Study on the effects of long-term evolution of geological environment on groundwater flow (Contract research)

Imai, Hisashi*; Yamashita, Ryo*; Shiozaki, Isao*; Urano, Kazuhiko*; Kasa, Hiroyoshi*; Maruyama, Yoshio*; Niizato, Tadafumi; Maekawa, Keisuke

JAEA-Research 2009-001, 116 Pages, 2009/03

JAEA-Research-2009-001.pdf:32.12MB

Evaluation of long-term geological evolution and its impact on groundwater flow is one of the major themes within the frame of Horonobe Underground Research Laboratory Project. For the purpose of development of a groundwater flow modeling methodology considering the effects of long-term geological evolution, following three items were studied: (1) Upgrade of SMS (Sequential Modeling System of geo-environmental evolution impact on groundwater flow) which was developed in 2006 FY; (2) Groundwater flow simulation under more realistic conditions of geological structures and hydrogeological conditions; and (3) Sensitivity study of geo-environmental evolution impacts on groundwater flow. The studies showed following suggestive results. (1) Development of a precise time step setting enabled to narrow the gaps in simulated head between time steps in which the model configuration used to deformed. (2) Several aspects have been found from studies on impact factors such as deposition on pore pressure, recharge rate and difference in density of saline groundwater. For evaluation of pore pressure induced by deposition, it is necessary to model the porosity and permeability variation considering the exceed pore pressure change. The setting of recharge rate during the Ice Age influence the characteristics of groundwater flow in coastal and hilly areas. The density of groundwater is not so influential as topological potential factors, however it is effective for the characteristics of groundwater flow in coastal area and intrusion of recharge water from ground surface. (3) The sensitivity study on faulting characteristics indicated that the two types of fault configuration and the hydraulic conductivity setting considered are not influential on the nature of groundwater flow above the depth of 500 m.

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (IV) -Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC TJ8400 2004-015, 192 Pages, 2005/02

JNC-TJ8400-2004-015.pdf:1.98MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code "COUPLYS (Coupling Analysis System)" on the Thermo-Hydro-Mechanical-Chemical (THMC) phenomena by THAMES, Dtransu and phreeqc, which are existing analysis code, is developed in this study.

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (III) -Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC TJ8400 2004-004, 625 Pages, 2004/02

JNC-TJ8400-2004-004.pdf:7.37MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code on the thermo-hydro-mechanical-chemical phenomena by THAMES, Dtransu and phreeqc, which are existing analysis code, is developed in this study. And we carried out the case analysis on the thermo-hydro-mechanical-chemical phenomena by this code.(1).Some supporting module, which includes transfer of dissolution concentration and total concentration (dissolution + precipitation concentration), was prepared as a functional expansion. And in order to treat de-gases and gases diffusion, accumulation and dilution phenomena, we have modified mass transport analysis code.(2).We have modified reactive transport module to treat ionic exchange, surface reaction and kinetic reaction in the each barrier.(3).We have prepared hydraulic conductivity module of buffer material depending on change of dry density due to chemical equilibrium (dissolution and precipitation of minerals), degradation of buffer material such as Ca-type bentonite and change of concentration of NaCl solutions. After THAMES, Dtransu, phreeqc and hydraulic conductivity module were installed in the COUPLYS, verification study was carried out to check basic function. And we have modified COUPLYS to control coupling process.(4).In order to confirm the applicability of the developed THMC analysis code, we have carried out case analysis on 1-dimensional and 3-dimensional model which including vitrified waste, over-pack, buffer material and rock in the HLW near-field.

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (II) - Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Neyama, Atsushi*; Tanaka, Yumiko*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC TJ8400 2003-032, 237 Pages, 2003/02

JNC-TJ8400-2003-032.pdf:2.5MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code on the thermo-hydro-mechanical-chemical phenomena by THAMES, Dtransu and phreeqe60, which are existing analysis code, is developed in this study. And we carried out the case analysis on the thermo-hydro-mechanical-chemical phenomena by this code.

Improvement for versatility of analytical method of groundwater flow considering a long-term evolution of geological environment

Maekawa, Keisuke; Niizato, Tadafumi; Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*

no journal, , 

no abstracts in English

Frequency distribution of hot spring boring in Japan

Nagasawa, Hirokazu; Takeda, Seiji; Kimura, Hideo; Shiozaki, Isao*

no journal, , 

no abstracts in English

The Effects of long-term evolution of geological environment on groundwater flow; A Case study on Horonobe area

Maekawa, Keisuke; Niizato, Tadafumi; Kurikami, Hiroshi; Asamori, Koichi; Imai, Hisashi*; Shiozaki, Isao*

no journal, , 

no abstracts in English

Study of long-term underground water flow system, 2; Attempt of underground water flow movement evaluation that considers climatic variation of coming of the cold period etc

Fuchiwaki, Hirotaka; Munakata, Masahiro; Kimura, Hideo; Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*

no journal, , 

It is thought that in an external factor that influences the underground flow, there is a climatic variation repeated at the cycle of the order of 100,000 years, the following phenomena are caused by this climatic variation, and it influences the underground flow. It is thought that the following phenomena are caused by this climatic variation, and it influences the underground flow. (1) Development and disappearance of glacier, (2) Change in precipitation, (3) Decrease in amount of training because of development of frozen soil, (4) Sea-level rhythms, (5) Upheaval and erosion by gaining the weight to the earth's crust according to development of river and disappearance, (6) Dilution of seawater according to glacier disappearance, etc. The analytical result and the evaluation are announced.

Synthesizing geoscientific data into a site model on a long-term evolution of the geological environments, Horonobe URL, Hokkaido

Niizato, Tadafumi; Maekawa, Keisuke; Yasue, Kenichi; Asamori, Koichi; Kurikami, Hiroshi; Imai, Hisashi*; Shiozaki, Isao*

no journal, , 

This study presents an application of a combined method based on the Data Flow Diagram (a Geosynthesis methodology developed in previous site-investigation programs, for example the NAGRA Wellenberg project in Switzerland) and the Process Diagrams (or Interaction Matrix; developed in the SKB Safety Report 97) for a sequence of field investigation and analysis activities.

Groundwater flow analysis considering long-term geological and environmental evolution; Influence estimation of hypothetical environmental fluctuation

Shiozaki, Isao*; Yamashita, Ryo*; Oyama, Takuya; Niizato, Tadafumi; Amano, Kenji; Imai, Hisashi

no journal, , 

no abstracts in English