| The particle shape of rock and soil can affect many physical and mechanical properties of the granular materials,such as strength,density of accumulation,natural angle of repose and permeability of rock and soil.At present,the objective method is generally used to evaluate the particle shape,and the evaluation results are subject to subjective influence.Based on the image processing technology,the program of particle shape quantification is developed.Taking desert sand and rock flakes as the research object,the shape parameters of sand particles and rock mineral particles are calculated,namely,particle size P_S,sphericity S,convexity C,aspect ratio A and roundness∏.The main research results of this paper are as follows:(1)The program consists of three steps.Firstly,the particles in micrographs are distinguished by image segmentation technology.Secondly,the pixel contour coordinates of particles are extracted for discrete geometric analysis,and finally the particle shape parameters are calculated.The influence of image resolution R_e,particle profile fitting degree R~2and corner key point grouping coefficient a on the calculation results of particle shape parameters is also analyzed.(2)The program is used to analyze the sand particles in Taklimakan Desert,and it is found that the particle morphology and characteristic parameters of 46 sampling points are similar,showing high self similarity.The average particle size of 448 particles in the 46 groups above is67.47μm.The average ball degree is 0.76,the average convexity is 0.94,the average ratio of length to width is 0.70,and the average roundness is 0.38.(3)The program is used to analyze the mineral particles in marble and sandstone slices.It is found that the average value of particle shape parameters is close to that of the same rock sheet,although the mineral types are different.The program can be used to assist in the identification of rock flakes,and make the description of mineral particle morphology more objective. |
