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Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Fujita, Tomoo; Sugita, Yutaka; Nakama, Shigeo; Sanada, Masanori*
Doboku Gakkai Rombunshu, F2 (Chika Kukan Kenkyu) (Internet), 73(1), p.11 - 28, 2017/03
This study examined the mechanical characteristics of rock segments and backfill materials and analyzed the stability of the drift that is supported by the rock segments and gravel backfill. The results confirmed the technical aspects of the formation of the rock segments and the effectiveness of the planned efforts to further reduce the amount of cement used.
Ozaki, Yusuke; Matsui, Hiroya; Kuwabara, Kazumichi; Tada, Hiroyuki*; Sakurai, Hideyuki*; Kumasaka, Hiroo*; Goke, Mitsuo*; Kobayashi, Shinji*
JAEA-Research 2016-007, 125 Pages, 2016/06
JAEA-Research-2016-007.pdf:34.66MB
In Mizunami Underground Research Laboratory (MIU), the stress analysis of fractured rock have been performed with crack tensor model. In MIU, a reflooding test is performed at 500m stage. In this study, stress analysis of rock during submerging process of the tunnel is performed by using crack tensor model. The deformation of the rock under different water levels in the tunnel is simulated. The stress condition by high pressure due to inflow of groundwater into tunnel is also estimated. These simulation are performed under assumption that groundwater does not permeate into rock for the estimation of maximum pressure acting on the rock. The stress analysis with consideration of permeation of groundwater into rock is also conducted for the estimation of stress condition after the diffusion of water pressure in tunnel. The results of these analyses lead the conclusion that the pressure of the rock reaches the groundwater pressure near the face of tunnel when the tunnel is submerged.
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.
Takayama, Yusuke; Sato, Toshinori; Sanada, Hiroyuki; Tada, Hiroyuki*; Kumasaka, Hiroo*; Fukuda, Tsuyoshi*; Kobayashi, Shinji*
JAEA-Research 2015-003, 102 Pages, 2015/07
JAEA-Research-2015-003.pdf:20.21MB
In the rock mechanical study in the Mizunami Underground Research Laboratory Project, the development of the evaluation method for the excavation damaged zone due to excavation of shafts and research galleries is one of the important issues. In this study, three-dimensional excavation analysis is conducted. Crack tensor used in these analysis were measured using the data collected in wall surface observation in study tunnels such as the horizontal tunnels to a depth of 500 m. The results of analysis were compared with existing measurements at a depth of 500 m obtained using in-situ strain meters. The excavation analysis using crack tensor and initial stress obtained from the Phase I and Phase II were carried out to examine the influence of crack tensor and initial stress on the results of analysis.
Sanada, Hiroyuki; Sato, Toshinori; Tanno, Takeo*; Hikima, Ryoichi*; Tada, Hiroyuki*; Kumasaka, Hiroo*; Ishii, Takashi*; Sakurai, Hideyuki*
JAEA-Research 2014-006, 124 Pages, 2014/06
JAEA-Research-2014-006.pdf:11.26MB
Japan Atomic Energy Agency has been implementing the Mizunami Underground Research Laboratory (MIU) Project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques to construct a deep underground laboratory in crystalline rock. In the rock mechanical study in the MIU Project, the development of the evaluation method for the excavation damaged zone due to excavation of shafts and research galleries is one of the important issues. In this report, crack tensor was calculated using the tunnel wall mapping and rock mechanical test results in the shaft and research galleries in the MIU. Two dimension excavation analysis was conducted at the Ventilation Shaft and GL -500 m Sub Stage using the calculated crack tensor at GL -500 m. Based on calculated crack tensor at GL 500 m, validation of the crack tensor at GL -500 m estimated during Phase I was verified. Relative error of crack tensor was calculated in order to examine variation of relative error to the scale of observation areas.
Sanada, Hiroyuki; Hikima, Ryoichi; Tanno, Takeo; Sato, Toshinori; Goke, Mitsuo*; Tada, Hiroyuki*; Kumasaka, Hiroo*
Proceedings of ITA-AITES World Tunnel Congress 2013 (WTC 2013)/39th General Assembly, p.855 - 860, 2013/05
Japan Atomic Energy Agency (JAEA) has been implementing the Mizunami Underground Research Laboratory (MIU) Project for the R&D of geological disposal of High-level Radioactive Waste (HLW) in granite. The MIU Project has been divided into three overlapping phases: Surface-based Investigation Phase (Phase I), Construction Phase (Phase II), and Operation Phase (Phase III). In this paper, FEM analysis using crack tensor theory at the MIU was carried out in order to estimate deformation around the horizontal tunnel for investigations and construction during Phase III, and to confirm the validity of FEM analysis results including parameter settings using fracture information from the vertical borehole drilled during Phase I. The relationship between statistical observations on tunnel walls and pilot boreholes was used to estimate the crack tensor for the investigated area. FEM analysis in this work described the increase of stress in concrete liners due to decrease of Young's Modulus compared to Phase I. Since investigations during Phase II could effectively detected high angle fractures, which couldn't be satisfactorily detected during Phase I, the crack tensor was improved using the Phase II results. Predictions and applicability of the analysis method are to be confirmed with in situ experiments during Phase III.
Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi; Kumasaka, Hiroo*; Tada, Hiroyuki*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.109 - 113, 2013/01
The crack tensor model which is a kind of equivalent continuum model has been studied in rock mechanical investigation in the MIU. The fractured rock mass is modeled as the elastic continuum model with this crack tensor. In this study, this crack tensor based on the geological observation in the MIU project was calculated, and REV (Representative Elementary Volume) in the ventilation shaft and -300m access/research gallery was studied based on the relative error of this crack tensor. As a result, the convergence of the relative error was faster in the -300m access/research gallery than in the ventilation shaft.
Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Sanada, Masanori; Noguchi, Akira*; Kishi, Hirokazu*; Nakama, Shigeo; Fujita, Tomoo
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.133 - 138, 2013/01
The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkaline mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of tunnel supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the alternative supports planned for further reduction in cement influence was confirmed from a study result above-mentioned.
Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi; Matsui, Hiroya; Tada, Hiroyuki*; Goke, Mitsuo*; Kumasaka, Hiroo*; Ishii, Takashi*
JAEA-Research 2012-002, 86 Pages, 2012/03
JAEA-Research-2012-002.pdf:8.48MB
The Crack tensor model which is a kind of equivalent continuum model has been studied in rock mechanical investigation in the MIU. The fractured rock mass is modeled as the elastic continuum model with the crack tensor. In this study, crack tensor based on the geological observation in the MIU project was calculated, and REV (Representative Elementary Volume) in the shafts and research galleries was studied based on the relative error of the crack tensor. The correlation between the crack density, the trace length of crack and the trace of crack tensor and the rock mass classification was also studied.
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.
Hayashi, Katsuhiko; Noguchi, Akira; Kishi, Hirokazu; Kabayashi, Yasushi*; Nakama, Shigeo; Fujita, Tomoo; Naito, Morimasa; Tada, Hiroyuki*; Kumasaka, Hiroo*; Goke, Mitsuo*; et al.
JAEA-Research 2010-057, 101 Pages, 2011/03
JAEA-Research-2010-057.pdf:7.47MB
Cement-type materials that are used for supports or grouting at high-level radioactive waste disposal facilities leach into the groundwater and create a highly alkaline environment. Of concern in highly alkaline environments are the alteration of bentonite used as buffers or backfill materials, and of surrounding rock mass, and the increased uncertainty regarding the provision of performance of the disposal system over a long period of time. In this study, to reduce the quantity of cement-type materials that cause highly alkaline environments, technical feasibility of the support structure including the materials which considered the long-term performance of the HLW disposal system are discussed by using knowledge and technology accumulated in JAEA and Shimizu Construction. Moreover, based on the results, the problems remained in the application to the future HLW disposal institution are summarized.
Matsui, Hiroya; Tanno, Takeo; Hirano, Toru*; Goke, Mitsuo*; Kumasaka, Hiroo*; Tada, Hiroyuki*; Ishii, Takashi*
JAEA-Research 2010-043, 87 Pages, 2010/12
JAEA-Research-2010-043.pdf:3.99MB
The results are as follows (1) For the ventilation shaft at GL-350m, the crack tensor deformation analysis based on FY2004 work's results showed the calculated displacement was smaller than the measured displacement. A geometrical parameters of fractures in FY2004 work's result was different from one based on geological observation in the shaft. Therefore, the crack tensor of FY2004 work's results seems to be underestimated. (2) Large discontinuities with NE strike and high dipping observed in a shaft were major reason for the difference of crack tensors determined by borehole investigation from surface and geological observations in a shaft. Therefore, the crack tensor for pilot borehole investigation in a shaft was calculated as well and compared with each results. It was found that the fabric tensor is similar with it of geological observation and the vale was medium. (3) The crack tensor around GL-500m was estimated by relation of statistical quantities for fractures between GL-300m and GL-500m. Consequently, the deformation analysis based on the estimated crack tensor showed an increase in convergence and stress in the support system compared to FY2004 work's results.
Murokawa, Takamitsu*; Ito, Kazuyuki*; Yahagi, Ryoji*; Kumasaka, Hiroo*; Eguchi, Keita*; Ukai, Takaki*; Yamawaki, Hiroyuki; Sato, Toshinori
no journal, ,
no abstracts in English
Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Osada, Masahiko*; Maekawa, Keisuke
no journal, ,
no abstracts in English
Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Tada, Hiroyuki*; Hayashi, Katsuhiko; Noguchi, Akira; Kishi, Hirokazu; Nakama, Shigeo
no journal, ,
We are proposing to use the rock segment reducing the amount of the cementutious materials. In this report, we are getting young's modulus and poisson's ratio from the deformation experiment of the macadam mass, and performed a stability analysis of the gallery filled with macadam between the hostrock and the rock segment. We performed a alternating bearing test with high confirming pressure, and we estimated the Young's modulus and the poisson's ratio of the mass macadam from the result of the bearing test. After that, we performed the stability analysis of the galleries in the condition of the JAEA second report with the rock segment and the macadam. We found that the strain at the surface of the host rock is smaller than that of conventional one, and the stability of the host rock is remained, and the compressive stress in the rock segment is the half of the compressive strength of it. We considered that the rock segment support system is stable enough for the supporting system.
Tada, Hiroyuki*; Saito, Akira*; Nakaya, Atsushi*; Kumasaka, Hiroo*; Hayashi, Katsuhiko; Noguchi, Akira; Kishi, Hirokazu; Nakama, Shigeo
no journal, ,
Bending test of the segmental rings consist of staggered pieces of rocks bonded by low-pH mortar is conducted in order to identify the mechanical properties of rock segmental rings comparing with parallel arrangement. As a result, it was found that the maximum load was reached at 130 to 210 kN in the positive bending tests for staggered rock blocks, lower than 210 to 270 kN for rock blocks arranged in parallel. In the negative bending tests, on the other hand, the maximum load was reached at 30 to 40 kN, lower than a maximum load of 40 kN for the rock blocks arranged in parallel. The results thus varied. Cracks occurred along the interface between the rock block and mortar in the specimen for the blocks arranged in parallel. For the staggered rock blocks, cracks penetrated through the mortar and the rock block near the point of loading in the specimen. Thus, it was confirmed that cracking occurred in different manners.
Tada, Hiroyuki*; Saito, Akira*; Kumasaka, Hiroo*; Osada, Masahiko*; Takemura, Takato*; Maekawa, Keisuke
no journal, ,
no abstracts in English
Maekawa, Keisuke; Tada, Hiroyuki*; Saito, Akira*; Kumasaka, Hiroo*; Osada, Masahiko*; Takemura, Takato*
no journal, ,
no abstracts in English
Saito, Akira*; Nakaya, Atsushi*; Tada, Hiroyuki*; Kumasaka, Hiroo*; Kobayashi, Yasushi
no journal, ,
no abstracts in English
Tada, Hiroyuki*; Saito, Akira*; Kumasaka, Hiroo*; Osada, Masahiko*; Takemura, Takato*; Maekawa, Keisuke
no journal, ,
no abstracts in English
Kumasaka, Hiroo*; Kobayashi, Shinji*; Kosuga, Keiichi*; Okuyama, Yasuji*; Kusano, Takashi*; Kurita, Kazuaki*; Yamawaki, Hiroyuki; Sato, Toshinori
no journal, ,
Shotcreting is currently underway in the south research access tunnel 500 m underground at Mizunami Underground Research Laboratory. The use of the low alkaline super shotcrete spraying method, which makes it possible to obtain high strength and high stiffness quickly after spraying while minimizing an environmental impact, is being considered as a means of stabilizing an excavated rock surface whose condition is rapidly deteriorating. For the purpose of evaluating the applicability of the method to the shotcreting work currently in progress, a verification field test was conducted. This paper briefly reports on the test.
