Hydro-Mechanical Properties of an Unsaturated Frictional Material

174CHAPTER 8. NEW SWCC MODEL FOR SAND INCLUDING SCANNING CURVES
θ 2
ln θ
ln ln θ
ψ 2
ln ψ
ln ln ψ
Figure 8.2: Results from data transformation using experimental results (initial drainage, 1 st
drainage, 2 nd drainage) from drainage transient state column tests (loose specimen)
where: the parameter β0 is the maximum volumetric water content, that is commonly the
saturated volumetric water content θs and β3 is related to the minimum volumetric water
content, that is commonly the residual volumetric water content θr with θr = β0+β3 and β1, β2
are parameters. The new soil-water characteristic curve model was tested on experimental
results measured in several depth in the transient sand column test (drainage process). The
outcomes of the curve fits using the proposed model are given in Fig. 8.3 for loose specimen (see
also Fig. E.3 in Appendix E for curve fits of experimental results from dense specimen). The
Table 8.1: Constitutive parameters for the new SWCC model (calibrated against drainage
data)
Experimental results β0 β1 β2 β3 R 2
Loose specimen, drainage process
TDR/T 70 mm 39.00 −6.57 0.0146 −33.118 0.999
TDR/T 160 mm 38.66 −5.69 0.0316 −33.106 0.999
Dense specimen, drainage process
TDR/T 260 mm 36.72 −8.07 0.0015 −28.592 0.999
TDR/T 360 mm 34.21 −9.32 0.0003 −23.621 0.992