Corrigendum: Effect of grain size distribution on the shear properties of sand

In the published article, there was an error in Figure 4 as published. The caption of Figure 4 in the published article is “Discrete model of 4 types of sands: (A) Gradation A; (B) Gradation A; (C) Gradation A; (D) Gradation (A).” The corrected caption of Figure 4 is “Discrete model of 4 types of sands: (A) Gradation A; (B) Gradation B; (C) Gradation C; (D) Gradation D.”