Table 3 Comparison between UPV–UCS and UPV–ITS correlations from the present study and those reported in the literature.

1

CH clay

Lime + Nano-Al₂O₃

UCS = 423.03e^0.0025UPV

Present work

ITS = 77.597e^0.0016UPV

2

Sand

Portland cement + Nanosilica + PVA fiber

Fiber content = 0%

UCS = 0.011 e¹·⁴¹⁵ⱽ

Soleimani Kutanaei & Janalizadeh Choobbasti²⁷

Fiber content = 0.3%

UCS = 0.003 e¹·⁹²⁹ⱽ

Fiber content = 0.6%

UCS = 0.024 e¹·³⁹⁵ⱽ

Fiber content = 1%

UCS = 0.011 e¹·⁸²⁶ⱽ

3

Clayey soil

Nano-CaCO₃ + Carpet Waste Fibers

Fiber content = 0%

UCS = 67.62 e²·¹⁴⁴ⱽ

^21,22

Fiber content = 0.2%

UCS = 84.45 e⁰·⁹⁴⁷ⱽ

Fiber content = 0.4%

UCS = 58.43 e²·⁵¹⁰ⱽ

Fiber content = 0.6%

UCS = 69.56 e²·³⁷⁸ⱽ

4

Expansive clay (CH)

Portland cement + Nano-Al₂O₃

UCS = 45.664 e²·⁴⁰^5UPV

Azizi et al.⁵¹

ITS = 5.5134 e²·⁵⁴⁸^UPV

5

CH clay

Cement kiln dust (industrial waste) + Nano-SiO₂ + Polypropylene fibers

Unreinforced samples

UCS = 0.0377 e^0.00387 V

Pashabavandpouri et al.⁵²

Reinforced samples

UCS = 0.0505 e^0.00355 V

6

Collapsible soil

Nano-Al₂O₃

UCS = 0.1198 e¹·⁰¹¹⁹^UPV

Pirmousaei et al.⁵³

ITS = 0.0173 e⁰·⁹⁴⁹^5UPV

7

Clay

Portland cement + Nanosilica

UPV = 3 × 10⁻⁷ × UCS^2.9848

Aksu & Eskisar⁵⁴

Sand

UPV = 2 × 10⁻⁷ × UCS^3.0297

Clayey Sand

UPV = 2 × 10⁻⁸ × UCS^3.3251

8

clayey sand

Portland cement + Nano-ZnO

Curing Time = 7 days

UCS = 3.5985 UPV − 4.6693

Babaei et al.^2,3

Curing Time = 28 days

UCS = 2.3736 UPV − 2.8767

Curing Time = 90 days

UCS = 1.8468 UPV − 2.4359

9

CL clay

Natural zeolite + Nano-magnetite (Fe₃O₄)

Standard Curing Condition

UCS = 71.803e^0.0012UPV

Eshghi et al.⁵⁵

Accelerated Curing Condition

UCS = 63.56e^0.0015UPV