The Shear Characteristics Of Four Kinds Of Plant Root Damaged By Shear Stress After Its Self-repairing

In this paper,taking Caragana microphylla,Salix psammophila,Hippophae rhamnides and Artemisia sphaerocephala as research object.The shear strength of root-soil composite of 4 kinds of annual plants were measured through in-situ shear tests,on this basis,exerted a force of different damage degree to 4 kinds of plants After its self-repairing 3 months and 5 months,research the shear properties of plant root damaged by shear stress after its self-repairing,The results are as follows:(1)Under the same lateral confinement,the total root length,root surface area,root volume and root dry weight of the four species follow the sequence of Psammophila>Microphylla>Sphaerphala.>Rhamnides,The shear strength of 4 kinds of plants and RAR of the shearing surface shows a positive correlation.The shear strength of root-soil composite of 4 kinds of plants followed by Psammophila(16.57±2.73)kPa>Microphylla(9.83±2.52)kPa>Rhamnides(7.59±1.17)kPa>Sphaerpha la(7.34±1.48)kPa>Plain soil(5.39±0.79)kPa;The residual strength of followed by Psammophila(9.69±2.34)kPa>Microphylla(6.41±1.80)kPa>Rhamnides(3.70±1.15)k-Pa>Sphaerphala(3.17±0.87)kPa>Plain soil(2.51±0.42)kPa,The results showed that the roots can significantly improve the shear strength and residual strength of soil,effectively enhance the stability of soil.(2)After 3 months of self-repaired,the survival rate of 4 kinds of plant roots was higher than 83.3%under three degrees of damage force(25%,50%and 75%of ultimate shear force),the survival rate was more than 90.9%after 5 months of its self-repaired.The survival rate of 4 kinds of plants and damage force shows a negative correlation.(3)After 3 months of 4 kinds of plants self-repaired under three degrees of damage force,the shear strength and residual strength of root-soil composite are higher than the plain soil,but lower than that of the parallel contrast.when damage force was 25%of ultimate shear force,the shear strength and residual strength of 4 kinds of plant were lower than that of parallel contrast,when damage force was 75%of ultimate shear force,the parallel contrast and the shear strength and residual strength of root-soil composite after 3 months of its self-repaired have significant diffrernce.the ratio of shear strength and residual strength of 4 kinds of plants after its self-repaired to the parallel contrast followed by Psammophila>Microphylla>Rhamni-des>Sphaerphala.(4)The longer the roots self-repairing,the shear strength and residual strength of Microphylla,Rhamnides and Sphaerphala root-soil composite was close to that of parallel contrast,Psammophila root-soil composite was less affected by self-repairing time.