Study on tensile properties of root-soil composite of alpine meadow plants in the riparian zone of the Yellow River source region
LI Benfeng1，ZHU Haili1，2，XIE Binshan1，LUO Luyao1，LI Guorong1，2，HU Xiasong1
(1. Department of Geological Engineering，Qinghai University，Xining，Qinghai 810016，China；2. Key Laboratory of Cenozoic Resource and Environment in North Margin of the Tibetan Plateau，Qinghai University，Xining，Qinghai 810016，China)
Abstract：As a special material of bank soil composition，riparian plant roots play an important role in adjusting mechanical properties of soils. In-situ tensile tests of two types of vegetation community root-soil composites were carried out by the hollowing method at three sites at the river bank of the source region of the Yellow River covered by alpine meadow，and the reinforcement effect of the root system of meadow vegetation on the tensile strength of soils of the river bank was analyzed. The collapse width of the meadow-covered bank is 0.52–0.70 m and obviously larger than that of the cohesive soil bank，and the collapse width of the native meadow bank is higher than that of the moderately degraded meadow bank. The average single root tensile strength of Blysmus sinocompressus，a dominant species of native alpine meadow，is 31.67 MPa，which is 15.52 MPa higher than that of the moderately degraded meadow dominant species Elymus nutans. The root area ratio of the former is about 2–3 times higher than that of the later. It is shown that the root system of riparian meadow has an inhibition effect on bank collapse process. The tensile strengths of vegetation root-soil composites in the three sites calculated by the critical equilibrium formula of bank collapse are 66.86，21.29 and 22.63 kPa，respectively. It is also indicated that the tensile strength of a single root and the root area ratio have a positive effect on enhancing the tensile strength of the soil-root composite. The tensile strength of the soil-root composite obtained by the critical equilibrium formula is in good agreement with that by Wu-Waldron root system model with a correction coefficient and the relative error is between 2.12%–9.21%. This test method is of importance to the in-situ measurement of the soil-root composite at riparian banks and provides field data for the theoretical study on bank collapse mechanisms in this region.
李本锋1，朱海丽1，2，谢彬山1，罗露瑶1，李国荣1，2，胡夏嵩1. 黄河源区河岸带高寒草甸植物根–土复合体抗拉特性研究[J]. 岩石力学与工程学报, 2020, 39(2): 424-432.
LI Benfeng1，ZHU Haili1，2，XIE Binshan1，LUO Luyao1，LI Guorong1，2，HU Xiasong1. Study on tensile properties of root-soil composite of alpine meadow plants in the riparian zone of the Yellow River source region. , 2020, 39(2): 424-432.
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2020, Vol. 39 
