Euradwaste '08 - EU Bookshop - Europa

Volumetric deformation [%]
20
18
16
14
12
10
8
6
4
2
0
Specimen 288/06
Modelling
Specimen 288/25
-2
0 2 4 6 8 10 12 14 16 18 20 22 24
Axial deformation [%]
Confining pressure 0.2 MPa
Black: 3 tests under deformation rate 5E-06 1/s
Red: numerical simulation
492
Specimen 288/23
Figure 4: Evolution of volumetric deformation versus axial strain, strong dilatancy increase while
fracturing and slight increase after generation of shear bands in the dilatant domain, measured and
calculated on Na3 from the Asse mine (IfG)
3. Benchmark test
A laboratory test case has been defined to simulate EDZ formation and self-sealing by a suitable
loading procedure. The TC is performed on a large hollow cylinder (525 mm length, 280 mm diameter,
central borehole diameter 100 mm) of Asse Speisesalz consisting of rather pure halite (see
Figure 5). The axial/radial deformation, borehole convergence, borehole pressure and gas permeability
are continuously measured during the test, while the axial stress, the outer radial stress, and
the temperature are controlled.