Thermo-mechanical pre-test analyses for the HAW test field

An important part of the ECN participation in the HAW experiment is the use of the measurements for the validation of the thermo-mechanical codes used at ECN for the assessment of the potential of a salt forma-tion as a host for radioactive waste. The validation process adopted at ECN is a stepwise approach. A summary and evaluation are given of all pre-test analyses which have been performed at ECN on the thermo-mechanical behaviour of the HAW test field. The analyses have been made with plane strain models for the pillar; axi-symmetric models for the boreholes and a 3D model for the central part of the HAW test field. The programs used are TASTE and ANSYS for the temperature analyses, and ANSYS and GOLIA-FAME for the deformation and stress analyses. The main assumptions concern the constitutive relations which are derived from the experiments in the 300m borehole in the Asse and the initial pressure in the HAW field. This pressure is 11 MPa and based on measure-ments in the 300m hole, simplified analyses if the stress state in the Asse and measurements of the convergence of the galleries of the HAW field. Results of the predictions of the deformations, temperatures and stresses during the test period of 5 years are presented for the iso-thermal and heated situation. In the presentation of the results special attention is given to the role of different modelling assumptions. One of the main conclusions is that, due to the short of length of the bore-holes, the interaction of the galleries and the boreholes dominates the entire thermo-mechanical behaviour. And, in addition to 2D models, 3D models are needed to accurately predict this interaction. 45 refs.; 127 figs.; 27 tabs