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
- 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
- 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