Study On Mechanical Properties Of Self-Healed Artemisia Ordosica Krasch.Roots After Erosional Force Damage

The Artemisia ordosica Krasch.which is the common plant in the Semi-arid mining area was used to the study object.The biological and mechanical properties of straight root?lateral root branch and the root-soil composite of Artemisia ordosica Krasch.which are under the condition of self-healing for 3 and 5 months after damaged by erosional force,Results are as follows:(1)The survival rate of the whole plant root-soil composite was higher than 70%after the self-healing of the damage produced by gradient shear,the plant height,crown breadth and ground diameter increased compared with that before the damage,and the above-ground biomass and dry weight of roots were significantly higher than the control group which measured before the damage.(2)The shear strength respectively increased by 31.91%and 12.32%,and residual shear strength respectively increased by 35.10%and 23.95%compared with plain soil,after 3 months of self-healing as the root-soil composite sustained slight and severe shear force(30%and 70%of the average maximum anti-shear force),but still less than that of the control group.After 3 months of self-healing which sustained the slight and severe shear force,the shear strength was 82.19%and 63.83%of the control group respectively,and residual shear strength was 77.58%and 66.21%of the control group respectively.That is to say,with the increase of the self-healing period,the strength of the root-soil composite of the whole plant was continually increased,the restoration of the root-soil composite was not completed after self-healing of 5 months.(3)After self-healing of 3 months of the damage produced by gradient tension and fracture force,for the straight root and lateral root branch,the anti-tension and anti-tension strength were also higher than the control group before the damage,and so were the anti-fracture force and anti-fracture strength.When sustained the slight and severe tension and fracture force(30%and 70%of the average limiting force),compared with the control group,the tensile strength of the straight root respectively decreased by 5.19%and 16.00%,the lateral root branch respectively decreased by 16.01%and 37.89%;The anti-fracture strength of the straight root decreased respectively by 8.86%and 20.90%,the lateral root branch respectively decreased by 13.25%and 23.90%;The self-healing time extended from 3 months to 5 months,the decrease rate of anti-tension strength and anti-fracture strength of straight root showed a decreasing trend.(4)For the root-soil composite of Artemisia ordosica Krasch.of the whole plant:the greater the degree of shear damage,the smaller the shear strength and residual shear strength after self-healing.For the straight root and lateral root branch:the greater the degree of tension damage,the smaller the tensile strength after self-healing,and the change of anti-fracture strength is the same as the above law.The lateral root branch,which easily damaged by axial tension force and radial fracture force,is a part that not easily repaired.The radial fracture force is the vulnerable load at the straight root and lateral root branch,the radial fracture force is the load which repaired difficulty at the straight root,the axial tension force is the load which repaired difficulty at the lateral root branch.