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Miura, Yasufumi*; Suzuki, Kenji*; Morooka, Satoshi; Shobu, Takahisa
Quantum Beam Science (Internet), 8(1), p.1_1 - 1_14, 2024/03
Hirano, Tatsumi*; Maeda, Takehiro*; Murata, Tetsuyuki*; Yamaki, Takahiro*; Matsubara, Eiichiro*; Shobu, Takahisa; Shiro, Ayumi*; Yasuda, Ryo*; Takamatsu, Daiko*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(1), p.49 - 57, 2023/02
Aoyagi, Kazuhei; Sakurai, Akitaka; Miyara, Nobukatsu; Sugita, Yutaka
JAEA-Research 2020-004, 68 Pages, 2020/06
JAEA-Research-2020-004.pdf:6.4MB
JAEA-Research-2020-004-appendix1(DVD-ROM).zip:636.84MBJAEA-Research-2020-004-appendix2(DVD-ROM).zip:457.72MBJAEA-Research-2020-004-appendix3(DVD-ROM).zip:595.19MB
In construction and operational phase of a high-level radioactive waste disposal project, it is necessary to monitor on mechanical stability of underground facility for long term. In this research, we measured the displacement of the rock around the gallery and the stress acting on support materials. Furthermore, we investigated the durability of measurement sensor installed in the rock mass and the support material such as concreate lining and steel support. As a result, optical fiber sensor is appropriate for measurement of the displacement of rock mass around the gallery, while it is enough to apply the conventional electric sensor for the measurement of stress acting on the support material in the geological environment (soft rock and low inflow). The result of the measurement in the fault zone in 350 m gallery, show that the stresses acting on both shotcrete and steel arch lib exceeded the value which will cause the instability of the gallery. However, as, we found no crack on the surface of the shotcrete. By observation on the surface of shotcrete, thus, it was concluded that careful observation of shotcrete around that section in addition to the monitoring the measured stress was necessary to continue. In other measurement sections, there was no risk for the instability of the gallery as a result of the investigation of the measurement result.
Aoki, Tomoyuki*; Tani, Takuya*; Sakai, Kazuo*; Koga, Yoshihisa*; Aoyagi, Kazuhei; Ishii, Eiichi
JAEA-Research 2020-002, 83 Pages, 2020/06
JAEA-Research-2020-002.pdf:8.25MBJAEA-Research-2020-002-appendix(CD-ROM).zip:6.63MB
The Japan Atomic Energy Agency (JAEA) has conducted with the Horonobe Underground Research Project in Horonobe, Teshio-gun, Hokkaido for the purpose of research and development related to geological disposal technology for high-level radioactive wastes in sedimentary soft rocks. The geology around the Horonobe Underground Research Laboratory (HURL) is composed of the Koetoi diatomaceous mudstone layer and the Wakkanai siliceous layer, both of which contain a large amount of diatom fossils. Since these rocks exhibit relatively high porosity but low permeability, it is important to investigate the poro-elastic characteristics of the rock mass. For this objective, it is necessary to measure parameters based on the poro-elastic theory. However, there are few measurement results of the poro-elastic parameters for the geology around HURL, and the characteristics such as dependence on confining pressure are not clearly understood. One of the reasons is that the rocks show low permeability and the pressure control during testing is difficult. Therefore, a poro-elastic parameter measurement test was conducted on the siliceous mudstone of the Wakkanai formation to accumulate measurement results on the poro-elastic parameters and to examine the dependence of the parameters on confining pressure. As a result, some dependency of the poro-elastic parameters on confining pressure was observed. Among the measured or calculated poro-elastic parameters, the drained bulk modulus increased, while the Skempton's pressure coefficient, and the Biot-Wills coefficient in the elastic region decreased with the increase in confining pressure. The measurement results also inferred that the foliation observed in the rock specimens might impact a degree of dependency of those parameters on confining pressure.
Suzuki, Kenji*; Shobu, Takahisa
E-Journal of Advanced Maintenance (Internet), 10(4), p.9 - 17, 2019/02
In materials with an elastic anisotropy, a stress difference is generated between crystals when plastic deformation occurs, and it is known that this is deeply involved in material fracture. In this study, the residual stress for load direction in the plastically deformed material was investigated for each crystal orientation using the high-energy synchrotron radiation diffraction method. As a result, it was found that the residual stress is a tensile residual stress at an index with a high X-ray elastic constant (Young's modulus obtained for each diffraction surface) and a compressive residual stress at an index with a low X-ray elastic constant. We believe that this result will be useful for the technique of controlling the crystal orientation like the texture as improving the material strength.
Motoshima, Takayuki*; Fujita, Tomoo; Aoyagi, Kazuhei; Shirase, Mitsuyasu*; Nago, Makito*
Proceedings of 7th International Symposium on In-situ Rock Stress (RS 2016) (Internet), 9 Pages, 2016/05
Aoyagi, Kazuhei; Sakurai, Akitaka; Niunoya, Sumio*
JAEA-Data/Code 2015-012, 171 Pages, 2015/09
JAEA-Data-Code-2015-012.zip:33.31MBJAEA-Data-Code-2015-012.pdf:28.27MB
The objective of this report is to investigate the three dimensional stress state in the 250 m Niche off the West Shaft No.1 at the Horonobe Underground Research Laboratory. For the measurement, three 20.0m long boreholes were drilled. Hydraulic fracturing was applied as a stress measurement method. For the analysis, shut-in pressure of a transverse fractures, reopening pressure of longitudinal fractures and stress condition causing borehole breakouts were integrated into the equation; then stress state was calculated by inversion technique. As a result of the in situ stress state measurement around the experimental area, the orientation of the maximum principal stress was estimated to be ESE-WNW, dipping 70
from the vertical axis. The orientation of the minimum principal stress was NEN-SWS, dipping 60 from vertical axis. The orientation of the principal stresses is almost coincided with the direction of borehole breakouts and longitudinal crack induced in the boreholes. The values of the maximum and minimum principal stresses were 2.6 MPa and 2.1 MPa, respectively.
Aoyagi, Kazuhei; Sakurai, Akitaka; Niunoya, Sumio*
JAEA-Data/Code 2015-011, 182 Pages, 2015/09
JAEA-Data-Code-2015-011.pdf:33.41MBJAEA-Data-Code-2015-011-appendix(CD-ROM).zip:41.95MB
The objective of this report is to investigate the three dimensional stress state in the 250 m Niche off the South Shaft No.1 at the Horonobe Underground Research Laboratory. For the measurement, three 20.0m long boreholes were drilled. Hydraulic fracturing was applied as a stress measurement method. For the analysis, shut-in pressure of a transverse fractures, reopening pressure of longitudinal fractures and stress condition causing borehole breakouts were integrated into the equation; then stress state was calculated by inversion technique. As a result of the in situ stress state measurement around the experimental area, the orientation of the maximum principal stress is estimated to be between E-W and ENE-WSW, dipping almost horizontal direction. This result agrees well with the estimated orientation of the main principal stress, the location of the borehole wall breakouts in 10-E250-M01 and the orientation of the generated crack in 10-E250-M03. The value of the maximum principal stress was 3.97 MPa.
Kuwabara, Kazumichi; Sato, Toshinori; Sanada, Hiroyuki; Takayama, Yusuke
JAEA-Research 2015-005, 378 Pages, 2015/07
JAEA-Research-2015-005.pdf:125.5MBJAEA-Research-2015-005.zip:0.53MB
This report presents the results of following rock mechanical investigations conducted at the -500m Stage. (1) Laboratory tests using cores and block samples obtained at the -500m Stage. (2) In-situ stress measurement using Compact Conical-ended Borehole Overcoring (CCBO) method at the -500m Stage. (3) In-situ stress measurements using Differential Strain Curve Analysis(DSCA) method at the -500m Stage. (4) Development of rock mechanical model.
Suzuki, Hiroshi
Netsu Shori, 46(1), p.11 - 18, 2006/02
no abstracts in English
Suzuki, Hiroshi; Holden, T. M.*; Moriai, Atsushi; Minakawa, Nobuaki*; Morii, Yukio
Zairyo, 54(7), p.685 - 691, 2005/07
no abstracts in English
Suzuki, Hiroshi; Moriai, Atsushi; Minakawa, Nobuaki*; Morii, Yukio
Zairyo, 54(3), p.339 - 345, 2005/03
In a conventional method of a neutron stress measurement, it is required to know the stress-free lattice constant accurately. A new stress measurement method, which does not need the lattice constant of the strain-free material, was applied to evaluate the residual stress distributions in welded sample. The lattice constant distribution which was measured by using our proposed method showed an increase as close to the weld zone, and the absolute value of the lattice constant almost agreed with the lattice constant which was measured using coupons cut from welded sample. Therefore, it is possible to predict the lattice constant by using our proposed method. The residual stress distributions were evaluated by using conventional method and our proposed method. As a result, the residual stress distributions decided by our proposed method almost agreed with those measured by conventional method. This proposed method can be applied to determination of the residual stress states in the samples with the complex residual stress states.
Suzuki, Hiroshi; Minakawa, Nobuaki*; Moriai, Atsushi; Hataya, Mitsuhiko*; Morii, Yukio
Materials Science Forum, 490-491, p.245 - 250, 2005/00
In the conventional stress measurement method using neutron diffraction, it is required to measure the lattice strains of the same diffraction family in all three orthogonal directions. However, it is possibly difficult to measure the lattice strains of the same diffraction family in all three directions on the textured material, and also the lattice strains in three directions may not be measured in some reasons such as the size and the shape of the sample, etc. Moreover, in conventional method, it is required to know the accurate stress free lattice spacing d
, so that the stress measurement accuracy depends on the accuracy of d of powder or annealed samples. In this study, we proposed new stress measurement method which can determine the residual stress states by measuring the lattice strains in two or three orthogonal directions even if the measured diffraction families were different in all three directions. Furthermore, stress measurement method which can determine the internal residual stresses without using measured d was also proposed.
Akiniwa, Yoshiaki*; Tanaka, Keisuke*; Minakawa, Nobuaki; Morii, Yukio
Materials Science Research International, Special Technical Publication, 1, p.427 - 430, 2001/05
no abstracts in English
Suzuki, Hiroshi; Kusunoki, Koichi*; Kanematsu, Manabu*
no journal, ,
In the modern society, architectural and civil engineering structures such as reinforced concrete buildings require high seismic performance to minimize the risk exposed from urban earthquake hazards. In the reinforced concrete structures, the bond resistance between rebar and concrete is one important parameter for discussing the bond condition, and typically evaluated by measuring the strain distribution along the embedded rebar. In this study, the time-of-flight neutron diffraction technique was applied to the strain measurement of the rebar embedded in concrete. The three-dimensional deformation behavior of the embedded rebar including the axial and transverse strains was accurately measured under pullout loading. Furthermore, bond deterioration around the cracks in concrete and that around corroded rebar were successfully observed by measuring the strain distributions along rebar by neutron diffraction. The neutron diffraction technique is expected to be a novel strain measurement method for the rebar embedded in concrete for understanding actual phenomena on reinforced concrete structures.
Morooka, Satoshi; Kawasaki, Takuro; Harjo, S.; Nakada, Nobuo*; Tsukada, Yuki*
no journal, ,
Harjo, S.; Gong, W.; Kawasaki, Takuro; Mao, W.; Ito, Tatsuya
no journal, ,
no abstracts in English
