Montpellier - October 22-25, 2012 5 th International meeting IN SITU HEATING TEST IN CALLOVO-OXFORDIAN CLAYSTONE: MEASUREMENT AND INTERPRETATION Conil N. 1* , Armand G. 1 , Garitte 2 B., Jobmann 3 M., Jellouli 4 M., Filippi 5 M., De La Vaissière, R. 1 , Morel 1 , J. 1. Andra, Centre de Meuse/Haute-Marne, Route Départementale 960F. 55290 Bure, France 2.Technical University of Catalonia, Barcelona, Spain 3.DBE TECHNOLOGY GmbH, Eschenstraße 55, 31224 Peine, Germany 4. ISL, 75 bd Mac Donald 75019 Paris, France 5.CEA, Centre de Saclay, 91191 Gif-sur-Yvette cedex, France To study the thermo -hydro-mechanical effects of the early thermal phase on the clay host rock of a deep repository, Andra has performed a new in-situ heating test called TED experiment. This experi- ment is the second one being carried out in the Meuse/Haute-Marne Underground Research Labora- tory The aim of the TED experiment is to measure the evolution of the temperature; deformation and pore pressure fields around several heaters and to backanalyse the thermo-hydro-mechanical proper- ties of the rock. The TED experiment was also designed to estimate the overpressure generated by heat in the zero flux plan between several heaters and to study the evolution of the damaged zone due to heat. Analysis of the experimental results will help in calibrating numerical models which will be ap- plied to the disposal cell cases. The test set-up consists of three boreholes containing the heaters and twenty one instrumented obser- vation boreholes. Each heater is 4 m long and may generate a power of 1500 W. The distance between each heater is about 2.6 m, which is close to the ratio of the disposal cell geometry concept. The sur- rounding boreholes were strategically located to follow the anisotropic THM behavior of the clay- stone. There are twelve pore pressure measurement boreholes (a total of eighteen piezometers), nine temperature measurement boreholes (108 temperature sensors) and 2 strain measurement boreholes. In order to optimize the inverse problem analysis, special attention has been paid to the reduction of un- certainties regarding the sensors location in the boreholes. Possible sensors location errors were indeed found to be a problematic issue for analysis and parameter determination in the previous thermal ex- periment ([1]). The central heater was activated on January 25, 2010 starting with a relatively low heating power of 150 W, then the heating power was increased to 300W and finally to 600 W. Each step was about four months long. After one year the two surrounding heaters were activated and the same heating load was applied. Before each heating step, permeability tests were performed in all pressure measurement boreholes in order to investigate the impact of heat on the rock permeability. After two years of heating, the measurements of the temperature field provide clear evidence of ther- mal anisotropy. The pore pressures measured (Figure 1) also confirm the anisotropy of permeability and stiffness. The in situ permeability measurements do not show any changes as a function of tem- perature. The correlation between the measured temperature and pore pressure and the results obtained by modeling is very good ([2], [3], [4], [5]). * Corresponding author O/03A/1KP 68