A Technical Problem on the Ground Springs in the Seismic Analysis Model for Underground Vertical Shafts

Abstract

Underground vertical shafts are affected by the dynamic behavior of the entire surface layer during earthquakes. The simplest and most popular seismic analysis method for them is the seismic deformation method, which uses ground springs as a part of the analysis model, whereas their spring constants are difficult to be estimated. In this paper, the ground spring constants for an example underground vertical shaft are actually calculated by means of 3D-FEM analyses. And the fact is shown that the spring constants vary depending on the displacement patterns of the shaft and the ground due to the three-dimensional interaction of stress and strain in the continuum of the surrounding ground.