Publications

Hydromechanical response of jointed host granitic rock during excavation of the febex tunnel

Sobolik, Steven R.; Webb, Stephen W.; Kobayashi, Akira; Chijimatsu, Masakazu

The FEBEX experiment is a coupled T-H-M test conducted at the Grimsel Test Site in Switzerland designed to study various processes occurring near a radioactive waste storage repository. The experiment uses cylindrical heaters placed along the axis of a drift to simulate the presence of radioactive waste canisters. An engineered barrier made of bentonite blocks is placed in the surrounding annular space. Several research teams performed blind predictions of changes in water pressure and flow rate induced by the excavation of the FEBEX tunnel. This report outlines two num-erical approaches to these predictions. One, the compliant joint model, captures the average response of a jointed rock mass by distributing the response of the individual joints throughout it. The other, a modified Crack tensor theory, treats the non-linear mechanical and hydraulic behavior of fractures. The difference of results between the models are discussed and compared to the actual test data. © 2004 Elsevier Ltd. All rights reserved.