Evaluation of particle size distribution of granular blasting materials based on the fractal theory

Jiejie Ji,Qiang Yao,Faming Wu,Hongtao Li

doi:10.1177/1687814019881562

Abstract

The particle size distribution of granular blasting materials has a vital influence on the filling quality of earth-rockfill dams. The engineering experience-based method used to evaluate the particle size distribution has shortcomings at both the theoretical and practical aspects. This article proposes a new evaluation method based on the fractal theory. Grading sieve tests on granular materials, mass fractal analysis of particle size distribution, and a probability distribution model test of the characteristic parameters are used to revise the functional relationships between the fractal dimension D and the uniformity coefficient/curvature coefficient ( Cu/ Cc) of the grading curve. The feasibility of using D to evaluate the particle size distribution and the optimal fine grain content is then analyzed and determined. According to the results, the geometric shapes of the granular blasting materials have fractal characteristics, and their particle size distribution has a fractal distribution. The ranges of D where the rockfill and transition materials have a good particle size distribution are D = 2.254–2.529 and D = 2.358–2.559, corresponding to optimal fine grain content of 1.953%–11.805% and 10.268%–23.123%, respectively. Fractal dimension has a solid theoretical basis and strong practical applicability as an evaluation index for the particle size distribution of granular blasting materials.

Highlights

Earth-rockfill dams have significant advantages over other dam types and are an important component of large-scale water conservancy projects in mountainous regions.[1,2,3] Rockfill and transition materials account for the largest proportion of the dam materials
This article first analyzes the geometric shapes of granular blasting materials and performs field sieving tests of the gradation of granular materials
The revised functional relationships are proposed between D and curvature coefficient (Cu/Cc)

Summary

Introduction

Earth-rockfill dams have significant advantages over other dam types and are an important component of large-scale water conservancy projects in mountainous regions.[1,2,3] Rockfill and transition materials account for the largest proportion of the dam materials. Their particle size distribution directly influences dry density, permeability, shear strength, and other physical and compaction properties[4,5,6] and influences the quality and safety of dams. This article proposes a new method for evaluating the particle size distribution of granular blasting materials based on the fractal theory, which might provide several significant

Results

Discussion

Conclusion