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Hata, Koji*; Nyunoya, Sumio*; Aoyagi, Kazuhei; Miyara, Nobukatsu
Doboku Gakkai Rombunshu, F1 (Tonneru Kogaku) (Internet), 77(2), p.I_29 - I_43, 2021/00
no abstracts in English
Okazaki, Yasuyuki*; Aoyagi, Kazuhei; Kumasaka, Hiroo*; Shinji, Masato*
Doboku Gakkai Rombunshu, F1 (Tonneru Kogaku) (Internet), 72(3), p.I_1 - I_15, 2016/00
In the rational tunnel support design, numerical analysis is powerful tool to know the estimation of the behavior before tunnel construction in the case of the special ground condition and limited similar construction. In order to evaluate the support structure quantitatively, it is necessary to understand the effect of the inhomogeneity of rock mass to the tunnel support stress in advance. In this study, tunnel excavation analysis considering the inhomogeneity of rock mass was carried out. The analysis results were compared with the stress measured in the tunnel support in the Horonobe underground research laboratory. As a result, it was revealed that the local stress measured in the tunnel support can be simulated by considering the inhomogeneity of rock mass stochastically. In addition, this study evaluated the effect of the inhomogeneity of rock mass to the tunnel support stress quantitatively by processing analysis results statistically.
Tsusaka, Kimikazu; Tokiwa, Tetsuya; Inagaki, Daisuke; Hatsuyama, Yoshihiro*; Koike, Masashi*; Ijiri, Yuji*
Doboku Gakkai Rombunshu, F1 (Tonneru Kogaku) (Internet), 68(2), p.40 - 54, 2012/09
Japan Atomic Energy Agency has excavating three deep shafts through soft sedimentary rock at Horonobe Underground Research Laboratory. In this paper, the author discussed rock mass behaviour induced by the 6.5 m diameter shaft sinking. They conducted geological mapping in an excavation face and boreholes digged around the shaft wall, field measurements such as convergence measurements and monitoring of rock displacements using multi-interval borehole extensometers around a shaft at around 160 m and 220 m in depths, and three-dimensional numerical analysis which models the shaft excavation procedure such as timing of installation of support elements and setting and removal of a concrete form. As a result, it was clarified that remarkablely large compressive strains occurred within about 1 m into the shaft wall since the rock mass behaviour was controlled by the concrete lining and that the behaviour would predominantly be induced by the fractures closing which opened significantly and propagated during excavation steps before the installation of a concrete lining and the directions where the strains occurred heavily depended on the fracture orientation around the shaft.
Tsusaka, Kimikazu; Inagaki, Daisuke; Hatsuyama, Yoshihiro*; Koike, Masashi*; Shimada, Tomohiro*; Ijiri, Yuji*
Doboku Gakkai Rombunshu, F1 (Tonneru Kogaku) (Internet), 68(1), p.7 - 20, 2012/05
Japan Atomic Energy Agency has excavating three deep shafts through soft sedimentary rock at Horonobe Underground Research Laboratory. In this paper, the author discussed change in stress and the stress distribution in a concrete lining and steel arch sets induced by the 6.5 m diameter shaft sinking. They conducted not only field measurements of stress in support elements at around 220 m in depth but also three-dimensional numerical analysis which models the shaft excavation procedure such as timing of installation of support elements and setting and removal of a concrete form. As a result, it was clarified that more than 10 MPa difference in circumferential stress occurred in a 2 m high and 400 mm thick concrete lining due to anisotropy of initial stress and three-dimensional effect of an excavation face. It was also found that a concrete lining gradually deformed from an original cylindrical form to an "oval salad bowl" form with the long axis pallarel to the direction of the minimum horizontal principal stress after a concrete form was removed.
