671017.pdf

0305 10 15 20 25

Interface shear displacement (mm)

0305 10 15 20 25

0

0. 5

1

1. 5

2

2. 5

3

3. 5

Vertical

displacement (mm)

Shear displacement (mm)

Shear stress (kPa)

ni=400kPa

ni=300kPa

ni= 200kPa

ni= 100kPa

− 0. 5

ni=100kPa

ni=200kPa

ni= 300kPa

ni= 400kPa

0

10

20

30

40

50

Figure 7: Test results for the interface between plate #1 and clay (applied normal stress of 100 kPa).

0305 10 15 20 25

Interface shear displacement (mm)

Shear stress (kPa)

ni=400kPa

ni=300kPa

ni= 200kPa

ni= 100kPa

0

10

20

30

40

50

0305 10 15 20 25

0

0. 5

1

1. 5

2

2. 5

3

3. 5

Vertical

displacement (mm)

− 0. (^5) Shear displacement (mm)
ni=100kPa
ni=200kPa
ni= 300kPa
ni= 400kPa
4
Figure 8: Test results for the interface between plate #2 and clay (applied normal stress of 100 kPa).
Here, [퐷푒푝] is the elastoplastic constitutive matrix;
MorchedZeghaletal.andZhouGuo-qingetal.proposed
the expression of[퐷푒푝]. To simplify the model, the associated
flowruleisappliedintheproposedmodelasfollows:

[퐷푒푝]=[퐷푒]−

[퐷푒]{푛}푇{푛}[퐷푒]

퐻+푀+{푛}[퐷푒]{푛}푇

, (4)

where퐻is the hardening parameter, while푀describes the
influence of the change in the interfacial frictional coefficient
with the stress state. In this proposed model, the interfacial
frictionalcoefficientisassumedtobeconstantduringshear
(푀=0) to perform the research on the effect of normal stress

history. The energy accumulated at the interface,푊푝,istaken

as the hardening parameter:

퐻=푊푝=∫

loading

푑휎푑휇푛+∫

loading

휎푛푖푑휇푛−∫

unloading

푑휎푑휇푛

−∫

sheering

푑휎푑휇푛−∫

sheering

푑휏푑휇푠.

(5)

During the loading, the initial energies accumulated

at the interface are ∫loading푑휎푑휇푛 and ∫loading휎푛푖푑휇푛,

and the energy released during the normal unloading is

∫unloading푑휎푑휇푛. During shearing, the energy consumed to