油松、华北落叶松根系抗拉特性的影响因素

植物根系的抗拉特性是影响边坡稳定性最重要的因素。为探究根系的基本力学特性及影响因素,选取不同直径、保存时间的油松、华北落叶松根系在不同标距、拉伸速率下进行室内拉伸试验,并运用方差分析、协方差分析、多元回归分析等数学统计方法对其进行定量、定性分析。结果表明:油松、华北落叶松根系抗拉力与直径呈幂函数正相关关系,而抗拉强度与直径无明显关系;标距、拉伸速率均对根系抗拉力、抗拉强度有显著影响,并且与根系抗拉力、抗拉强度均呈负相关关系,不同标距下2个树种根系的抗拉力、抗拉强度均表现为50 mm100 mm150 mm200 mm,不同拉伸速率下2个树种根系的抗拉力、抗拉强度均表现为10 mm/min100 mm/min200 mm/min;在不同试验条件下,油松根系的力学性能均优于华北落叶松根系;各个影响因素对根系抗拉力、抗拉强度的回归模型表明,根系直径是影响根系抗拉力的最主要因素,而且标距对抗拉力、抗拉强度的影响大于拉伸速率,根系保存时间对抗拉力、抗拉强度没有显著影响。 

Factors influencing root tensile properties of Pinus tabuliformis and Larix principis-rupprechtii

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 and Larix principis-rupprechtii as our experimental species, classified roots by diameter and storage time, and conducted tensile test indoors at different gauge lengths and different tensile rates. In addition, statistical methods including variance analysis, covariance analysis and multiple regression analysis were used to investigate the relationship between root tensile properties and the influencing factors. The results showed that root diameter had a significantly positive correlation with root tensile resistance of P.tabuliformis and L. principis-rupprechtii and their relation accorded with the power function, but no correlation could be observed between tensile strength and root diameter. Gauge length and tensile rate had significantly negative correlations with root tensile resistance and tensile strength. The root tensile resistance and tensile strength of the two species at different gauge lengths followed a descending order as 50 mm100 mm150 mm200 mm; the root tensile resistance and tensile strength of the two species at different tensile rates descended as 10 mm/min100 mm/min200 mm/min. At the same level of different factors, the mechanical properties of single root of P. tabuliformis were better than those of L. principis-rupprechtii. The regression model about the impact of various factors on the root tensile resistance and tensile strength showed that: 1) root diameter was the main factor affecting the tensile resistance; 2) the impact of gauge length on tensile resistance and tensile strength was greater than the impact of tensile rate; and 3) root storage time had no significant effect on root tensile properties.