An Improved Predictive Model for Determining the Permeability Coefficient of Artificial Clayey Soil Based on Double T₂ Cut-Offs

Table 1

Basic properties of the three mineral powders used in this study.

Property	Materials
	Sand	Kaolinite	Montmorillonite
Atterberg limits
Plastic limit (%)	—	32.00	61.34
Liquid limit (%)	—	68.99	178.65
Plasticity index	—	36.99	117.31
Grain size distribution
Clay (%; <0.005 mm)	1.63	70.23	84.1
Silt (%; 0.005 mm–0.075 mm)	4.15	29.77	15.9
Sand (%; >0.075 mm)	94.22	0	0
Chemical composition
SiO2 (%)	98.85	57.82	66.63
Al2O3 (%)	0.57	35.24	16.07
K2O (%)	—	3.89	—
Fe2O3 (%)	0.08	1.86	6.50
CaO (%)	0.18	—	3.99
MgO (%)	—	0.37	5.32
Specific gravity	2.68	2.76	2.61
Classification	—	CH	CH