Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Uehara, Shinichi*; Shimamoto, Toshihiko*; Kurikami, Hiroshi; Niizato, Tadafumi; Funaki, Hironori; Onishi, Yuzo*
no journal, ,
We performed permeability and porosity measurements by laboratory test under high pressure of Neogene and Quaternary sedimentary rock specimens from Horonobe area, northern Hokkaido island, Japan, and investigated the dependencies of these hydraulic properties on confining pressure and stress path. We then tried to evaluate permeability and porosity distribution as a function of the depth at this site from the measurement results and geological setting. The results indicated that the slope of permeability distribution is simulated reasonably well, which supports the applicability of this method of estimating underground hydraulic properties, but we can see some discrepancies in the value itself, which could be because of the effects of structures larger than specimen scale such as faults or fractures.
Onoe, Hironori; Saegusa, Hiromitsu; Motoshima, Takayuki*; Ijiri, Yuji*; Otsu, Hiroyasu*
no journal, ,
In the construction of deep underground facilities in a fractured rock mass, it is important to evaluate the influence of hydraulic and rock mechanical heterogeneities due to faults and joints, based on prior investigations. Risk assessment methodology using a combination of discrete fracture network model with financial engineering theory was developed considering unexpected water inrush, which is assumed to be one, if not the most significant issue for construction in fractured rock. In this study, the relationship between the amount of information due to the progress of investigations and cost variation regarding water inrush was evaluated, and a management method based on the risk assessment is discussed. The project that serves as the basis for the study is the construction of the underground facility in the Mizunami Underground Research Laboratory (MIU), which is now under construction by the Japan Atomic Energy Agency (JAEA).
Motoshima, Takayuki*; Ijiri, Yuji*; Onoe, Hironori; Saegusa, Hiromitsu; Otsu, Hiroyasu*
no journal, ,
Since the groundwater inflow into a tunnel has a large impact on a construction cost and a schedule. It is important to estimate the influences of groundwater inflow on the cost and schedule quantitatively based on prior information about hydrogeological properties. In this study, the hydrogeological structure of fractured granite distributed at the Mizunami Underground Research Laboratory was modeled by a stochastic Discrete Fracture Network, and the risk of water inrush is evaluated probabilistically based on the model. The effects of parameter value uncertainties derived from field data on the risk of water inrush were also discussed.