Study On The Mechanical Properties Of Caragana Root Materials

In this paper,the roots of the 4-year-old pioneer plant species of Caragana korshinskii planted in the semi-arid loess hilly region and Linger County of Inner Mongolia Autonomous Region are taken as the research objects.The combination of in situ tests in the wild natural habitat and indoor simulation experiments was used to study the root system through straight root tensile and flexural tests,root-soil composite direct shear test and root-soil interface friction test,etc.Soil mechanical properties,analysis of straight root tensile strength,flexural mechanical strength index,root-soil composite shear strength and its strength index,root-soil interface friction characteristics and influencing factors,etc. characteristic.The following results are obtained:(1)The morphological and quantitative distribution characteristics of the root system of Caragana korshinskii standard plants determined that the representative root diameter of Caragana korshinskii was 0-0.5mm,0.5-lmm,1-1.5mm.(2)In the range of the test root diameter of 0-2mm,the instantaneous ultimate tensile strength(23.79N±14.74a)>ultimate bending strength(23.52N±17.10a),ultimate tensile strength(36.02Mpa ± 21.16a)>The ultimate flexural strength(21.17Mpa ± 11.36b),the root system of Caragana korshinskii is susceptible to breaking force.(3)After 50 cycles of loading-unloading-reloading fatigue,the straight root ultimate tensile strength of Caragana microphylla is 75%gradient(56.03N ± 40.71 a)>35%gradient(43.56N± 30.49b)>55%Gradient(41.52N±26.86b)>Parallel control group(19.12N±16.36c),ultimate tensile strength 75%gradient(88.65Mpa±65.57a)>55%gradient(60.67Mpa ± 37.97b)>35%gradient(55.16Mpa±30.5c)>Parallel control(25.69Mpa ± 18.14d),the root tensile strength and tensile strength increased significantly after fatigue;the Caragana root system had a certain repair ability after three months of injury after being damaged by tension.(4)Under the vertical load of 12.5kPa(about 0.8m in the concentrated soil layer of root system),the shear strength and cohesion of the Caragana korshinskii root-soil complex first appeared with the increase of soil moisture content,number of roots and root diameter After the increase,the tendency to decrease,the cohesive force has a significant effect on the increase of the root-soil composite shear strength.(5)Under natural conditions,the shear strength and its index and friction coefficient of the root-soil interface of Caragana korshinskii are larger than that of the soil-soil interface,and the root system has the effect of solid soil anti-cracking;in the range of 1-4mm in test diameter,Caragana korshinskii The straight root resistance tensile force increases with the increase of the root diameter,and the drawing shear strength decreases with the increase of the root diameter.