Numerical Simulation of Rockfill Materials Based on Fractal Theory

Abstract

With the use of the particle flow code in two dimensions, a fractal model is established with the number of particles of different particle fractions used as the statistics to study the fractal characteristics of particle size distribution. Numerically simulated specimens obtained by four scale methods are subjected to the relative density test and the biaxial compression test to explore the influences of fractal dimension D on the macroscopic and mesomechanical properties of specimens, as well as to study the relationship between fractal dimension D and different mechanical performance indexes. Results show that the particle size distribution of each of the four groups after scale exhibits fractal characteristics, with the fractal dimension D ranging from 1.27 to 2.03. The number of fine particles in the specimen increases with the fractal dimension D, the particle aggregates become more compact, the macroscopic mechanical properties of the specimens are improved, and a linear relationship exists between the fractal dimension D and different mechanical performance indexes. A large fractal dimension D corresponds to a great mesoparticle coordination number.

Study on the detection of apple soluble solids based on fractal theory and hyperspectral imaging technology

“…The fractal theory is a science that studies a kind of irregular, chaotic and complex system with local and global similarities (Zhao et al, 2022). Fractal dimension is a basic measure used to describe the irregularity and self-similarity of objects in fractal theory (Acquisgrana et al, 2022;Han et al, 2022). In this paper, fractal dimension is proposed as a method to identify spectral characteristics to explore the relationship between fractal dimension and soluble solid content (SSC).…”

Influence of Scale Effect on Strength and Deformation Characteristics of Rockfill Materials

“…As the main filling material of earth rock dams, rockfill materials are widely used because they can be adapt to more complex geological conditions [ 1 , 2 , 3 ]. Block stone, crushed stone, stone slag, sandy soil, stone chips, backfill, and mixed soil containing a large number of coarse particles in cohesive soil are materials often used in engineering [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. At present, with the continuous increase in the height of earth rock dams, the particle size of rockfill materials is also larger, some of which reach 600~800 mm, and some even reach 1000 mm [ 10 , 11 ].…”

“…Block stone, crushed stone, stone slag, sandy soil, stone chips, backfill, and mixed soil containing a large number of coarse particles in cohesive soil are materials often used in engineering [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. At present, with the continuous increase in the height of earth rock dams, the particle size of rockfill materials is also larger, some of which reach 600~800 mm, and some even reach 1000 mm [ 10 , 11 ]. Under the indoor triaxial test condition [ 2 ], the maximum particle size of the sample shall not exceed 1/5 of the sample diameter D. Limited by the size of the test instrument.…”

“…The rockfill materials that exceed the maximum allowable particle size for the test must be reduced. There are great differences in the macro mechanical properties of rockfill materials replaced by scales of different sizes [ 3 , 10 , 11 , 12 , 13 ], which is the scale effect. In recent years, the research on scaling effect mainly focuses on two aspects [ 2 ]: on the one hand, it is to increase the sample size and restore the in situ size of rockfill as much as possible to reduce the impact of scaling [ 1 , 12 , 14 ].…”