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Onoe, Hironori; Kimura, Hitoshi*
JAEA-Research 2019-001, 57 Pages, 2019/08
JAEA-Research-2019-001.pdf:10.03MB
In this study, predictive simulations were conducted in order to understand recovery behavior of groundwater environment during groundwater filling test and underground facility closure. As a result of predictive simulations of groundwater filling test, difference of groundwater environment changes around the closure test drift according to groundwater filling volume was confirmed quantitatively. As a result of the simulations, groundwater environment changes at 10 years after underground facility closure could be estimated. And, it was shown that up-corning of deep saline water through drift and shaft was occurred if hydraulic conductivity of backfill material is higher than host rock.
Matsui, Hiroya; Mikake, Shinichiro; Ikeda, Koki; Tsutsue, Jun
Dai-46-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.286 - 291, 2019/01
Japan Nuclear Energy Agency (JAEA) has been conducting the groundwater recovery experiment to develop a methodology to estimate the geological environment recovery after closure of the drift at GL-500m in Mizunami Underground Research Laboratory, Japan. For the experiment, an impervious concrete plug was constructed to maintain a recovered water pressure and its functions were assessed based on the monitoring results and interpretation of several kinds of measurements performed inside and outside of the plug during groundwater recovery test. This report summarized the change of the condition of the plug due to groundwater recovery estimated based on the different kinds of monitoring data.
Ozaki, Yusuke; Ishibashi, Masayuki; Matsushita, Tomoaki*; Masumoto, Kazuhiko*; Imasato, Takehiko*
Proceedings of 13th SEGJ International Symposium (USB Flash Drive), 4 Pages, 2018/11
In the Mizunami Underground Research Laboratory, Groundwater REcoverty Experiment in Tunnel (GREET) is performed to understanding the recovery process of geological environment after the closure of drift. In this experiment, we performed 2D electrical resistivity surveys three times. First survey was performed before the closure of test drift. Second and third surveys were performed after the closure test. The first survey detected two layers conformation that consists of conductive and resistive zones at shallower and deeper part from the drift surface, respectively. These layers correspond to the shotcrete and host rock, respectively. Second and third measurements show that the conductive zone expanded to deeper resistive part while the shallower conductive part did not change. We concluded that we captured the saturation process of dried fractures near the drift wall by closure of drift as an electrical resistivity response.
Takayasu, Kentaro; Onuki, Kenji*; Kawamoto, Koji*; Takayama, Yusuke; Mikake, Shinichiro; Sato, Toshinori; Onoe, Hironori; Takeuchi, Ryuji
JAEA-Technology 2017-011, 61 Pages, 2017/06
JAEA-Technology-2017-011.pdf:9.15MB
The Groundwater REcovery Experiment in Tunnel (GREET) was put into effect as development of drift backfilling technologies. This test was conducted by making the Closure Test Drift (CTD) recovered with water after carrying out a plug around 40m distance from northern edge face of horizontal tunnel of depth 500m, for the purpose of investigation of recovering process of rock mass and groundwater under the influence of excavation of tunnel. This report presents the efforts of backfilling investigation using bentonite composite soil and execution of backfilling into borehole pits excavated in the CTD which were carried out in fiscal 2014 as a part of GREET, and succeeding observation results inside pits from September 2014 to March 2016.
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.
Iwatsuki, Teruki
no journal, ,
Preliminary analysis on rock mechanical-hydraulic-chemical change around closure test drift was carried out to estimate groundwater recovery during re-flooding of drift. The result shows the amount of hydraulic recovery and alkalize of groundwater.
Iwatsuki, Teruki
no journal, ,
Current status on research and development of drift backfilling technology in Mizunami Underground Research Laboratory was summarized.
Takayasu, Kentaro; Keya, Hiromichi; Onoe, Hironori; Takeuchi, Ryuji
no journal, ,
The reflood test which fills the part of the tunnel of depth 500m with groundwater is being put into effect for the purpose of exemplification of the recovery ability of the geological environment in the bedrock which was disturbed by construction and operation of large-scale underground facilities, and development of observation and evaluation technique of geological environment recovery at The Mizunami Underground Research Laboratory (MIU). Water pressure observation devices were installed in the tunnel and in each observation section in the surrounding bedrock, and groundwater pressure change in this test was observed. Similarity of water pressure change between the tunnel and each observation section was considered by arranging observed water pressure change data as derivative plots and focusing their shapes.
Matsui, Hiroya; Mikake, Shinichiro; Sasaki, Sadao; Ikeda, Koki
no journal, ,
The poster is described the overview of the assessment of imprevious plug constructed for ground water recovery test.
Takayasu, Kentaro; Takeuchi, Ryuji; Onoe, Hironori
no journal, ,
The Groundwater REcovery Experiment in Tunnel (GREET) is conducted by making the Closure Test Drift (CTD) recovered with water at the depth of 500m. Backfilling test is conducted as a part of GREET to acquire physical property change of the backfill material. Bentonite mixture was constructed into two pits excavated 1m in depth on the floor of the CTD. Hydraulic pressure, soil pressure and moisture content were measured to grasp the groundwater saturation process and the swelling process of backfill material. The moisture content in the pits got almost fully saturated till one month after. During water filling event, both hydraulic pressure and soil pressure reached 3.1 MPa at maximum. The swelling pressure of the backfill was calculated as 0.03-0.09 MPa. Observation inside the pit will be continued, and characteristics of backfill material will be investigated again. Changes of hydraulic pressure and soil pressure will be simulated and the construction method will be validated.
Takeuchi, Ryuji
no journal, ,
no abstracts in English
Matsui, Hiroya; Ozaki, Yusuke; Uyama, Masao*; Fujii, Hirokazu*
no journal, ,
no abstracts in English
Watanabe, Yusuke; Hayashida, Kazuki; Murakami, Hiroaki; Iwatsuki, Teruki
no journal, ,
In assessing the safety of geological disposal of high-level radioactive waste, groundwater chemistry is an important factor influencing the performance of engineered materials and the behavior of radionuclides. It is essential to understand the hydrochemical changing process and stable condition after the closure of the disposal facilities. In this study, a simulated experimental drift was constructed in granite at a depth of 500 m at the Mizunami Underground Research Laboratory, and the hydrochemical condition and related processes after drift closure were observed.
Matsui, Hiroya; Ishiyama, Koji*; Yoshino, Osamu*; Hikima, Ryoichi*; Sanoki, Satoru*; Hayashi, Kunihiko*; Takahashi, Masahiro*; Sato, Masaru*
no journal, ,
This paper is described about the results of collaboration study between Nishimatsu cop. and JAEA to estimate the applicability of high resolution elastic wave velocity measurement for understanding of a groundwater flow. The measurement was carried out in the vicinity of the groundwater recovery test drift in MIU and it continued for about three month from just after starting at the drainage of the test drift. The results suggested that the elastic wave velocity change were measured with groundwater flow due to drainage of the test drift and the high resolution elastic wave velocity measurement can be applicable for understanding of groundwater flow.