Background and Aims

Roots of plants have been shown to be effective in reinforcing soils against slope failures. Two key mechanical properties in such reinforcement are the root’s tensile strength (TS) and elastic modulus (EM). However, knowledge on the combined effects of root moisture content (RMC) and root diameter on these properties is scarce. The study aims to quantify these relationships for root samples of four native Australian tree (A. costata, B. integrifolia, E. reticulatus, and E. racemosa).

Methods

A series of tensile tests were conducted and the root diameter at the fracture point and RMC were measured immediately after each test. Data were analysed using both univariate and multivariate analyses.

Results

Both TS and EM declined with increasing diameter. Power-law expressions were found to describe the relationship between TS and diameter moderately well, but less so the one between TS and RMC. Multivariate analyses yielded a double power-law for TS versus diameter and RMC with a stronger fit than univariate ones. A weaker power-law was found between EM and these 2 variables. Of the four trees tested, A. costata exhibited the highest tensile strength and elastic modulus at a 1 mm diameter, while B. integrifolia yielded the lowest.

Conclusion

Considering both diameter and RMC as explanatory variables of TS and EM yield better accounts of experimental data. This work contributes to a better understanding of reinforcement capacity of trees generally, as well as the specific performance of roots of four native Australian trees.

中文翻译：

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直径和含水率对四种澳大利亚本土树木生物力学特性的影响

 背景和目标

植物的根已被证明可以有效地加固土壤以抵抗边坡崩塌。这种增强材料的两个关键机械性能是根的拉伸强度 （TS） 和弹性模量 （EM）。然而，关于根水分含量 （RMC） 和根直径对这些特性的综合影响的知识很少。该研究旨在量化四种澳大利亚本土树木（A. costata、B. integrifolia、E. reticulatus 和 E. racemosa）的根样本的这些关系。

 方法

进行了一系列拉伸试验，并在每次试验后立即测量断裂点的根直径和 RMC。使用单变量和多变量分析对数据进行分析。

 结果

TS 和 EM 均随着直径的增加而下降。发现幂律表达式可以很好地描述 TS 和直径之间的关系，但 TS 和 RMC 之间的关系则不那么好。多变量分析产生了 TS 与直径和 RMC 的双幂律，比单变量更强。在 EM 和这两个变量之间发现了一个较弱的幂律。在测试的四棵树中，A. costata 在直径为 1 mm 时表现出最高的拉伸强度和弹性模量，而 B. integrifolia 的产量最低。

 结论

将直径和 RMC 视为 TS 和 EM 的解释变量可以更好地解释实验数据。这项工作有助于更好地了解树木的加固能力，以及四种澳大利亚本土树木的根的具体表现。