Study On The Mechanical Mechanism Of Grass-Root Soil Consolidation And Its Influence On The Stability Of Soil Slope Surface

In recent decades,the technology of plant slope protection has gained a lot of engineering applications.However,more in-depth research is needed on the mechanism of slope protection.Especially in the numerical simulation of root slope protection,most scholars simply regard the root as an anchor,and do not make a correct reflection on the complex growth process and shape of the root system.Based on the theory of plant physiological morphology and the self similarity and self-adaptability of plant root system,the simulation model of root growth is built on the basis of topological optimization principle and L-system theory to express the topological structure of the root system configuration of herbaceous plants.Based on the experiment of planting ryegrass and the measurement of root growth parameters,the rules of root morphology and growth law of ryegrass were abstracted.On this basis,the relative numerical simulation of the shallow slope of the root system is carried out,the mechanism of soil interaction is discussed,the reinforcement effect of different conditions is evaluated,and the estimation method of the influence of the interaction of root and soil on the stability of the shallow surface of the slope is proposed.The main achievements and conclusions are as follows:(1)on the basis of extensive collection of relevant data at home and abroad and summarizing the achievements of previous studies,the theories needed to study the mechanism of soil solid soil consolidation are summarized,including the principle of the growth and development of plant roots and the reinforcement theory of the root soil fixation of herbaceous roots,for the morphological simulation of the root system and the root soil interaction machine.The research of the system has laid the foundation.(2)a regular description of the morphology and growth pattern of rye root system was abstracted through the planting experiment.Based on the theory of plant physiological morphology and the self similarity and self-adaptability of plant roots,the morphology and growth model of rye root system were constructed based on the topology optimization principle and L-system theory.(3)the tensile strength of the root system of rye was measured at different growth stages by drawing test.It was found that the root tensile strength increased with the growth of root system,but the increase rate was more and more slow and then stable at about 12.5Mpa.The change law of the strength index of the soil and root soil complex atdifferent growth stages was measured by direct shear test.It is found that the growth law of the complex is approximately the same as that of the root growth function.(4)using the morphological simulation results of rye root system,combined with the mechanical parameters of the soil and the root system obtained from the laboratory test,the direct shear model of the root soil was established by the numerical simulation software,and the direct shear simulation was carried out according to the root distribution model in different periods.The mechanical parameters obtained by the simulated calculation and the sampling test in the same period were calculated.Comparing the number,we found that the difference between the two was small,which verified the reliability of the root simulation results.(5)the numerical simulation software was used to establish the shallow slope and the root system slope model.The effects of root and soil on the soil displacement and stability of the surface soil surface under the condition of self weight were studied according to the planting density of different roots,the root form and the different slope angle conditions,and the reinforcement effect under various conditions was evaluated,and the results were established.Estimation formula of root planting density,root growth time,and slope slope angle and slope stability coefficient.Through this study,the growth morphology model of rye root system was discussed,the mechanical mechanism of rye root system strengthening shallow slope was analyzed,and the reinforcement effect of rye grass root system on the shallow surface of soil slope under various conditions was evaluated,which provided a certain theoretical basis for plant slope protection engineering.