Geological Engineering Survey/Evaluation and Countermeasures for Final Disposal Site Improvement Part 1

—Mechanical Stability—

Abstract

We conducted geotechnical surveys and evaluations for the adjustment of final disposal site problems that have been identified from the perspective of safety, including risk management. There have been several landslides around this final disposal site. At this final disposal site, we carried out surveys of groundwater level, ground displacement and geophysical prospecting from the point of view of mechanical stability.
As a result, we showed that we can properly grasp the size and situation of landfilled waste with geological engineering methods. Moreover, landslides around this final disposal site are stabilized, but, if old waste from the Showa period (1975-1989) were cut out, destabilization could cause landslides. Further, the possibility exists that waste layers could also be destabilized when large earthquakes occur because there are many waste layers with high moisture content in this site. Thus, it is necessary to leave the old waste, which forms holding embankments and to drain internal water from this site.