Figure 1
![Conceptual diagram showing the effect of (a) median particle size of uniform sand and (b) width of particle size distribution, on the shape of the soil-water characteristic curve (SWCC) of sand (Craig H. Benson et al. [14]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=0c1c7a8960654d03db47cf6be2f387c19b3427b602d8a6d4dfa514205312fdbc&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2
![Conceptual diagram presenting the effect of (a) the median particle size of uniform sand, and (b) the breadth of particle size distribution, on the parameters α and n (Craig H. Benson et al. [12]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=ceffdff320f2131ecf6d2bd063eb54e37a58ec63dc84fa5d9f72392d1b175ada&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3
![Typical soil water retention curve (Toll [59]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=0a7389d03d16c2ccacf5da6aad54cb54b2edb848350e1197dfbe0e1d2d4753fb&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 4
![Explanatory diagram of the drying and wetting processes in the porous network that is composed of cylinders with radius r; rm is the meniscus radius at the air-water interface (Do. [19]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=f317677d435f1948d4418fc228965d2d176905d6c95aa51e4c9a5bc647c438f4&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 5
![Schematic representation of the tensiometric method for the measurement of suction (Feia et al. [25]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=35d14827d9a6eff46ef27d17cfac762c009ca34d30488e41a804a305765c833a&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 6
![Experimental results used in this study (Feia et al. [25]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_006.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=7f6172b0dee2b898bdca9d5b95f48ba9ae0438510d33fc85437f747d857c5e4f&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
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Figure 18
![Comparison between the results obtained by the proposed model and those calculated by the law of Della and Feia [47].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a0a4e662f30ba53f8b8/j_sgem-2022-0025_fig_018.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T174150Z&X-Amz-Expires=3600&X-Amz-Signature=55c5d1f6fce8b251f6071c2cc24e1f2b6118ea08d9aa5fb4fbd31b1ac3fbc469&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Values of the parameters of the proposed model for the three types of sand_
| Sand | NEI-1 | NEI-2 | NEI-3 |
|---|---|---|---|
| Model parameters | |||
| α | 4.5 | 3.4 | 3 |
| n | 8.5 | 7.3 | 6 |
Characteristics of the materials to be analyzed_
| Sand | D50 (mm) | Cu | emin | emax | ρs(g/cm3) |
|---|---|---|---|---|---|
| Type 1 | 0.18 | 1.5 | 0.51 | 0.79 | 2.65 |
| Type 2 | 0.37 | 2.85 | 0.47 | 0.75 | 2.65 |
| Type 3 | 0.42 | 2.47 | 0.47 | 0.76 | 2.65 |
| Type 4 | 0.5 | 5 | 0.44 | 0.77 | 2.65 |
Characteristics of the used sands_
| Sand | dg50(μm) | Cu | emin | emax | ρs(t/m3) |
|---|---|---|---|---|---|
| NE34 | 206 | 1.5 | 0.557 | 0.884 | 2.65 |
| Type of sand | NEI-1 | NEI-2 | NEI-3 | ||
| Density index ID | 0.9 | 0.7 | 0.5 | ||