Large-scale finite element analyses of intersecting tunnels using PCs

Publisher Summary This chapter presents the settlement analyses of intersecting tunnels using a 3-D finite element method. The extension of underground transportation systems in urban areas often involves the construction of new tunnels above/below existing tunnels at varying angles of intersection. To ensure that the existing tunnel continues to comply with serviceability requirements, it is important to simulate the influence of construction on the behavior of the existing tunnel. Intersecting tunnels are irreducible 3-D problems—their soil-structure interaction mechanisms and stress-deformation fields can only be modeled realistically using a 3-D finite element mesh. If the surrounding soil exhibits time-dependent behavior, consolidation effects have to be incorporated into the analyses as well. The cost of 3-D finite element analyses incorporating consolidation is generally prohibitive to average practitioners in terms of run time and memory requirements.