Applicability of the seismic response analysis using multiple yield model for discontinuous rock

The stability, deformation behavior, permeability and other properties of discontinuous rocks are greatly influenced by the geometrical distribution of discontinuities in rock mass, and extremely important infrastructures such as nuclear power plants, large-scale underground excavations, long-span bridges, etc. built on or in discontinuous rock mass are also influenced by these same effects. However, a seismic analytical method such as for earthquake response, to correctly evaluate discontinuous conditions of rock mass has not been developed. This paper describes a new seismic response analytical method using the multiple yield model as a kind of FEM. The applicability of this method was verified by making comparisons between the seismographic records obtained with several underground deaths at The 2005 offshore Miyagi Prefecture Earthquake (MW=7.2) and The 2011 offshore the Pacific coast of Tohoku Earthquake (MW=9.0), both of which seismic motions were obtained at the same large and very important nuclear power plant, and the results of the response analyses using the seismic motions recorded at the deepest earth level of seismographs. The geological condition of the foundation ground is one of strongly folded hard sedimentary rocks. From this study, we have confirmed that the multiple yield model is an effective method for seismic response analysis.

► This paper describes a new seismic analysis method for discontinuous rock. ► The method is a kind of FEM introducing the multiple yield model. ► The validity of it was confirmed by the records of seismic motion at a nuclear power plant. ► The records used are the 2011 Japanese Earthquake (Mw=9.0) and others. ► The result shows that the method has adequate accuracy for practical problems.