Development of modeling methodology for hydrogeological heterogeneity of the deep fractured granite in Japan

Onoe, Hironori; Ishibashi, Masayuki*; Ozaki, Yusuke; Iwatsuki, Teruki

International Journal of Rock Mechanics and Mining Sciences, 144, p.104737_1 - 104737_14, 2021/08

https://doi.org/10.1016/j.ijrmms.2021.104737

In this study, we investigated the methodology of modeling for fractured granite around the drift at a depth of 500 m in the Mizunami Underground Laboratory, Japan as a case study. As a result, we developed the fracture modeling method to estimate not only geological parameters of fractures but also hydraulic parameters based on the reproducibility of trace length distribution of fractures. By applying this modeling method, it was possible to construct a Discrete Fracture Network (DFN) model that can accurately reproduce the statistical characteristics of fractures.

Results of single borehole hydraulic tests in the Mizunami Underground Research Laboratory Project (FY2016 - FY2019)

Onoe, Hironori; Takeuchi, Ryuji

JAEA-Data/Code 2020-011, 50 Pages, 2020/11

JAEA-Data-Code-2020-011.pdf:2.44MB
JAEA-Data-Code-2020-011-appendix(CD-ROM).zip:0.18MB

This report summarize the results of the single borehole hydraulic test carried out at the -300 m Stage and the -500 m Stage of the Mizunami Underground Research Laboratory from FY 2016 to FY 2019. The details of each test (test interval depth, geology, etc.) as well as the interpreted hydraulic parameters and analytical methods used are presented in this report. Furthermore, the previous results of the single borehole hydraulic tests carried out in the Regional Hydrogeological Study Project and the Mizunami Underground Research Laboratory Project before FY 2016 are also summarized in this report.

Study on modeling and analysis of groundwater flow with inverse analysis, 2 (Joint research)

Onoe, Hironori; Yamamoto, Shinya*; Kohashi, Akio; Ozaki, Yusuke; Sakurai, Hideyuki*; Masumoto, Kiyoshi*

JAEA-Research 2018-003, 84 Pages, 2018/06

JAEA-Research-2018-003.pdf:17.44MB

In this study, numerical experiments considered hydrogeological structures, which has high heterogeneity around the Mizunami Underground Research Laboratory and inverse analysis using in-situ data were carried out. The results showed that concentration of hydrogeological structure to be estimated and location of monitoring point is important for application of inverse analysis. Furthermore, it is concluded that inverse analysis using hydraulic response due to pumping test is effective for hydrogeological characterization.

Annual data compilation of water balance observation in the Regional Hydrogeological Study Project (RHS Project); For the fiscal year 2014

Ueno, Tetsuro; Takeuchi, Ryuji

JAEA-Data/Code 2015-032, 30 Pages, 2016/03

JAEA-Data-Code-2015-032.pdf:9.65MB
JAEA-Data-Code-2015-032-appendix(CD-ROM).zip:593.7MB

Tono Geoscience Center of Japan Atomic Energy Agency (JAEA) has carried out the subsurface water balance observation in order to estimate groundwater recharge rate for setting the upper boundary conditions on groundwater flow simulation and to obtain data for calibration of hydrogeological model. In the subsurface water balance observations, precipitation data and river flowrate have been observed in the Garaishi River and Hiyoshi River watersheds. The missing or abnormal data in the monitoring data during the fiscal year 2014 were complemented or corrected, and these data were compiled in data set. Because many data were accumulated, these observations were finished in the end of March, 2015.

Groundwater flow modeling in construction phase of the Mizunami Underground Research Laboratory project

Onoe, Hironori; Saegusa, Hiromitsu; Takeuchi, Ryuji

Doboku Gakkai Rombunshu, C (Chiken Kogaku) (Internet), 72(1), p.13 - 26, 2016/01

AA2015-0210.pdf:4.75MB

http://doi.org/10.2208/jscejge.72.13

The Japan Atomic Energy Agency is conducting the Mizunami Underground Research Laboratory (URL) project in Mizunami, Gifu, in order to establish scientific and technical basis for geological disposal of high-level radioactive waste. This paper comprehensively describes the result of groundwater flow modeling using data of hydraulic responses and hydrochemical changes due to URL construction. Technical know-how and methodology of hydrogeological monitoring and groundwater flow modeling were presented for characterization of hydraulic heterogeneities in fractured crystalline rock. Furthermore, effectivity of data acquisition of hydrochemical changes in groundwater for validation of result of groundwater flow modeling was indicated.

The Planning of future research program of underground laboratories in overseas

*; Tanai, Kenji; *

JNC TN8420 2001-007, 86 Pages, 2002/02

JNC-TN8420-2001-007.pdf:6.04MB

The objectives of this study is to identify the research issues, which are to be conducted in the future underground research laboratory, about operation and logistics systems for the planning of future research and development program. The research programs and experiments,etc. were investigated for the geological disposal projects in overseas sedimentary rocks and coastal geological environments aiming to reflect in the future underground research facility plan in Japan. In the investigation, information on the engineered-barrier performance, design and construction of underground facilities, tunnel support, transportation and emplacement, and backfilling technology, etc. were collected. Based on these informations, the purpose, the content, and the result of each investigations and tests were arranged. The strategy and the aim in the entire underground research facility, and the flow of investigations and tests, etc. were also arranged from the purpose, the relations and the sequence of each investigation and experiment, and the usage of results, etc.

Theoretical background and user's manual for the computer code on groundwater flow and radionuclide transport calculation in porous rock

*;

JNC TN8400 2001-027, 131 Pages, 2001/11

JNC-TN8400-2001-027.pdf:0.8MB

In order to document a basic manual about input data, output data, execution of computer code on groundwater flow and radionuclide transport calculation in heterogeneous porous rock, we investigated the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport which calculates water flow in three dimension, the path of moving radionuclide, and one dimensional radionuclide migration. In this report, based on above investigation we describe the geostastical background about simulating heterogeneous permeability field. And we describe construction of files, input and output data, a example of calculating of the programs which simulates heterogeneous permeability field, and calculates groundwater flow and radionuclide transport. Therefore, we can document a manual by investigating the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport calculation. And we can model heterogeneous porous rock and analyze groundwater flow and radionuclide transport by utilizing the information from this report.

Sampling of rock block for water flow calibration on LABROCK

Uchida, Masahiro; Yoshino, Naoto

JNC TN8410 2001-016, 36 Pages, 2001/05

JNC-TN8410-2001-016.pdf:1.53MB

This technical report summarizes sampling of the natural rock including conductive fracture. Hydraulic test was conducted at the target fracture prior to excavation. Objective of the sample was to reproduce same transmissivity at LABROCK by adjusting normal stress. This report was originally compiled by PNC in october, 1993.

The data analysis of the single well injection-withdraw tracer experiment using the MACRO II

*; Kanazawa, Yasuo*;

JNC TN8400 2001-012, 69 Pages, 2001/04

JNC-TN8400-2001-012.pdf:6.87MB

On understanding the radionuclide transport in natural barrier in radioactive waste isolation research, the macroscopic dispersion in heterogeneous permeability field in the underground rock is regarded as an important process. Therefore, we have conducted lots of tracer experiments by the MACRO II facility with an artificially constructed heterogeneous permeability field. In order to study the scale dependence of dispersion coefficients in case of laboratory experiments, we placed the flow cell horizontally, and conducted injection-withdraw tracer experiment with a single well. We have conducted I5 cases experiments. These cases were prepared by changing a position of single well and the injection-withdraw time. At each position we have conducted 9 cases and 6 cases experiments. In this report, we evaluated the macroscopic dispersion coefficients by the fitting of analytical solution to breakthrough curve measured by the 15 cases pumping tracer experiment. Consequently, we could evaluate the dispersion coefficients for 12 cases of 15 cases. Then, we discussed the relation between a injection-withdraw flow rate and a property of heterogeneous media and dispersion coefficient. The conclusions obtained from the results of the evaluation are summarized as follows, (1)It was found that the macroscopic dispersion coefficients tend to be increased with increase of the average radius of tracer front spread around a single well. (2)We have conducted any experiments with s single well settled at two positions. In case of that there is low permeability around a single well, we found dispersion coefficients are large. In case of that there is high permeability around a single well, we found dispersion coefficients are small. (3)In three cases that we could not evaluate because of incorrect accuracy of fitting, we have found it possible that there is some points that dispersion coefficients were strikingly small in tracer front.

Regional hydrogeological study project; Results from 1992-1999 period

Koide, Kaoru; Nakano, Katsushi; Takeuchi, Shinji; Hama, Katsuhiro; ; Ikeda, Koki;

JNC TN7400 2000-014, 83 Pages, 2000/11

JNC-TN7400-2000-014.pdf:4.84MB

The Japan Nuclear Cycle Development Institute (JNC) has been conducting a wide range of geoscientific research in order to build a firm scientific and technological basis for the research and development of geological disposal. One of the major components of the ongoing geoscientific research programme is the Regional Hydrogeological Study (RHS) project in the Tono region, central Japan. The main goal of the RHS project is to develop and demonstrate surface-based investigation methodologies to characterize geological environments at a regional scale in Japan. The RHS project was initiated in 1992. The first five years of the project were devoted mainly to develop methodologies and techniques for deep borehole investigations in crystalline rock in Japan. Investigations to verify the performance of new instruments and methods for borehole drilling, hydraulic testing and groundwater sampling were conducted. In the last four years, surface-based investigations and a stepwise development of models of the geological environment have been carried out. To date, remote sensing, geological mapping, airborne and ground geophysical investigations, and measurements in eleven deep boreholes have been carried out. Hydro monitorring is continuing in these boreholes. Important results that have been obtained from these investigations include multi-disciplinaly information about the heterogeneity of lithology and hydraulic, geochemical and rock mechanical properties of the granitic rock, and evolution of the groundwater geochemistry. Technical knowledge and experience have been accumulated, which allow application of the methodologies and techniques to characterize the geological environment in crystalline rock. The results from these R%D activities were used as prime inputs for the H12 report that JNC submitted to the Japanese Government in l999. Results from such R&D is also acknowledged by other geoscientific studies in general. JNC will synthesize the results from R&D ...