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Matsui, Hiroya; Mizuno, Takashi; Sasamoto, Hiroshi; Sugihara, Kozo; Yui, Mikazu
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.179 - 184, 2012/01
Japan Atomic Energy Agency has been conducted a contract study with METI (Ministry of Economy, Trade and Industry) called "The project for Grouting Technology Development" since 2008. As a part of the study, the monitoring of groundwater chemistry in a pre-grouted area has been carried out for three and half years after pre-grouting in Mizunami URL. The results suggested that the chemical compositions in groundwater affected by pre-grouting was recovered and the period to recover is evaluated about two years around an underground opening.
Tanno, Takeo; Sato, Toshinori; Matsui, Hiroya; Sanada, Hiroyuki; Kumasaka, Hiroo*; Tada, Hiroyuki*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.185 - 190, 2012/01
The Japan Atomic Energy Agency (JAEA) is conducting the MIzunami Underground research laboratory (MIU) project in order to develop comprehensive geological investigation and engineering techniques for deep underground applications (e.g. geological disposal of HLW). This modelling study has a two-fold objective, to contribute to the evaluation of the mechanical stability of shaft and research drifts, and to plan the future studies. A crack tensor model, a method of an equivalent continuum model, has been studied at the MIU. In this study, the relationship between the estimated crack tensor parameters and the rock mass classification was revealed.
Noda, Masaru*; Sato, Shin*; Niunoya, Sumio*; Hata, Koji*; Matsui, Hiroya; Mikake, Shinichiro
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.202 - 207, 2012/01
The main shaft of Mizunami URL is located in fault, and due to the geology hydrological anisotropy is observed. Lining deformation may cause by increase of lining stress with degradation of drain material or aquifer of changes in future. Therefore, study on evaluation method to predict the effect by water pressure change is needed. In this study, by implementing coupled hydraulic and mechanical analyses, validity of methods of analysis is considered as compared to measuring for hydrological anisotropy in the main shaft. According to the result of the study, water pressure dependency was not shown, but the main shaft behavior was simulated taking account of hydrological anisotropy. Also validity of methods of coupled hydraulic and mechanical analyses as deterioration prediction was confirmed.
Sato, Shin*; Noda, Masaru*; Niunoya, Sumio*; Hata, Koji*; Matsui, Hiroya; Mikake, Shinichiro
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.208 - 213, 2012/01
Creep phenomenon is one of the long-term rock behaviors. Variable compliance type mode is a representation of the phenomenon. In many of rock-creep studies, model and parameter have been verified in 2D analysis using model parameter acquired by uniaxial compression test etc considering rock types. Therefore, in this study model parameter was set by uniaxial compression test with classified rock samples which was taken from pilot boring when the main shaft was constructed. Then, comparison between measured value and 3D excavation analysis with identified parameter was made. By and large, the study showed that validity of identification methodology of parameter to identify reproduction of measured value and analysis method.
Niunoya, Sumio*; Matsui, Hiroya; Mikake, Shinichiro; Sato, Shin*; Noda, Masaru*; Hata, Koji*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.214 - 219, 2012/01
In the Mizunami URL of Japan Atomic Energy Agency (JAEA), the study on engineering technology are on going. In this study, we tried to estimate the static elastic modulus from RMR (Rock Mass Rating) based on the results of laboratory test, core observation of the pilot borehole and geological survey on the shaft wall of main shaft in the URL. The static elastic modulus based on PS logging in a borehole as well. Then, the three dimensional numerical analysis using of these parameters carried out for the validity of the examination. The results show that the RMR may be applicable to estimate the mechanical parameters of strongly weathered rock mass which is widely distributed in Japan.
Maekawa, Keisuke; Osada, Masahiko*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.53 - 58, 2012/01
It has been known that the rock material properties would be different from the condition before excavation due to air-ventilation into the shaft. The phenomena would be significant to assess a long-term geological disposal safety. But any methodologies to understand the effect have not been established yet. This paper shows the results of rock tests for engineering properties including drying-induced deformation experiment as one part of establishing research and assessment methodologies of the sedimentary rock material properties. As a result we show the tendency of drying-induced deformation of diatomaceous mudstone and the significant points of rock tests for engineering properties.
Nakanishi, Tatsuro; Fujita, Tomoo; Tsuda, Hidenori; Tanaka, Tatsuya*; Uyama, Masao*; Onishi, Yuzo*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.71 - 76, 2012/01
Grouting technology is fundamental to the safe and efficient construction of underground facilities for the geological disposal of high level waste in Japan. The Japan Atomic Energy Agency has been developing grouting materials and technologies with consideration to the long term chemical interactions between the grout material and the natural barrier rock mass. An in-situ grout injection test has been carried out at the Grimsel Test Site to optimize grouting design.
Koyama, Tomofumi*; Katayama, Tatsuo*; Hasui, Akinori*; Tanaka, Tatsuya*; Kishi, Hirokazu; Onishi, Yuzo*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.83 - 88, 2012/01
In this study, to simulate the grout injection process, the 3-D numerical model based on equivalent continuum approach was developed. The viscosity measurements for silica sol was performed to measure the time-dependent viscosity. The developed numerical model was applied to the planned in-situ grout injection tests at Grimsel test site (GTS), Switzerland. The rock type is fractured granite and the equivalent porous media was created from the DFN (Discrete Fracture Network) based on the frature data obtained from the observation boreholes. The preliminary simulation was carried out to determine the suitable grout injection pressure and investigate the arrival distance of grout from injection boreholes.
Tanaka, Tatsuya*; Bruines, P.*; Abumi, Kensho*; Hashimoto, Shuji*; Kuzuha, Yuji; Onishi, Yuzo*
Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.77 - 82, 2012/01
This study aims to establish grouting techniques and evaluation of the effects of grouting in the geological environment of crystalline rock. A hydrogeological model has been generated using discrete fracture networks based on the data obtained by the short-borehole investigation campaign performed at at Grimsel test site in Switzerland to support the design of planned in-situ grouting test. The equivalent porous media with the consideration of hydraulic heterogeneity has been created from the DFN (Discrete Fracture Network) in order to be provided for the simulation of the grout injection process. Uncertainties and remaining issues associated with the assumption in interpreting the data and its modeling were addressed in a systematic way.
Otsu, Hiroyasu*; Okawa, Junnosuke*; Takeuchi, Ryuji; Saegusa, Hiromitsu; Ota, Yasutaka*
no journal, ,
This study focused on the meaning of geological investigations on the geological risk, focusing on the risk caused by water inrush into underground structures such as tunnels/shafts constructed in discontinuous rock masses. In detail, water inrush evaluation using Discrete Fracture Network Model has been conducted focusing on what kind of geological investigation contributes to mitigation of losses due to geological risk. As a result, it is pointed out that it becomes possible to reduce a geological risk by accumulation of the further geological investigation although the risk increases temporarily by some geological investigation.