Mechanical properties of rock joints

KARMO I - Mechanical Properties of Rock Joints
Rock Mechanics - Department of Civil and Environmental Engineering
Lauri Uotinen, Eero Korpi, Raphaël Yorke, Antoni Kopaly,
Daniil Iakovlev, Ari Hartikainen, Juha Antikainen & Mikael Rinne
Mechanical Properties of Rock Joints
KARMO I
1
KARMO II
τ
KARMO III
1
2
2
asperity
geometry
basic friction
3
3
4
4
δ
1
2
3
4
The mechanical properties of rock joints depend on the testing scale. Laboratory samples are
50…200 mm long and naturally occurring joints may be up to tens of meters long. Undisturbed
rock joints are hard to test, so the goal is to develop a method how small scale joint replica shear
tests can be used to derive the mechanical parameters of natural joints for numerical modelling.
Replicating surface geometry
using 3D technology
Shear box testing and
analysis of the results
Analysis of Scale Effect,
Geometry and Asperity
0,80
0,70
0,60
Shear stress [MPa]
0,50
0,40
0,30
0,20
0,10
0,00
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
Remaining challenges
1. Quantifying rock
joint matedness
2. Developing metrics for
measured roughness
3. Developing a bubble free
replication material
Shear displacement [mm]
1x14-2
1x15-2
1x16
1x16-2
1x17
2.5x10
2.5x11
2.5x12
2.5x13
5x6-2
5x7-2
5x7
5x7
5x8
5x9
7.5x2
7.5x3
7.5x4
7.5x5
10x1
tiny.cc/karmoi
eng.aalto.fi/en