Collection of measurement data in 2014 fiscal year at the Horonobe Underground Research Laboratory Project

Sakurai, Akitaka; Aoyagi, Kazuhei  

The Horonobe Underground Research Laboratory (URL) Project has being pursued by Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. The URL project consists of two major research areas, "Geoscientific Research" and "R&D on Geological Disposal Technologies", and proceeds in three overlapping phases, "Phase I: Surface-based investigations", "Phase II: Investigations during tunnel excavation" and "Phase III: Investigations in the underground facilities", over a period of around 20 years. The Phase I geoscientific research was carried out from March 2001 to March 2006 in parallel with design and execution scheme on URL facilities. In addition, identifying key issues that need to be addressed in the Phase II/III investigations was planned. At the beginning of the Phase II investigations, investigation reports related to measurement plan and observational construction program on shaft and drift excavation were published. The observational construction program summarizes the followings from the results of the Phase I investigations: measurements for safety and reasonable constructions, enhancement of shaft design and construction technologies and evaluation of appropriateness for the deep geological environment model estimated before shaft excavation. Currently, Phase III investigation related to geological disposal in underground facilities has been conducting. Also, measurement for consideration of long-term stability of the tunnel has been continued. This report summarizes the measurements data acquired at the West Shaft in 2014 fiscal year for the purpose of the basic data for carrying out the Observational Construction Program.