Research On Optimization Of Soil Consolidation Model Considering Root Morphology Distribution

Slope instability and soil erosion which result serious economic and social damage are the most important environmental hazards today.Vegetation is an important factor in maintaining ecological balance.Vegetation can reduce the risk of slope instability and erosion.Therefore,it is of great theoretical significance and engineering application value to study the influence of different root architecture on the strength of root-soil composites,reveal the mechanism of root-reinforced soil,and establish an optimal root-reinforced model.The research is supported by the National Natural Science Youth Fund Project "Research on the Mechanism of Plant-reinforced Soil Based on Root Structure"(Project No.51608545).Experimental and theoretical about the strength characteristics of the root-soil composites were carried out based on the roots of vetiver and Changsha clay.Theoretical analysis and experimental research were used to study the morphological characteristics of vetiver,root tensile strength and strength of root-soil composites.The main research results and innovative conclusions are as follows.(1)The morphological parameters of root system of vetiver in different growth stages were obtained.And the regularity of different root morphological parameters with the growth period were summarized.It's shown that the number and length of vetiver roots increase indexed with the growth of plant,lateral extension width and root dry weight increase linearly with the growth of plant in a certain range,but the root diameter does not change with the growth of vetiver.(2)The tensile strength of vetiver roots and the stress-strain relationship during stretching were obtained by tensile test and on-site drawing test.It's found that the tensile stress-strain relationship of vetiver roots is elastoplastic.The tensile strength decreases with the increase of diameter.The elastic modulus of vetiver can reach 750 MPa.(3)The triaxial test on the remolded roots with different root contents was carried out.It is verified that the shear strength and the cohesion of the root-soil composite increases as the root content increase at a certain water content.When the volume content of vetiver roots was 0.18%,the cohesive value of the root-soil composite increased by 69.6%compared with the unreinforced soil,and the internal friction angle value increased by 13.5%(4)A two-phase constitutive model considering the interaction of roots and soils was established.The two-phase model can well reflect the stress-strain relationship of the triaxial shear of the root-soil composite.It can predict the modulus and strength of the root-soil composite according to the root volume content and distribution function.(5)Direct shear tests on remolded root-soils with different root morphology were carried out.The shear strength characteristics of root-soil composites with different root morphology were researched.The relationships between spatial distribution angle of roots and the shear strength of soils were established.The mechanism of the roots with different root morphology in the landslide was revealed.It's shown that when the slope soil is sheared,only the roots which are stretched can resist the sliding force of the soil?...