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Sakaki, Toshihiro*; Komatsu, Mitsuru*; Takeuchi, Ryuji
Vadose Zone Journal (Internet), 15(8), 7 Pages, 2016/08
Times Cited Count：2 Percentile：9.89(Environmental Sciences)In the Groundwater Recovery Experiment in Tunnel which is underway at the MIU, water saturation is one of the key parameters to monitor in order to understand the recovery processes. In this study, the process of saturation increase in the quasi-saturated zone where trapped discrete air phase affects saturation due to further increase in water pressure was studied. The relationship between the positive water pressure and saturation was measured by laboratory test using sands with trapped air bubbles and the effect of compression of bubbles on the changes in saturation was analyzed. The experimental results showed that the water pressure-saturation curves closely followed the relationship estimated solely based on the air bubble compression using Boyle's law. Based on this observation, a mathematical model was established to define the water pressure - saturation curve for the region where the water pressure is positive.
Lin, W.*; Hirahara, Noboru; Nishida, Kaoru*; Takahashi, Manabu*; Sakaki, Toshihiro
Nihon Suimon Kagakkai-Shi, 29(4), p.189 - 204, 1999/00
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Sakaki, Toshihiro
PNC TN7410 95-002, 45 Pages, 1995/04
It is considered that boreholes drilled from a drift cause disturbance to the surrounding hydraulic environment. In the study on the excavation disturbance, it is necessary to understand the influence of boreholes for proper evaluation of aquired data. Using the two-dimensional F.E.M. analysis, an influence of a borehole on the surrounding hydraulic environment and an effect of sealing packers are investigated preliminarily. The results are as follows. (1)Allowing groundwater to leak out from a borehole, pressure head in the vicinity decreased. (2)Placing sealing packers, the decrease in pressure head was reduced. (3)The more packers, the more effective. This report describes the detailed results and discussions of the investigation.
; ; Sakaki, Toshihiro;
PNC TN7410 94-049, 105 Pages, 1994/09
Excavation of a shaft or a horizontal drift in a rock mass probably affects the rock mass around the openings. It is necessary in the design, construction and safety assessment of underground facilities to consider the properties and extent of the EDZ (Excavation Disturbed Zone; the zone where rock properties and rock conditions have been changed due to excavation). PNC has carried out the in-situ experiments in the Tono mine and has identified the controlling factors in the generation and extent of the EDZ due to blasting. In order to evaluate dependence of the generation and extent of the EDZ on excavation method, Machine Bxcavation Effects Experiment has been started. In FY 1992, a horizontal drift for measurements (measuring drift) was excavated. A horizontal drift parallel to the measuring drift (test drift) is scheduled to be excavated by a machine in FY 1994. The investigations and numerical analysis before excavation of the test drift were carried out in FY 1993. The objectives of the investigations and numerical analysis carried out in FY 1993 are as follows: (1)to measure and evaluate the rock properties and the rock conditions around the test drift before excavation, and (2)to predict by numerical analysis the displacements and stress change during excavation of the test drift. The investigations and numerical analysis in FY 1993 consist of the following items: (1)laboratory tests to measure the compressive strength, deformation modulus, seismic wave velocity, electric resistivity, and so on, (2)in-situ tests to estimate deformability and permeability, (3)borehole wall observation, (4)measurement of the initial stress, (5)seismic tomography and resistivity tomography, and (6)numerical analysis to predict the displacements and stress change by the Finite Blement Method. This report describes the details of these investigations and numerical analysis carried out in FY 1993.
Sakaki, Toshihiro*; Sanada, Hiroyuki; Onuki, Kenji; Takeuchi, Ryuji
no journal, ,
no abstracts in English
