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Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei; Miyara, Nobukatsu*
Journal of Rock Mechanics and Geotechnical Engineering, 16(2), p.365 - 378, 2024/02
Excavation of underground caverns, such as mountain tunnels and energy-storage caverns, may cause the damages to the surrounding rock as a result of the stress redistribution. In this influenced zone, new cracks and discontinuities are created or propagate in the rock mass. Therefore, it is effective to measure and evaluate the acoustic emission (AE) events generated by the rocks, which is a small elastic vibration, and permeability change. The authors have developed a long-term measurement device that incorporates an optical AE (O-AE) sensor, an optical pore pressure sensor, and an optical temperature sensor in a single multi-optical measurement probe (MOP). Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste (HLW) deep geological disposal technology. In a high-level radioactive disposal project, one of the challenges is the development of methods for long-term monitoring of rock mass behavior. Therefore, in January 2014, the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center. The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation. In addition, hydraulic conductivity increased by 2 to 4 orders of magnitude. Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures. Based on this, a conceptual model is developed to represent the excavation damaged zone (EDZ), which contributes to the safe geological disposal of radioactive waste.
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
Hata, Koji*; Niunoya, Sumio*; Uyama, Masao*; Nakaoka, Kenichi*; Fukaya, Masaaki*; Aoyagi, Kazuhei; Sakurai, Akitaka; Tanai, Kenji
JAEA-Research 2020-010, 142 Pages, 2020/11
JAEA-Research-2020-010.pdf:13.74MB
JAEA-Research-2020-010-appendix(DVD-ROM).zip:149.9MB
In the geological disposal study of high-level radioactive waste, it is suggested that the excavation damaged zone (EDZ) which is created around a tunnel by the excavation will be possible to be one of the critical path of radionuclides. Especially, the progress of cracks in and around the EDZ with time affects the safety assessment of geological disposal and it is important to understand the hydraulic change due to the progress of cracks in and around EDZ. In this collaborative research, monitoring tools made by Obayashi Corporation were installed at a total of 9 locations in the three boreholes near the depth of 370 m of East Shaft at the Horonobe Underground Research Laboratory constructed in the Neogene sedimentary rock. The monitoring tool consists of one set of "optical AE sensor" for measuring of the mechanical rock mass behavior and "optical pore water pressure sensor and optical temperature sensor" for measuring of groundwater behavior. This tool was made for the purpose of selecting and analyzing of AE signal waveforms due to rock fracture during and after excavation of the target deep shaft. As a result of analyzing various measurement data including AE signal waveforms, it is able to understand the information on short-term or long-term progress of cracks in and around EDZ during and after excavation in the deep shaft. In the future, it will be possible to carry out a study that contributes to the long-term stability evaluation of EDZ in sedimentary rocks in the deep part of the Horonobe Underground Research Laboratory by evaluation based on these analytical data.
Sato, Shin*; Ono, Hirokazu; Tanai, Kenji; Yamamoto, Shuichi*; Fukaya, Masaaki*; Shimura, Tomoyuki*; Niunoya, Sumio*
Jiban Kogaku Janaru (Internet), 15(3), p.529 - 541, 2020/09
no abstracts in English
Niunoya, Sumio*; Hata, Koji*; Uyama, Masao*; Aoyagi, Kazuhei; Tanai, Kenji
Dai-47-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (Internet), p.92 - 97, 2020/01
Since underground water at the Horonobe Underground Research Laboratory site includes the dissolved gas, it is important to understand the quantitative behavior of AE signal waveform clearly and to develop the criteria of sorting technique. In this report, we tried to perform two types of laboratory tests (Small pipe test and Flat-plate test) in order to obtain detail data of AE signal wave form under two-phase flow. As the result, we could understand that there exists the relationship between the pressure breathing and AE generation, and that the diameter of pipe did not affect the AE behavior.
Ishida, Tsuyoshi*; Fujito, Wataru*; Yamashita, Hiroto*; Naoi, Makoto*; Fujii, Hirokazu*; Suzuki, Kenichiro*; Matsui, Hiroya
Rock Mechanics and Rock Engineering, 52(2), p.543 - 553, 2019/02
Times Cited Count：16 Percentile：67.51(Engineering, Geological)We pressurized and injected water in a hole drilled downward from a floor of the 500 m level gallery in MIU, central Japan. Acoustic emissions (AEs) monitored with 16 sensors in four boreholes located 1 m away from the HF hole exhibited two-dimensional distributions, which likely delineate a crack induced by the fracturing. Expansions of the regions in which AEs occurred were observed only immediately after the first and second BDs. Many AE events in other periods were distributed within the regions where AE events had already occurred. The initial motion polarities of P-waves indicate that tensile-dominant AE events occurred when the regions expanded and they were distributed primarily on the frontiers of the regions where AE events had already occurred. The experimental results suggest that increasing the injection flow rate is effective for generating new cracks in the refracturing, with the new crack expansions being induced by tensile fracturing.
Niunoya, Sumio*; Hata, Koji*; Uyama, Masao*; Aoyagi, Kazuhei; Wakasugi, Keiichiro
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.226 - 231, 2018/01
The objective of this research is to investigate the long-term hydro-mechanical behavior of rock mass around the shaft in the Horonobe Underground Research Laboratory (URL). The long-term monitoring has been carried out by optical AE sensors, optical water pressure sensors, and optical temperature sensors below 350m depth of the shaft in the Horonobe URL. From the first analytical results, it was too hard to discriminate the uncleared AE wave by using the resonant characteristic. Thus, at this time, we tried to reanalysis by using the half width of spectrum, we could discriminate it correctly as AE from the breaking of rock.
Fukaya, Masaaki*; Takeda, Nobufumi*; Miura, Norihiko*; Ishida, Tomoko*; Hata, Koji*; Uyama, Masao*; Sato, Shin*; Okuma, Fumiko*; Hayagane, Sayaka*; Matsui, Hiroya; et al.
JAEA-Technology 2016-035, 153 Pages, 2017/02
JAEA-Technology-2016-035.pdf:37.6MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) project in FY2016, detailed investigations of the (mechanical) behaviors of the plug and the rock mass around the reflood tunnel through ongoing reflood test were performed as part of (5) development of technologies for restoration and/or reduction of the excavation damage. As the result, particularly for the temperature change of the plug, its analytical results agree fairly well agree with the measurement ones. This means cracks induced by temperature stress can be prevented by the cooling countermeasure works reviewed in designing stage. In addition, for the behaviors of the plug and the bedrock boundary after reflooding the reflood tunnel, comparison between the results obtained by coupled hydro-mechanical analysis (stress-fluid coupled analysis) with the ones by several measurements, concluded that the model established based on the analysis results is generally appropriated.
Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
The objective of this research is to investigate the long-term hydro-mechanical behavior of rock mass around the shaft in the Horonobe Underground Research Laboratory (URL). The long-term monitoring has been carried out by optical AE sensors, optical water pressure sensors, and optical temperature sensors below 350m depth of the shaft in the Horonobe URL. From the measurement results, the extent of an excavation damaged zone was 1.5m within the shaft wall. After the excavation, it was observed that the unsaturated zone of the groundwater was spread more than 1.5m within the shaft wall.
Fukaya, Masaaki*; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Takeda, Nobufumi*; Miura, Norihiko*; Uyama, Masao*; Kaneda, Tsutomu*; Ueda, Tadashi*; Hara, Akira*; et al.
JAEA-Technology 2016-002, 195 Pages, 2016/03
JAEA-Technology-2016-002.pdf:46.3MBJAEA-Technology-2016-002-appendix(CD-ROM).zip:16.11MB
The researches on examination of the plug applied to the future reflood test was conducted as a part of (5) development of technologies for restoration and/on reduction of the excavation damage relating to the engineering technology in the MIU (2014), specifically focused on (1) plug examination (e.g. functions, structure and material) and the quality control methods and (2) analytical evaluation of rock mass behavior around the plug through the reflood test. As the result, specifications of the plug were determined. These specifications should be able to meet requirements for the safety structure and surrounding rock mass against predicted maximum water pressure, temperature stress and seismic force, and for controlling the groundwater inflow, ensuring the access into the reflood gallery and the penetration performance of measurement cable. Also preliminary knowledge regarding the rock mass behavior around the plug after flooding the reflood gallery by installed plug was obtained.
Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei; Fujita, Tomoo
Dai-44-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.319 - 324, 2016/01
Long-term monitoring and EDZ (Excavated Damage Zone) evaluation is carried out by this multi-optical measurement probe in the depth of 350m vertical shaft of Horonobe Underground Research Center project of the Japan Atomic Energy Agency. We have developed a multi-optical measurement probe incorporating an optical AE sensor, an optical water pressure sensor and an optical temperature sensor. Result of the measurement of AE, water pressure and temperature, it was made clear the influence of the shaft excavation. And from the source location analysis, it was found EDZ was less than 1.5m from shaft wall.
Sato, Toshinori; Mikake, Shinichiro; Miura, Norihiko*; Ishida, Tomoko*
Tonneru To Chika, 46(12), p.901 - 911, 2015/12
The Japan Atomic Energy Agency conducts studies and research associated with the excavation of underground research facility at the Mizunami Underground Research Laboratory in Mizunami City, Gifu Prefecture. The research laboratory is an underground facility consisting of two shafts and some drifts and excavation has currently extended to a depth of 500 m. One of in-situ experiments, groundwater recovery experiment to understand groundwater pressure and geochemical properties change due to groundwater flooded has been performed in the GL.-500m drift. This report contains the results of design work of concrete plug for groundwater recovery experiment. Structural analysis and thermal stress analysis were performed to check resistant ability to over 5 MPa. Measurement plan was also discussed in this report.
Fukaya, Masaaki*; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Takeda, Yoshinori*; Miura, Norihiko*; Uyama, Masao*; Kaneda, Tsutomu*; Ueda, Tadashi*; Toda, Akiko*; et al.
JAEA-Technology 2014-040, 199 Pages, 2015/03
JAEA-Technology-2014-040.pdf:37.2MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) project consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies for restoration and/or reduction of the excavation damage. The researches on engineering technology such as verification of the initial design were being conducted by using data measured during construction as a part of the second phase of the MIU plan. Examination about the plug for reflood test in the GL-500m Access/Research Gallery-North as part of the development of technologies for restoration and/or reduction of excavation damage were carried out. Specifically, Literature survey was carried out about the plug, based on the result of literature survey, examination of the design condition, design of the plug and rock stability using numerical simulation, selection of materials for major parts, and grouting for water inflow from between rock and plug, were carried out in this study.
Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Yoshinori*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.
JAEA-Technology 2014-019, 495 Pages, 2014/08
JAEA-Technology-2014-019.pdf:82.23MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) research on engineering technology deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research is mainly aimed in this study, which is categorized in (a) development of design and construction planning technologies, (b) development of construction technologies, (c) development of countermeasure technologies, and (d) development of technologies for security. In this study, the researches on engineering technology are being conducted in these four categories by using data measured during construction as a part of the second phase of the MIU plan.
Ijiri, Yuji*; Noda, Masaru*; Nobuto, Jun*; Matsui, Hiroya; Mikake, Shinichiro; Hashizume, Shigeru
JAEA-Technology 2013-047, 819 Pages, 2014/03
JAEA-Technology-2013-047-01.pdf:41.49MBJAEA-Technology-2013-047-02.pdf:25.26MB
The researches on engineering technology in the Mizunami Underground Research Laboratory plan consists of (1) research on engineering technology at a deep underground, and (2) research on engineering technology as abasis of geological disposal. The former research mainly aimed in this study are categorized in (a) development of design and construction planning technologies, (b) development of construction technology, (c) development of countermeasure technology, (d) development of technology for security. In this study, the researches on engineering technology are proceeded in these four categories by using data measured down to GL-460m during construction as a part of the second phase of the MIU plan.
Hashizume, Shigeru; Matsui, Hiroya; Horiuchi, Yasuharu; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Shibata, Chihoko*; Niunoya, Sumio*; Noda, Masaru*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.121 - 126, 2013/01
The "Mizunami Underground Research Laboratory" has been studying and developing engineering technology for deep underground applications. These applications are multifaceted and are categorized as development of design and construction planning technology, development construction technology, development countermeasure technology, and development of technology for construction and operation security. In this report, the dynamic stability of shaft and surrounding rock mass has been studied with respect to rock mass displacement and stress, the effect of using a concrete liner and excavating through faulted crystalline rock.
Ijiri, Yuji*; Noda, Masaru*; Sasakura, Takeshi*; Nobuto, Jun*; Matsui, Hiroya; Mikake, Shinichiro; Hashizume, Shigeru
JAEA-Technology 2012-018, 288 Pages, 2012/07
JAEA-Technology-2012-018.pdf:19.13MB
The researches on engineering technology in the Mizunami Underground Research Laboratory plan consists of (1) research on engineering technology at a deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research mainly aimed in this study are categorized in (a) development of design and construction planning technologies, (b) development of construction technology, (c) development of countermeasure technology, (d) development of technology for security. In this study, the researches on engineering technology are proceeded in these four categories by using data measured down to GL-300m during construction as a part of the second phase of the MIU plan.
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.
