Effect And Mechanism Of The Fixed Slope Of Sea-buckthorn Root System In The Sandstone Area

The sandstone area is the core area of the coarse sand and sand area in the Yellow River,which is a severely eroded area of the Loess Plateau.The sea-buckthorn is the main plants which can maintain the soil and water in the sandstone area,as well as solid slope protection.Researched it the mechanism of solid soil slope protection,this paper selects sea-buckthorn plant root as research object,discussed the characteristics of root morphology distribution of sea-buckthorn,the tensile properties of single root,the shear properties of root-soil complex and the main influencing,based on field experiment and indoor experiment,according to the experimental data,through theoretical analysis.This paper can provide theoretical basis and reference for the design and the planting parameters of the protective slope of sea-buckthorn vegetation.It can also lay a foundation for the subsequent system to study deeply the slope protection effect,soil and water protection mechanism of solid sea-buckthorn.The main research conclusions are as follows:(1)The sea-buckthorn root length,root volume,and root weight are mainly concentrated in the soil layer of 0-45 centimeter,which is a shallow root system.The sea-buckthorn root length accounted for 83.9%;root weight accounted for 89%;root volume accounted for 81.3% in the 0-45 centimeter soil layer.of The sea-buckthorn hair roots were developed,which root diameters were concentrated between 0-2mm millimeter,root volume accounted for 90.3%;root length accounted for 57.2% in this range.The presence of a large number of hair roots significantly improved the slope stability.(2)This paper uses Sketch Up software to reproduce the sea-buckthorn root system stereoscopically.According to slope stability theory,the greater the slope,the smaller the slope safety factor.Meanwhile,the slope value of the sea-buckthorn sprouting propagation is 59°,but the slope of the Up-slope slope is greater than 59 ° through the non-linear fitting of the Up-slope primary roots and the included angles on the slope surface.(3)The single root tensile strength of sea-buckthorn is affected by factors such as root diameter,gauge length,and loading rate.The maximum tensile strength of sea-buckthorn single root was positively correlated with diameter,loading rate,and negatively correlated with the gauge length;the tensile strength was negatively correlated with diameter,gauge length,loading rate.The elastic modulus,ultimate elongation as well as the tensile strength,tensile strength are mainly affected by the root diameter.The root of sea-buckthorn satisfies Hooke’s law at the initial stage of stress,demonstrating its elastic material properties.There are five types of stress-strain curves for sea-buckthorn roots: zigzag,bimodal,linear,convex,and multimodal types.(4)There is a positive correlation between shear strength and vertical load of sea-buckthorn root-soil composites,which is consistent with the Mohr-Coulomb theory.The total cohesion of the composite is increased compared to that of plain soil,and the maximum increase is 2.65.The cohesive force of the root-containing soil first increases and then decreases with increasing water content.There is an optimal moisture content between the complexes,roughly 13% to 13.81%.When the sea-buckthorn root-soil complex approached this range of moisture content,the cohesion and shear strength reached a maximum.The effects of root volume and soil water content on the internal friction angle were not significant,indicating that the slopes were mainly stabilized by the effect of cohesion between the composites.