【作者】 李宁；

【导师】 陈丽华；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2016， 硕士

【摘要】 植物根系的抗拉性能是影响边坡稳定性的重要因素。为探究植物根系的基本力学特性及其影响因素,本研究以华北地区常见的四种乔木油松、落叶松、白桦、蒙古栎为研究对象,通过单根室内拉伸试验以及根系主成分分析试验,研究了不同因素对4个树种根系抗拉特性的影响机制,并利用多元回归分析了它们之间的相关关系,旨在为根系固土提供数据支持。主要研究成果如下：(1)油松、落叶松、白桦、蒙古栎四个树种根系的最大抗拉力均与直径呈幂函数正相关关系,但抗拉强度与直径相关性不明显；在相同根径条件下,四个树种根系的最大抗拉力、抗拉强度,平均抗拉力、抗拉强度均表现为：白桦>蒙古栎>油松>落叶松；在相同标距条件下,四个树种根系最大抗拉力、抗拉强度与拉伸速率的关系均表现为：200mm/min<100mm/min<10mm/min;在相同拉伸速率条件下,四个树种根系最大抗拉力、抗拉强度与标距的关系均表现为：200mm<150mm<100mm<50mm。(2)直径是影响根系最大抗拉力的最主要因素,其次是树种,再次是标距,拉伸速率影响最小；树种是影响根系抗拉强度的最主要因素,其次是标距,拉伸速率影响最小。根系最大抗拉力与直径正相关,最大抗拉力和抗拉强度均与标距和拉伸速率负相关。(3)对于油松和落叶松,根系含水量对最大抗拉力、抗拉强度影响显著；径级为1-6时,根系含水量级与最大抗拉力、抗拉强度呈负相关关系；根系含水量对平均抗拉力、平均抗拉强度影响显著,随含水量级的增大,根系平均抗拉力、抗拉强度出现先增加后降低的规律,基本上油松根系在含水量为37%-45%时,落叶松根系含水量为20.4%～28.05%1时,两个树种的抗拉性能最优。(4)纤维素、半纤维素、综纤维素含量与油松、落叶松根系直径、最大抗拉力均显著正相关,与根系抗拉强度相关性不明显；与白桦、蒙古栎根系直径、最大抗拉力显著负相关,与根系抗拉强度显著正相关。木质素含量、木纤比与油松、落叶松根系直径、最大抗拉力显著负相关,与根系抗拉强度相关性不明显；与白桦、蒙古栎根系直径、最大抗拉力显著正相关,与抗拉强度显著负相关。(5)油松和落叶松根系最大抗拉力与直径、木纤比、综纤维素含量显著正相关,抗拉强度与根系主要化学成分均没有明显相关关系。白桦和蒙古栎根系最大抗拉力与直径、木纤比显著正相关,与木质素显著负相关,抗拉强度仅与综纤维素显著正相关。更多还原

【Abstract】 Root tensile properties of vegetation are very important to slope stability. To explore the basic properties of plant roots and influencing factors, we selected Pinus tabuliformis, Larix principis-rupprechtii, Betula platyphylla, Quercus mongolica as our experimental species, through root tensile test indoors and principal component analysis test, we studied effect mechanism of different factors on four species root, multiple regression was used to investigate the relationship between root tensile properties and the influencing factors. The main results of this article are as follows:(1) Root diameter had a significantly positive correlation with root tensile resistance of four species and their relation accorded with the power function, but no correlation could be observed between tensile strength and root diameter. The root tensile resistance and tensile strength, average root tensile resistance and tensile strength of the four species at the same root diameter descended as Betula platyphylla> Quercus mongolica> Pinus tabuliformis> Larix principis-rupprechtii; The root tensile resistance and tensile strength of the four species at different tensile rates descended as 200 mm/min< 100 mm/min< 10 mm/min; The root tensile resistance and tensile strength of the four species at different gauge lengths followed a descending order as 200 mm< 150 mm< 100 mm< 50 mm.(2)The root diameter was the main factor affecting the tensile resistance, followed by the species, again the gauge length, the minimum was tensile rate; Species was the main factor affecting the tensile strength, followed by the gauge length, the minimum was tensile rate. Root diameter had a significantly positive correlation with root tensile resistance, the gauge length and tensile rate had a significantly negative correlation with root tensile resistance and tensile strength.(3) Root moisture content had a significant impact on root tensile resistance and tensile strength of Pinus tabuliformis and Larix principis-rupprechtii; Root moisture content had a significantly negative correlations with root tensile resistance and tensile strength under diameter class 1-6; Root moisture content had a significant impact on root mean tensile resistance and tensile strength, the root mean tensile resistance and tensile strength increased in the first after the law with the decrease in diameter, basically the root tensile properties of two species were best performed when Pinus tabuliformis roots at a moisture content of 37%-45% and Larix principis-rupprechtii roots at a moisture content of 20.4%～28.05%.(4) Cellulose content, hemicelluloses content and holocellulose contnet had a significantly positive correlation with root diameter and tensile resistance of Pinus tabuliformis and Larix principis-rupprechtii, but no correlation could be observed with tensile strength; Cellulose content, hemicelluloses content and holocellulose contnet had a significantly negative correlation with root diameter and tensile resistance of Betula platyphylla and Quercus mongolica, also had a significantly positive correlation with root tensile strength. Lignin content and L/C had a significantly negative correlation with root diameter and tensile resistance of Pinus tabuliformis and Larix principis-rupprechtii, but no correlation could be observed with tensile strength; Lignin content and L/C had a significantly positive correlation with root diameter and tensile resistance of Betula platyphylla and Quercus mongolica, also had a significantly negative correlation with root tensile strength.(5) Root tensile resistance had a significantly positive correlation with diameter, L/C and holocellulose of Pinus tabuliformis and Larix principis-rupprechtii, tensile strength had no significant correlation with main chemical components. Root tensile resistance had a significantly positive correlation with diameter and L/C, also had a significantly negative correlation with lignin of Betula platyphylla and Quercus mongolica, tensile strength had a significantly positive correlation with holocellulose.更多还原