Influence of Rock Movement on the Stress/Strain Situation in Tunnels or Bore Holes with Radioactive Canisters Embedded in a Bentonite/Quartz Buffer Mass

摘要

The report presents the author's main ideas concerning the possible recurrence of large unexpected movements in Swedish pre-Cambrian rock and gives the theoretical basis for the calculation of stress and strain in the canisters and the buffer mass. A rough calculation shows that a sudden and large shear strain at actual depths will only occur along already existing continous weak zones in the bedrock. In situ rock investigations to find and locate weak zones are essential. Shear tests with a model shear apparatus were run with the canister embedded in 10 percent bentonite 90 percent quartz buffer mass. The least favorable theory (Meyerhof) gave high contact pressures which cause high bending momentum on the canister. The stresses can be reduced by changing the geometry of the canister. (Atomindex citation 09:363678)