Seismic design of long underground structures

The treatment presented in this paper is primarily design orientated. Various geometry configurations and boundary conditions are possible. The effect of soil is considered by soil springs. The embedment effect can also be appropriately included. Structural design criteria are developed. They include consideration of active, dynamic and passive soil pressures, thermal loads and relative displacements of the tunnel ends. Finally, design examples, used in a nuclear power plant facility showing the application of the criteria, are presented. It is concluded that the procedure presented yields a realistic cost-effective design. (orig.)