Relationships between Shape Characteristics and Shear Strength of Sands

Abstract

In the Mohr-Coulomb criterion, the shear strength of sands is typically characterized by the internal friction angle, which depends on many factors such as grain size and distribution, the mineralogical origin of the particles, particle shape, unit weight, geological history, cementation, saturation, and overburden pressure. In this study, the empirical relationships among three particle shape indices, diŠerent fractal dimension deˆnitions, and internal friction angles were investigated. Within this context, direct shear tests were conducted on 38 diŠerent types of sands from diŠerent origins and with various grain sizes. For each type of sand, image analyses were performed toˆnd out the roundness, sphericity, regularity parameters belonging to individual grains. Additionally, several statistics of these parameters for diŠerent types of sands were determined. The results revealed that particle shape has a limited eŠect on the friction angle of sands in comparison to grain size distribution. Furthermore, it was found that decreasing regularity in particle shape caused an increase in the internal friction angle of uniform sands. Theseˆndings agree with the empirical relationship between the internal friction angle and particle shape suggested in the literature.

Microstructural analysis of sheared polydisperse polyhedral grains

“…However, along with grain size, the strength properties of the granular media are strongly linked to the shape of grains. It has been shown in both numerical and experimental studies that grain shape has a nontrivial effect upon packing and shear properties of granular materials [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. For instance, the grains presenting the more angular shapes (in opposition to rounded) do not show the highest shear strengths as one could expect.…”

Shaken and Stirred: A Comparative Study of Earthquake‐Triggered Soft‐Sediment Deformation Structures in Lake Sediments

“…However, the Plansee sediment is coarser than that of the other two carbonate‐rich lakes (Figure S10 in Supporting Information ). A coarser grain size distribution increases the friction angle and thereby the shear strength compared to finer sediment (e.g., Deganutti et al., 2019; Sezer et al., 2011). For loose soils, a higher content of fines could lead to a lower friction angle and higher cohesion values, and thus a higher cyclic shear strength (Noda & Hyodo, 2013; Wiemer et al., 2012).…”

The Effect of Moisture Content at Compaction and Grain Size Distribution on the Shear Strength of Unsaturated Soils

“…Further, soil grain size distribution predominantly affects soil shear strength compared to its grain shape [5]. Soil dry density and confining stress also positively influence shear strength [6,7].…”