The traditional evaluation method of cohesionless soil based on particle size and gradation can't give a reasonable explanation for the unique engineering characteristics of soil with irregular particle shape.
Researchers from the Institute of Rock and Soil Mechanics of the Chinese Academy of Sciences summarized scientists' research achievements in physical characterization, numerical simulation and laboratory experiments of particle shape.
The results show that the particle shape description is mainly based on three scales (form, roundness and surface texture). The numerical simulation method can simulate the shape of a single convex particle and the arrangement structure of the aggregate, but the precision of the concave particle is not ideal. There is a correlation between particle shape and pore structure, natural angle of repose, limit pore ratio and particle size. Under the same conditions, the particle shape affects the permeability coefficient, small strain strength, peak strength and participation strength of aggregate. This study summarized the current research status of particle shape and prospected the future research work of particle shape.
The results have been published in Rock and Soil Mechanics. It was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDA13010203), the General Program of National Natural Science Foundation of China (41877271，41572304) and the Hubei Natural Science Foundation(2020CFB243).
Fig.1 Sketch of grain shape parameters
Fig.2 Determine the Sphericity by look-up table
Fig.3 Determine the roundness by contrast picture