Test speed and other factors affecting the measurements of tree root properties used in soil reinforcement models

• Published in: Soil & tillage research Vol. 63; no. 1; pp. 51 - 56
• Main Authors: Cofie, P., Koolen, A.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2001; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Beech; Biological and medical sciences; Clamping; Economic plant physiology; Elongation rates; Fundamental and applied biological sciences. Psychology; Generalities and techniques; Leerstoelgroep Bodemtechnologie; PE&RC; Soil Technology Group; Strain; Stress; Tensile strength; Elongation rates; Clamping; Beech; Tensile strength; Stress; Strain; Speed; Root; Strain energy; Mechanical properties; Soil reinforcement; Fagaceae; Elongation at fracture; Soil vehicle interaction; Dicotyledones; Angiospermae; Hardwood forest tree; Spermatophyta; Fagus sylvatica
• ISSN: 0167-1987; 1879-3444
• DOI: 10.1016/S0167-1987(01)00225-2

Measured values of the mechanical properties of tree roots are found to be affected by a number of factors. Shear properties of tree roots are found to be partly influenced by size of the testing equipment, level of soil compaction, deformation of the root material and estimated width of the shear zone in the soil, etc. Among others, tensile root properties are found to be affected by factors such as season, age, root types or species, root preparation before experiment, clamping procedure of the root, and rate of elongation used. The aims of this paper were (1) finding an appropriate clamping procedure for root measurements; and (2) studying the effect of elongation rate on stress–strain relationships of beech (
Fagus sylvatica L.) roots. It was found that problems associated with root clamping (i.e., in root experiments) such as breakage of the root sample close to the jaws of the clamping devices and slippage may be eliminated by introducing wooden blocks of appropriate hardness within the jaws of the clamps and exerting a suitable clamping force, respectively. An appropriate wood hardness and suitable clamping force were found by conducting a number of initial trial experiments. Tensile experiments conducted with beech roots pairs showed that elongation rate does influence the stress–strain relationships of roots. In general, stress values of beech roots were found to increase between 8 and 20% for an increase in the rate of elongation from 10 to 400
mm/min. Similar findings have been reported in textile fibres.