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Yanagizawa, Koichi; Hayashi, Toshio*; Oinuma, Masaru*; Takemori, Makoto*; Ishikawa, Takanori*; Okaya, Tomoichi*; Nishigaki, Makoto*
Shadan Hojin Butsuri Tansa Gakkai Dai-129-Kai (Heisei-25-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.287 - 288, 2013/10
The development of instrument aimed at the measurement of radiation dose in the sediment of lakes, rivers and sea bed been carried out. The radiation level contained in the sediment at the bottom of lake and so on is anticipated to indicate the existence of locally high radiation spots where the diffused radioactive substance is accumulated in ponds, rivers and lakes by rainwater. The radiation dose measurement system this time is to measure 
-ray by dragging the detector, which is called probe, at the bottom of lakes to understand the radiation dose over wide areas. Furthermore, the measurement of resistivity value at the bottom of lakes is simultaneously dose to presume the condition of sediment.
Mikake, Shinichiro; Yoshida, Hidekazu; Koide, Kaoru; ; ; Yanagizawa, Koichi
Engineering Geology, 56(2), p.185 - 195, 2000/00
None
; ; Koide, Kaoru; Yanagizawa, Koichi
PNC TN7410 95-012, 65 Pages, 1995/05
An extensive study program has been carried out by PNC to estimate hydrogeological characteristics of deep underground in Japan. As a part of this program, groundwater flow analyses in Hokkaido were conducted. For the analyses of Hokkaido area (500 km 
400 km 10 km deep), a hydrogeological model representing topography, distribution of hydraulic conductivity was developed on the strength of information available from open literature. By the use of this model, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of finite element method. The results are as follows : (1)Distribution of piezometric head corresponds with topography in the study area. (2)Piezometric head distribution is hydrostatic below E.L.-1000 m in the study area. (3)Hydraulic gradient in the study area is less than 0.04 below E.L. -500 m. (4)Difference of boundary conditions at the shore side this model does not affect the result of the analyses.
; Umeda, Koji; Koide, Kaoru; Imai, Hisashi*; Yanagizawa, Koichi
PNC TN7410 94-029, 60 Pages, 1994/05
An extensive study program has been carried out by PNC to estimate hydrogeological characteristics of deep underground in Japan. As a part of this program, groundwater flow analyses in Northeast Japan were conducted. For the analyses of Northeast Japan area (300 500km 10 km deep), a hydrogeological model expressing topography, distribution of hydraulic conductivity was developed with information available from open literature. By the use of this model, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of finite element method. The results are as follows : (1)Distribution of piezometric head corresponds with topography in the study area. (2)Piezometric head distribution is hydrostatic below E,L. -1000 m in thc study area. (3)Hydraulic gradient in the study area is less than 0.04 below E.L. -500 m. (4)Analytical seepage points appear in principal catchment areas. (5)Difference of boundary conditions such as permeable or impermeable at the shore side of this model does not affect the results of the analyses. (6)In case of setting higher hydraulic conductivity to Holocene and Pleistocene scdimentary rocks than that to Pliocene sedimentary rocks, the results of the analysis are as same as the inverse case while discharge rate decreases.
Niimi, Ken; Osawa, Hideaki; Yanagizawa, Koichi; ; Yoshida, Hidekazu; Seo, Toshihiro;
PNC TN7410 94-022, 190 Pages, 1994/03
None
Koide, Kaoru; Yanagizawa, Koichi
PNC TN7410 93-016, 42 Pages, 1993/10
The purpose of this study is to develop estimation methods of hydrological characteristics of subsurface using regional data such as remote sensing data and topographical data in order to evaluate regional groundwater flow in Japan. This study consists of following three steps. The first step is to develop methods to extract the ground surface information. The second step is to quantify the relationship between the ground surface conditions and hydrological characteristics. And the final step is to develop estimation methods of hydrological characteristics of subsurface by using ground surface information. This paper describes the development of extraction methods on the ground surface information as the first step in our study. In this paper, topography and vegetation parameters were selected as the ground surface information which is considered relating to water balance which is one of hydrological characteristics. The study site was selected in the area (5km 5km) around the Tono uranium Mine, Central Japan. In order to extract topographic information, we developed a computer program to calculate direction and inclination of hill slopes using digital elevation map (DEM). The program was validated by comparing calculated results with measured slope data which were read from topographic map in the study site. We also examined grid intervals of DEM so that terrain in the study site can be represented appropriately. As a result, it was known that the grid interval of DEM should be less than 30m in the study site. We tried to classify forest types into three classes, a broad-leaved forest, conifer forest and mixed forest, using seasonal change of the normalized vegetation index (NVI) that was calculated from SPOT HRV data. Multi-temporal data (summer, autumn and winter) of SPOT were used to determine seasonal change of NVI of each forest type. As a result, it was definitely shown that each forest type has a different seasonal change of NVI. We ...
Nakano, Katsushi; Seo, Toshihiro; ; ; Ogata, Nobuhisa; Wakamatsu, Hisanori; Yanagizawa, Koichi
PNC TN7510 92-007, 27 Pages, 1992/07
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Yanagizawa, Koichi; Imai, Hisashi; ; Wakamatsu, Hisanori; Umeda, Koji
PNC TN7410 92-019, 68 Pages, 1992/07
Groundwater flow was analysed in the two areas of different scale situated in central Japan, in order to estimate hydrological condition existing at the deep underground in Japan. For the analysis in the Central Japan area (300 500km 10km deep), a hydrogeological model (a model expressing distribution of hydraulic conductivity) was built up with data from literature published so far. The model in the Tono area (8 7km 3km deep) which is a part of the Central Japan area, a hydrogeological model was built up with field data from the area studied. Based on these models, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of FEM. The results are as follows: (1)In the Central Japan area, distribution of piezometric head harmonizes with topography in the area. (2)In the Tono area, distribution of piezometric head in the sub-surface part is governed by local topography, while that in the deeper part is governed by underlying regional topography. (3)In both areas, vertical variation of piezometric head is rather small without the shallow part, which indicates hydrostatic distribution. (4)Hydraulic gradient is less than 0.04 in the most part below GL-500m in both areas. (5)The results of the analysis in the Central Japan area show that types of distribution of hydraulic conductivity below EL-3,000m, of relationship between saturation ratio and pressure head, and of lateral boundary condition, do not remarkably affect the flow situation.
Yanagizawa, Koichi; ; Osawa, Hideaki; Wakamatsu, Hisanori; Umeda, Koji
PNC TN7410 92-015, 67 Pages, 1992/06
This report deals with the permeability of rock mass from the ground surface to 1,000 m deep in Japan. The purpose of this study is to obtain the fundamental data in order to analyse groundwater behavior. 552 data of permeability are collected from 18 kinds of technical papers. These data, which are mostly obtained by in-situ test, are analysed from the viewpoint of rock types (granitic rocks, gabbroic rocks, rhyolitic rocks, basaltic rocks, Neogene sedimentary rocks, Pre-Neogene sedimentary rocks, limestone, metamorphic rocks, Quaternary sediments, Quaternary volcanic rocks), depth and location. From this study, it is found that the permeability of rock mass in Japan are in the order of 10
cm/sec to 10
cm/sec. The mean hydraulic conductivity is on the order of 10
cm/sec in limestone, 10
cm/sec in Quaternary deposite, and 10
cm/sec in the other kind of rocks. Hereafter wider collection of data and analyses are recommended for the comprehensive evaluation of rock permeability in Japan.
Ogata, Nobuhisa; Osawa, Hideaki; Semba, Tsuyoshi; Yanagizawa, Koichi
PNC TN7410 92-001, 48 Pages, 1992/01
In order to groundwater flow in rock formation, it is essential to make a topographic and hydrogeological models and to set up the initial and boundary conditions. Hydraulic properties are considered to be dominated by various factors of fracture (i.e. width, density, network) in the crystalline rock. Investigated was relationship between the hydraulic conductivity. which is one of important factors for evaluation of groundwater flow, and the fracture properties, using the method of multivariate analysis such as multiple regression analysis and cluster analysis. A total of 56 data on hydraulic conductivity and physical parameter were used that had been obtained from 2 boreholes drilled in the granitic rock of Tono area, Gifu, in the central Japan. The results are as follows: (1)The results of these two multivariate analysis are almost consistent. The hydraulic conductivity in the granitic rock is dominated by fracture system, such as number and width of the fracture, fissure-filling minerals. (2)The classificatory structure which obtained from the cluster analysis corresponds to that from hydraulic conductivity. Different hydraulic conductivities were distributed in each cluster that is dominated by width of open fracture, filling minerals, number of intersect and predominant direction of fractures. (3)The cluster analysis also implies that fracture properties of test sections with the similar hydraulic conductivities occasionally differ among them. Hence, the classifications is must be made based on the data of fracture properties as well as hydraulic conductivities. Future studies using sufficient number of data is necessary.
Yanagizawa, Koichi; Imai, Hisashi; ; Osawa, Hideaki;
PNC TN7410 91-013, 125 Pages, 1991/03
A hydrogeological measurement system was set up in order to understand the shaft excavation effect on groundwater flow quantitatively in the area of 300 meters square at the center of which the shaft is to be located. The meteorological and hydtological investigations have been performed, based on the data obtained by the measurement of river discharge rate, permeability tests and periodical monitoring of distribution of pore pressure. The present paper, first of all, describes the data and informations obtained from the measurement system before the excavation, secondly the handling of the data and the process for modelling of the hydrogeological structure and setting of some conditions for numerical simulation of the groundwater flow, and thirdly the examination of the model and the condition for calculation. Finally it referrs to the predictive simulation of the excavation effect on the groundwater flow for the period of the following three years. As the results of the simulated calculation based on the above model and conditions, estimations on the groundwater flow are summarized as follows: (a)Degree of decrease of pore pressure is smaller in accordance with distance from the shaft. The remarkably effected area is restricted within 100 meters during the next three years after the excavation. (b)When the excavated shaft passes through the Tsukiyoshi fault and reaches a highly permeable zone, the outflow into the shaft increases rapidly. The maximum outflow becomes up to about 30 L/min at the final stage of the excavation. (c)Decrease of the outflow into the existing shaft and drift is not distinct. However, the outflow decreases so gradually, when the excavation gets near to the final stage. Decrease of the outflow is about 2L/min. Method for the predictive analysis of groundwater flow developed in this study is required to be examined through a comparison between the results of prediction and the measurements during and after the excavation. It is ...
Imai, Hisashi; Yanagizawa, Koichi
PNC TN7410 90-026, 29 Pages, 1990/12
In order to develop the methodology and equipment for hydrogeological investigation, a study on regional groundwater flow has been carried out by PNC (Power Reactor and Nuclear Fuel Development Corporation) around the Tono area located in the southeast of Gifu prefecture, central Japan. Within this study, three kinds of analytical study concerning the three dimentional groundwater flow are being carried out; (1)Regional groundwater flow analysis in the area of 10 kilometers square with 1000 meter depth. (2)Local groundwater flow analysis around the experimental shaft to examine the effect of shaft excavation in the area of 300 meters square with 300 meter depth. (3)Also effect analysis on the groundwater flow considering the relaxation of rock mass due to the shaft excavation in the restricted small area of 20 meters with 50 meters depth. According to the above study of groundwater flow analysis, the properties of developing analytical code of TAGSAC (Three Dimentional Analysis of Groundwater Flow, Saitama University Code) using FEM method under saturated or unsaturated condition are presented by following fivefold; (1)The utility background of TAGSAC (2)The analysis examples by TAGSAC (3)The governing equation used in TAGSAC and the handling of the equation in unsaturated condition (4)The problems and improving plan for TAGSAC (5)The programme source of TAGSAC
Yoshida, Eiichi; Osawa, Hideaki; Yanagizawa, Koichi; Yamakawa, Minoru
Oyo Chishitsu, 30(3), p.131 - 142, 1989/00
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