671017.pdf

0305 10 15 20 25

Interface shear displacement (mm)

Shear stress (kPa)

0

5

10

15

20

25

30

35

0

0305 10 15 20 25

0. 5

1

1. 5

2

2. 5

Vertical

displacement (mm)

− 0. 5 Shear displacement (mm)

Number 0

Number 1

Number 2

Number 0

Number 1

Number 2

Figure 9: Test results for an interface not experiencing normal unloading (normal stress of 100 kPa).

0 50 150 200 250 300 350

0

20

40

60

80

100

M

axim

um interfacial stren

gth (kPa)

Normal stress (kPa)

100

Number 0

Number 1

Number 2

Figure 10: The maximum shear stress versus the normal stress for
interfaces of different roughness.

do work is∫sheering푑휏푑휇푠. Meanwhile, energy continues to be

accumulated in the amount of∫sheering푑휎푑휇푛for the shear-

contractive interface but is consumed for the shear-dilatant
interface.
[퐷푒]is the elastic constitutive matrix, in which nonlinear
elasticity is used. For simplicity, the elastic moduli in the nor-
mal and tangential directions are assumed to be uncoupled:

[퐷푒]=[

퐷푛 0

0퐷푠], (6)

0 5 10 15 20 25 30

0

0. 5

1

1. 5

2

2. 5

3

Vertical

displacement (mm)

Shear displacement (mm)

Number 0

Number 1

Number 2

Figure 11: The vertical dilative displacement for interfaces of

different roughness.

where퐷푛and퐷푠are the normal and tangential moduli,

respectively, which are both influenced by the stress history

and stress state, according to Desai C. S.

Liu et al. [ 16 ] identified the loading direction vector{푛}as

{푛}=(

푑푓

√1+푑^2 푓

1

√1+푑^2 푓

). (7)

The parameter푑푓is related to the stress state and the

initial state of the interface; however, it cannot capture the

loading direction of the sawtooth interface in our large test.

Morched Zeghal and coworkers modelled the interface as