Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening and depth variation of rock properties

Sanada, Hiroyuki; Matsui, Hiroya ; Ogawa, Toyokazu*; Kinomura, Koji*; Aoki, Tomoyuki*; Yamamoto, Takuya*

It is important to understand EDZ in assessing performance of repository and designing of plug. It is known that it remains possible that the large-scale EDZ is generated due to strain localization from boring investigations and tunnel excavation analyses and rock properties changes with increase of depth. Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening, depth variation of rock properties and the actual construction procedure had been done in order to understand EDZ of Horonobe URL. The large-scale EDZ due to strain localization was generated around the border between Koetoi formation and Wakkanai formation. From result obtained from excavation analysis, scale of EDZ obtained from excavation analysis is from 60 cm to 120 cm. And it was estimated that seismic velocity changed by 20 percent, elastic modulus changed by 30 percent and hydraulic conductivity changed by 0.1 m/s order.