671017.pdf

10 100 1000

2. 
   


3. 1


4. 2


5. 3

Loading aer

wetting-drying

Loading without

wetting-drying

G F

E

D

C B

A

pnet(kPa)

(a)

10 100 1000

2. 10


3. 15


4. 20


5. 25

G

F

E

D

C

B

A

sc(kPa)

(b)

10 100 1000

0. 4


1. 6


2. 8


3. 0

G F

E

D

C

A B

Sr

pnet(kPa)

(c)

1 100

0. 3


1. 6


2. 9
   F, G
   E

D

Initial boundaries

Boundaries at point C

Scanning curves from C to E

A, B, C

sc(kPa)

Sr

(d)

Figure 6: Influence of wetting-drying cycle on isotropic compression. It is assumed here that푏^0 DR= 290kPa,푏WT^0 =30kPa,푑^0 DR=푑^0 WT= 1.0,
푆irr푟 = 0.3,훼DR= 1500kPa,훼WT= 750kPa,푟 = 7.5,푚 = 0.0115,and휀푝V,max= 0.25.

(2) Group 2: soil-water characteristic parameters—푏^0 DR,

푏WT^0 ,푑^0 DR,푑^0 WT,푆irr푟,and푐.

(3) Group 3: coupling parameters—훼DR,훼WT,푟,푚,and

휀V푝,max.

The parameters in Group 1 can be determined in the
same way as those for the modified Cam-Clay model (e.g.,
[ 40 ]). Particularly,휆and휅are determined from the results of
isotropic compression tests, while푀and퐺(or Poisson’s ratio
V) are obtained by performing the triaxial compression tests
on saturated soil.
The parameters in Group 2 can be determined, via a
curve-fitting procedure, by measuring the soil-water charac-
teristic curve for the soil experiencing wetting/drying cycles.

Parameters푏DR^0 ,푏^0 WT,푑^0 DR,푑^0 WT,and푆푟irrare determined based
on the measurement of the two boundary curves [ 47 ]. With
knowledge of the two boundary curves,푐is determined by

fitting the theoretical simulation of a primary scanning curve

with the measured one [ 18 ].

Among the parameters in Group 3,푟,푚,and휀푝V,maxcan be

determined by measuring the variation of preconsolidation

pressure with the matric suction or degree of saturation

during a drying process; parameters훼DRand훼WT,which

represent the influence of plastic deformation on the soil-

water characteristic curve, can be obtained by comparing

the soil-water characteristic curves under deformed and

undeformed conditions.

3. Model Performance

3.1. Wetting under Different Net Pressures.Figure 5shows the

simulated results of the wetting tests on an unsaturated clayey

soil under constant net pressures of 10 kPa and 100 kPa (푞=

0 kPa), respectively. The soil sample was wetted from푠푐 =

500 kPa to푠푐 =10kPa, while the net pressure remained