Study On Mechanical Characteristics And Root System Distribution Of Slope Protection Plants On Highway

Nowadays, the ecological environment is destroied with large-scale construction ofhighway in our country. In particular, when the sloping body is filled highly and dug deeply,its stress is redistributed which can cause instability of slope easily disintegration and slump.It is a critical threat to the highway traffic safety and influence the civilization construction ofecological highway. So the study on the root distribution and mechanical characteristics ofslope protection plants on representative highway in the loess plateau is helpful tounderstanding the mechanism of slope protection better and enhance slope stability. And itwill provide a scientific guiding significance to the selection and allocation of slopeprotection plants on highway.Herbs play a significant role in the slope protection of highway. Therefore we study theaction of root on the improving effect of slope stability in aspect of tensile, resistant ofdisintegration and compress, and etc, on the basis of analyzing the root distribution ofTrifolium repens L, Coronilla varia, L.perenne and pratensis, and its mechanical properties.By principal component and comprehensive analysis of the effect of enhancing stability ofslope, the following four results were obtained:(1) The average length density of the four plants root in the soil surface (0-20cm) wassorted in the following order: L.perenne (8.0cm/cm~3), pratensis (2.83cm/cm~3), Trifoliumrepens L (0.41cm/cm~3), Coronilla varia (0.20cm/cm~3). Root biomass was sortedasL.perenne> Coronilla varia> pratensis> Trifolium repens L. Besides Coronilla Varia,maximum length density of other three plants root was in a range of0-5cm horizontally andvertically, and length density decreased exponentially with the increase of soil depth.(2) Plant roots’ anti rally was sorted in the following order: tensile: Trifolium repens L>Coronilla Varia> pratensis> L.perenne. There was a significant negative power functioncorrelation between roots’ ultimate tensile strength and diameter. The roots’ stress-strainrelationship reflected that L.perenne had a strong ability to resist deformation, and root tensileelongation was sorted by grasses, shrubs and legumes.(3) Disintegration rate from fast to slow was in the order of Coronilla Varia, Trifoliumrepens L,pratensis and L.perenne. Soil depth and root content were two factors that affect soildisintegration rate. Disintegration rate reduced with the increasing of soil depth, and it wasgreater in no root soil than root soil. There was a significant negative linear correlation between specific root length in soil samples and disintegration rate.(4) The order of the compressive strength was L.perenne, pratensis, Trifolium repens L,Coronilla varia. Fibrous root system of gramineous plant root soil complex compressivestrength was greater than legumes. The larger plant specific root length had greater effect onresistance of stress, while there was no significant correlation, and the resistance of stress wasstronger in the deeper soil layer.By principal component analysis it was concluded that the order of the four plants in theaspect of improving soil stability and the comprehensive effect of slope protection wasL.perenne> pratensis> Coronilla varia> Trifolium repens L.