Abstract: The shape of particles reflects the history of particle formation and is one of the main control indices that determine the strength characteristics of cohesionless soils. To study the influence of the particle shape on the mechanical properties of sandy soils, A total of six (6) types of sand samples with different average particle sizes as well as different shapes are selected as the research object. The digital image of the particles is obtained by using the dynamic image capture technology, and the two-dimensional data are extracted by the computer digital image processing system and processed to quantify the shape parameter. A new shape factor (ρ) index from the particle sphericity and roundness indices to describe the shape of aggregate particles is proposed. The results show that the boundary void ratio and compressibility index (C_c) of the sample increase as (ρ) decreases. The rebound index (C_s) decreases with the decrease of (ρ); the experimental results also show that the number of particles breakage increases with the decrease of (ρ) and the sample develops from the poorly graded to the direction of well-graded.

Key words: Particle Shape, Dynamic Image, Maximum and Minimum Void Ratio, Compressibility Index, Rebound Index, Particle Breakage