| Atomic Energy of Canada Limited's Underground Research Laboratory was built to allow study of concepts for the long-term disposal of Canada's used nuclear fuel in a deep geologic repository. In 2003, a decision was made to discontinue operation, decommission and permanently close the underground portion of this facility.;This project provided a unique opportunity to study the hydro-mechanical evolution of a full-scale shaft seal under conditions similar to those in a deep geologic repository. The Enhanced Sealing Project arose from the recognition of this opportunity, and consists of the installation and monitoring of a suite of sixty eight (68) sensors installed in the shaft seal that measure strain, temperature, total pressure, hydraulic pressure, moisture content and displacement.;This thesis provides an overview of the instrumentation and data logging techniques that have been successfully used to monitor the initial behaviour of the shaft seal in this unique underground environment.;Decommissioning includes the installation of a composite seal at the intersection of the access shaft with a hydraulically active fracture zone located at 275 m depth. The seal is 5 m in diameter and consists of two 3-m-thick concrete segments that confine a 6-m-thick in situ compacted core of blended bentonite and sand. The objective of the shaft seal installation is to limit groundwater mixing above and below the fracture zone. |
