ENGINEERING GEOLOGICAL INVESTIGATIONS AND THE APPLICATION OF ROCK MASS CLASSIFICATION APPROACH IN THE CONSTRUCTION OF NORWAY UNDERGROUND OLYMPIC STADIUM

Detailed engineering geological investigations have been carried out during the excavation of the world's largest man-made cavern. The 62-m span Ice Hockey Cavern has been constructed beneath a hillside in the city of Gjovik (Norway), for the 1994 Winter Olympics. A new geotechnical mapping technique developed at NGI (Norwegian Geotechnical Institute), which requires the measurement of many rock mechanical parameters in rather small areas was one of the key aspects of the project. Data from 35 such areas which together make up the majority of the upper part of the cavern have been collected. The rock mass classification approach (Q-system of Barton*) has been applied extensively to obtain and derive the geotechnical parameters needed for predicting the performance of the rock mass. In addition to the parameters included in the Q-system, other data concerning joint geometry, joint roughness and joint strength have been measured. The use of the mapped geological and geotechnical data in experimental and modelling studies led to predictions of cavern performance which agrees well with that observed at the time of completion (April '92).