Research And Application On Strength Characteristic Of Granular Materials Based On Two-dimensional Fractal Particle Size Distribution Model

The strength characteristic of granular materials is an important research field in geotechnical engineering.Particle size distribution,as an important property of granular materials,is a key factor affecting its strength characteristics.However,existing research cannot quantify the relationship between them.The two-dimensional fractal particle size distribution model is a new particle size expression method,and its parameters can fully reflect the mathematical characteristics of granular material particle size distribution.Therefore,the particle size distribution of the granular material can be determined based on the model parameters,and then the strength index can be obtained by performing the corresponding test,so as to study the strength characteristics of the granular material and apply it to engineering practice.The purpose of this paper is to study and apply the strength characteristics of granular materials based on the two-dimensional fractal particle size distribution model.Firstly,the two-dimensional fractal particle size distribution model is introduced,and based on the model,the fractal characteristics of gravel and sand grains in fine grained soil is analyzed.The gravel group selects pebble and the sand group selects coarse sand.The mixing of materials is controlled by the five main model parameters for the particle size distribution of the mixed materials,so that different particle grading test materials can be obtained.Based on the theory,the model can be applied to the strength of mixed material of pebble and coarse sand.The feasibility of the study of characteristics.Secondly,the specimens is prepared under the grading parameters of the model,and the specimens is subjected to a large-scale direct shear test in accordance with a fixed relative density.After a large number of indoor large-scale direct shear tests and corresponding control and review tests of mixed materials of crushed gravel and coarse sand,the shear strength indexes of the samples under the change of five different model parameters,and get the qualitative relationship between the shear strength index and the model parameters is obtained.Thridly,using MATLAB and its genetic algorithm toolbox to analyze the data of this experiment,it can get the corresponding fitting formula.Analogous to this process,to analyze the relationship between the three sets of granular material model parameters and its permeability coefficient based on the two-dimensional fractal particle size distribution model,and the uniform form of the permeability coefficient represented by the model parameters is obtained.This process which based on the two-dimensional fractal particle size distribution model to study the strength characteristics of the granular material is successfully.Finally,based on the research results of the granular materials' strength characteristics,the Dong'an Quarry retaining wall is redesigned.This design combined with the research results of the two-dimensional fractal particle size distribution model not only solves the design difficulties of the Dong'an Quarry retaining wall,but also provides engineering references and references for similar retaining walls and for evaluating the shear strength of granular materials through particle size distribution.