Study On Physical Mechanism Of Interface Between Root System And Loess Soils

Based on theoreis and methods in elasto-plasticity mechanics, soil mechanics, soil & water conservation, forest ecology and etc., the study has made both field and lab experiments, including: establishing roots configuration model for plantation trees of R.pseudoacacia and Pinus tabuleeformis; building-up constitutive model of roots based on studing the stress-strain relationship of pine tree; analyzing the elements effecting the interface friction and developing the interface element constitutive model; analyzing the effects on horizontal, vertical and complex root-soil composite on stress-strain of root-soil composite by using triaxial test; stimulating the root-soil composite displacement, strain and analyzing the effects of single tree-root and multi-trre-roots on stress-strain by using finite element method. The objectives of the study are to reveal the mechanism between roots and soils in order to provide a theoritical basis for assessing the effects of roots on the stability of non-saturation soil slope and slope control.The major achivements are the following:1. Pinus tabuleeformis is vertical rooted while R.pseudoacacia is horizontal. Both trees' horizontal roots have a power relationship with the breast-height diameter and also with the main root and with biomass of roots. Based on Fitter and Rose description and rule, the root configuration modes for both trees are established.2. The root drawing test shows that for Pinus tabuleeformis roots the stress and strain has a linear relationship in the early drawing stage when is in the elastic phase. But if the stress is over the drawing resistance threshold of resistance by 50%-70%, the relationship between...