The Research Of Mechanical Property Of Tree Root And Its Influence Factors

Vegetation limits the frequency and spatial distribution of shallow landslide initiation by providing fibre to reinforce soil. The magnitude of fibre reinforcement effects largely depend on stretching resistance performance of roots. For select the better vegetation to stabilize slope, and give full play to soil fixation effects of roots, based on basic theory of material mechanics, soil mechanics, elastic-plastic mechanics, plant fiber chemical science, we chose three common trees grown in north China:Pinus tabulaeformis, Betula platyphylla, Quercus mongolicus, and analyze strentching resistance performance of roots and its influence factors. We systematically discussed relationship between three root tensile mechanical properties and main chemical compositions cellulose content, lignin content and hemicellulose content, to reveal root mechanics foundation of soil-reinforcement and its influence factors.The major results were summarized as follows:(1) Significantly different was founded between different root preparation methods, rehydrating of fresh roots after drying significantly increase root tensile strength.(2) We measured tensile strength of three tree species roots with our improved experiment methods, we found maximum tensile force of roots positively related to its diameter (power function). Order of tensile force ability:Betula platyphylla.>Quercus>Pinus tabulaeformis;(3) Moisture is one of the dominant factors controls on root tensile strength, root tensile strength significant increase with decrease of moisture, thus we should measure and control moisture of root in our experiment;(4) Cellulose content, hemicellulose content and holocellulose content of the three trees roots increase with increase of diameter, while lignin content and L/C decreased with increase of diameter; tensile force increase with increase of cellulose content, hemicellulose content and holocellulose content, decreased with increase of lignin content and L/C;(5) Limit tension strain of root was different between different tree species; it decrease with increase of cellulose content, hemicellulose content and holocellulose content, and increase with increase of lignin content and L/C.(6)Root tensile mechanical properties are affected by all chemical compositions and largely related to root micro structure.