Interactive design for deep excavations

The paper presents the advantages of the use of interactive design, especially for construction in the rock mass. The rock mass deformability and strength characteristics are determined from the rock classification, and the characteristics of the supporting system for deep excavations is determined from rockbolt pull-out tests. This does not provide sufficient knowledge on the behavior of the rock mass and the supporting system during construction. In order to improve the safety of deep excavations in the rock mass it is very advantageous to use the interactive design, where in situ measurements of the rock mass displacements are made and compared to the design ones. If discrepancies between these displacements occur, it is possible to use contingency measures to assure the excavation stability. Back-analysis in the early excavation stages are also very helpful for the determination of the safety of the design geometry and supporting system. They also provide valuable information on the actual rock mass and supporting system characteristics.