single tensile strengths of shrubs from big to small is Caragana korshinskii Kom,Zygophyllum xanthoxylon(Bunge) Maxim. and Nitraria tangutorum Bobr. Besides, some phenomena are shown by comparing and analyzing the stress-strain relationship curves of tensile tests of three kinds of shrubs in the vegetative period of 1a and 2a. That is,in the early single root tensile test of shrubs, there is a linear relationship between stress and strain, which shows the elastic material properties. Until the middle and late stage of the test, the relationship between stress and strain is nonlinear and shows the elastic-plastic material properties. Further research shows a downward trend of the largest elongation of the shrub single root with the increasing of vegetative period. The results of the study have a theoretical researching and practical guiding significance in the prevention and treatment of geological disasters such as shallow landslide and soil erosion in the study area and in the protection of the regional ecological geological environment.