Soil Saturation and Water Table Effects on Impedances at the APT Target Facility

摘要

During the conceptual design phase of the Accelerator Production of Tritium (APT), seismic issues associated with the deeply embedded target facility of the accelerator were raised. These concerns stem primarily from the proximity of the deep structure to the water table, as well as from the quality of the layered soil surrounding the target facility. In an effort to obtain a better understanding of the seismic response of such heavy and deeply embedded structure, which houses the most critical systems of the accelerator facility, the particularities of the soil-structure interaction are studied. The key goal of this exersize is to estimate the role that the soil saturation plays and to quantify the way it alters the dynamic interaction of the structure with the soil. Specifically, dynamic impedances which account for the position of the water table relative to the structure are estimated. This is achieved by treating the saturated soil as a two-phase medium that follows Biot's theory. While the adopted formulation is based on a 2-D SSI description, significant conclusions regarding the role of soil saturation and water table position relative to the structure are drawn.