Effects of Cement Treatment on Water Retention Behavior and Collapse Potential of Gypseous Soils: Experimental Investigation and Prediction Models

Table 9

PTFs for predictions of SWRC.

	Range of suction values (kPa)	Equation
Saxton et al. [34]	From 0.0 to Air-entry value (AEV)		Where: ψ = suction (kPa); AEV = suction at air entry, kPa θ = water content; θ10 = water content at suction equal to10 kPa; θs = saturation water content (%S) = percentage of sand (%C) = percentage of clay; and the remaining parameters (a–v) are constant coefficients (Saxton et al. [34]; Shahnazari et al. [21])
	From AEV to 10
		From 10 to 1,500
				Zapata et al. [31] model	θ = C		Where: n = 7.5
				Vereecken et al. [47] model	ln (α) = a0+a1Sa+a2CL + a3C+a4BD; ln (n) = a5+a6Sa+a7CL + a8Sa^2		Sa: sand percentage (%); CL: clay percentage (%); BD: bulk density (kg/m^3); C: carbon content; a0–a8: constants
	Proposed modification of Vereecken et al. [47]	ln (α) = a0+a1Sa+a2CL + a3C + 0.4a4BD; ln (n) = a5+a6Sa+a7CL + a8Sa^2