J-GLOBAL

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10064-020-02093-2

researchmap

Other Link： http://link.springer.com/article/10.1007/s10064-020-02093-2/fulltext.html

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

J-GLOBAL

researchmap

Publishing type：Research paper (scientific journal)  

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.18494/SAM.2021.3155

researchmap

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

researchmap

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

researchmap

Authorship：Lead author   Publishing type：Research paper (international conference proceedings)  

researchmap

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

researchmap

Publishing type：Research paper (scientific journal)  

researchmap

Publishing type：Research paper (international conference proceedings)  

researchmap

Publishing type：Research paper (international conference proceedings)  

researchmap

Publishing type：Research paper (scientific journal)  

researchmap

Publishing type：Research paper (scientific journal)  

researchmap

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 電気学会  

CiNii Article

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Authorship：Lead author   Language：Japanese  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

This paper describes the sensor network systems developed in cooperation with Shiojiri city. We developed a relay network for sensor networks with high robustness that continues to operate even in the event of a large-scale disaster. By making use of the technology, a relay network composed of more than 600 repeaters was built and is currently operational in Shiojiri city in the Nagano Prefecture. Additionally, by using this relay network as a test bed, we developed various applications, and have been operating them locally as well as in other areas. Based on these experiences, this paper describes the development of the information and communications technology and its outcomes obtained from building the test bed.

DOI： 10.1109/ISCAS.2019.8702078

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：公益社団法人 地盤工学会  

<p>The authors hypothesized that displacement on a model slope would not occur unless the initial quasi-saturated volumetric water content was exceeded. This prediction was based on a past experiment using a small model slope for the purpose of predicting slope failure beforehand. However, in previous experiments, the soil-layer thickness of the slope was as thin as 100 mm, so the behaviors of sensors installed at the upper, middle, and lower slopes were nearly the same. Also, the size of the model slope was small, and the characteristics of each point could not be grasped. Therefore, in this study, we verified whether the hypothesis obtained from past experimental results was valid even when the topsoil-layer thickness to 300mm and the model size are increased. The following findings were obtained. Displacement was confirmed to occur in the vicinity of the toe of the slope after the volumetric water content exceed the initial quasi-saturated volumetric water content. On the other hand, in the middle part of the slope, while still below the initial quasi-saturated volumetric water content, displacement was confirmed. Thus, depending on the installation position, the displacement may occur before the initial quasi-saturated volumetric water content is exceeded. </p>

DOI： 10.3208/jgs.13.183

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 電気学会  

<p>Real time measurement of soil pH is demanded in precision agriculture. Therefore, pH measurement capability in low water content soil was needed to confirm. In this paper, we fabricated an ISFET type pH sensor which can be inserted into soil. The sensor performed to measure two type of experiments. First, we experimented with changes in sensor output due to soil water content. The sensor output voltages were changed by changes in the soil pH value. In contrast, the voltages didn't be changed by changes in the soil water content. Secondly, we experimented whether the output of the sensor shows the same change when the soil pH changes during the measurement. The sensor could detect the pH value of soil which was changed dramatically by passing water. We confirmed that the ISFET type pH sensor can directly measure soil pH in real time.</p>

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：総合土木研究所  

CiNii Article

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

A low-leakage-current-type impedance sensor chip with shield structures has been fabricated. The low limit detection of soil-water-content measurement was improved compared with that of the other semiconductor-type sensors. The shield structures were fabricated under the impedance sensor areas. To measure the weak signal current eliminated by the leakage current, we proposed a new operation circuit to separate the leakage current. Our sensor was able to measure low water content of 10% or less. The sensor could detect the change of water content in the slope of mountain when it rained.

DOI： 10.1016/j.sna.2017.12.022

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：International Society for Rock Mechanics  

A series of laboratory slope failure experiments was conducted to elucidate the initiation of rainfall-induced slope failures from moisture content measurement records. The change in moisture content during the infiltration of rainwater and at initiation of slope failures was monitored by moisture sensors (Amplitude Domain Reflectrometry type). Prior to experiments, numerical unsteady seepage analyses were also conducted to identify the hydraulic response of the soil slope models to rainfall. The experiment results showed that slope failures were initiated by the increase in moisture content of the soil at the toe of the slope. Moisture content of the soil was noted to reach its saturated value at the time of failure. This indicates that rainfall-induced slope failure is a consequence of instability of the toe of the slope induced by saturation process under drained condition, and the major portion of the sliding mass may still be in an unsaturated condition. The experiments reported in this Paper also indicated that the direct measurements of change in moisture content could provide a great possibility in predicting the critical time of the initiation of rainfall-induced slope failures. Therefore, the results of applying any moisture sensors to predict and to monitor slope movements are encouraging.

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

A low-leakage-current type impedance sensor chip with shield structures has been fabricated. The low limit detection of soil-water-content measurement was improved compared with that of the other semiconductor type sensors. The shield structures were fabricated under the impedance sensor areas. To measure weak signal current eliminated the leakage current, we proposed a new operation circuit to separate the leakage current. Our sensor achieved to measure low water content 10 % or less.

DOI： 10.1109/TRANSDUCERS.2017.7994253

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：ジェイスパーク ; [1979]-  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publisher：地盤工学会  

CiNii Article

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOIL SCI SOC AMER  

On closure of an underground facility, recovery of the geoenvironmental conditions is one of the essential issues for ensuring proper implementation of closure. At the Mizunami Underground Research Laboratory, Gifu, Japan, a tunnel flooding test is underway in which a section of a deep underground tunnel is filled with groundwater and the existing desaturated zone with trapped air is subjected to high water pressure. Water saturation in the unsaturated zone as a function of capillary pressure is well understood. However, the process of a saturation increase due to a further increase in water pressure is less well studied. In this study, a simplified laboratory setup using test sands with trapped air was established in a pressure chamber. The relationship between the positive water pressure up to 1.5 MPa and saturation was measured and the effect of the compression of trapped air bubbles on the change in saturation was investigated. The experimental results showed that the saturation increased further from the initial saturation of about 0.85 at zero suction. Most of the saturation increase occurred up to a water pressure of 0.5 MPa, at which the saturation reached 0.98. At 1.5 MPa, the air bubbles were compressed to a non-detectable level so that the sands were fully saturated. A mathematical model was established based solely on Boyle's law to define the water retention curve in a broad sense for the domain where the water pressure is positive. The measured water pressure-saturation data closely followed the relationship estimated with the established model.

DOI： 10.2136/vzj2015.12.0165

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

To minimize the damage caused by slope failure, knowledge of the increase in water content in mountain soil is important. Our group has been studying miniaturized impedance sensor for multipoint measurements in the soil. To improve contact characteristics between sensor surface and free water in soil, SiOx film of hydrophilic property covered on our conventional sensor chip. For contact property test, the sensor chip measured impedance of model soils. The proposed sensor achieved to stable contact the free water in the soil. Moreover, the chip operated for long period of time in mountain slope. The sensor could measure nearly theoretical outputs which responded to rainfalls. We succeeded to fabricate the stably soil monitor sensor with hydrophilic film SiOx.

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

For some time, we have been working toward the "Realization of a Safe and Secure Society using ICT in Shiojiri-City, Nagano Prefecture." This is a project comprised of two phases: information gathering, and dissemination of information. For information gathering, we are developing systems to confirm the whereabouts of children and the elderly, who are vulnerable in disasters, and systems to gather information on the situation in mountainous regions, rivers etc. For dissemination of information, we are developing systems using broadcast technology for disseminating information to residents, such as disaster information and evacuation warnings derived from the gathered information. This presentation will describe the project goals, the background of the project thus far, and an overview of the developed system. The current situation and plans for the future will also be discussed.

Web of Science

researchmap

Language：Japanese   Publisher：公益社団法人 日本地下水学会  

Fluctuations in water table height tend to generate an unsaturated zone located below the water table. It is not well understood how water saturation is affected by trapped air in this unsaturated zone. In this study, water characteristic curves for primary drainage, wetting, resaturation (under the water table), and secondary drainage cycles were measured using a one-dimensional sand-filled column. It was assumed that the pore air pressure was atmospheric and that the effect of air pressure in the discrete air bubbles could be neglected. The experimental results showed that, in the resaturation cycle, the water saturation under positive water pressure increased with water pressure and exceeded that of the water table level whereas, in the secondary drainage cycle, the saturation change was rather small indicating that the water pressure – saturation relationships in resaturation and secondary drainage cycles below the water table were irreversible. Under the conditions considered in this study, the increase of water saturation in the resaturation cycle was found to be largely controlled by the upward movement of trapped air bubbles. The obtained water retention data for the secondary drainage cycle indicated that the relationships can be affected by the maximum resaturation level that the soil has experienced. This suggests that a unique definition of the secondary drainage curve may not be appropriate when the soil has experienced resaturation.

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Soil Science Society of America  

With the goal of finding empirical direct relationships between the air-entry values (AEV) and characteristic particle diameters (i.e., d 10, d20, d30, d90,) determined from the particle-size distribution, we examined the AEV values for a variety of disturbed sands. It was found that the AEVs were, in general, strongly correlated to the characteristic diameters. The correlation was more distinct for uniform sands with uniformity coefficient of 2 or smaller. For those with larger uniformity coefficient values, the AEVs were highly correlated to smaller characteristic particle sizes d10 to d50 but less with larger characteristic particle sizes, d60 to d90. For all the sands examined in this study, the AEVs showed the least scatter when plotted against d30. The large particles do not necessarily control the AEVs because the pores between the large particles are often filled with smaller particles. The following best-fit power functions with respect to the frequently used characteristic particle diameters were found to have high r2 values
AEV = 8.2 d30 -0.99and AEV =9.5 d50 -1.05(with AEV in cm and d in mm). The exponent close to -1 in both relationships confirms a strong "inverse" proportionality. The effective pore diameter, de′, estimated from the AEVs agreed closely with the mean pore diameters measured with mercury porosimetry and X-ray micro-tomography. All these findings suggest that the AEVs are strongly controlled by the particle sizes which determine the mean pore size, and that the capillary rise theory is applicable in terms of the effective pore diameter. Finally, easy-toimplement rule-of-thumb expressions, AEV [cm] = 8/d 30[mm] and AEV [cm] =10/d50[mm] were proposed with some limitations for a quick but reasonably accurate prediction of the AEV. © Soil Science Society of America.

DOI： 10.2136/sssaj2013.06.0237n

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

In order to assess the risk of CO2 leakage affecting the groundwater quality in aquifers, it is important to understand the mechanisms of CO2 gas release when brine carrying dissolved CO2 migrates to the shallow subsurface from sequestrated zones of deep geologic formations. As the brine with dissolved CO2 elevates where the water pressure is lower, development of a gas phase starts with evolution of gas out of liquid, followed by gas phase growth and movement. However, conditions under which CO2 gas evolution is triggered, how the gaseous phase CO2 migrates and/or gets entrapped in the naturally heterogeneous formations are not well understood due to the difficulties involved with obtaining detailed experimental data. In this study, our goal was to identify the conditions under which dissolved CO2 forms a gas phase and to understand how the formed CO2 gas migrates through the saturated soil formation. In particular, we put emphasis on the critical gas saturation (at which the onset of gas phase migration occurs) and how this is explained by the theoretical and modeling studies reported in the literature. We have performed a series of experiments in the laboratory using a highly instrumented long column under highly controlled conditions that are not feasible in field settings. The 4.5 m-long vertical column setup was instrumented with automated sensors to continuously monitor phase saturation, electrical conductivity (EC), temperature, and water pressure distribution along the column length as well as the rates of water and gas outflow at the upstream end of the column. The observations showed that (1) concentration of dissolved CO2 influenced the vertical extent of the gas phase formation, (2) the gas formation pattern was different if the saturation pressure was lower or higher than the static water pressure at the injection port which results largely from the gravity and viscous forces somewhat competing under the conditions in the experiments, (3) the mass transfer-dominant period where bubbles grew and water outflow increased was relatively short, (4) gas outflow was detected at the column outlet only after a continuous gas phase was formed and breakthrough had occurred, (5) the critical gas phase saturation at which the generated gas phase gets mobilized was always about 0.3-0.4 in homogeneous cases, (6) for the heterogeneous cases, a gas saturation higher than the critical gas saturation was observed due to accumulation of gas phase under a finer layer, (7) the injection rate did not affect the gas formation behavior whereas the temperature variation did, and (8) in some cases formation of gas appeared to be triggered by heterogeneities. These observations are expected to improve our understanding of gas evolution for better conceptualization and model development. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijggc.2013.03.025

Web of Science

researchmap

Language：Japanese   Publisher：公益社団法人 日本地下水学会  

The water characteristic curve is one of the important properties of soil required for the evaluation of groundwater flow in the unsaturated zone. Unsaturated zones occur below the water table when there is fluctuation of the water table depth. In such zones, it is not well understood how the trapped air behaves and how it affects water saturation. In this study, we estimated the water characteristic curves based on the water pressure and water saturation. The water saturation was monitored for wetting and re-saturation cycles where the water pressure was gradually increased up to 5.5 kPa using a one-dimensional sand-filled column. In the wetting cycle, the water characteristic curve was obtained assuming that the pore air pressure was atmospheric. In the re-saturation cycle, how the water characteristic curve would extend was estimated by neglecting the effect of air pressure in the discrete air bubbles. The experimental results showed that the water saturation under positive water pressure, i.e., below the water table, increased with water pressure and exceeded that at the water table level. It was concluded that the rate of increase of water saturation resulted not only from the discrete air bubbles being compressed but also being forced up as the water table gradually moved up. Not considering the increase in water saturation in the unsaturated zone below the water table could result in a significant underestimation of hydraulic conductivity in such a zone.

DOI： 10.5917/jagh.55.269

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

We believe it is extremely important to quickly communicate information - on matters such as the extent of the damage and the safety of affected persons - when a large-scale earthquake or other disaster occurs. However, if electric power is lost, communication will be impossible with existing information networks. For this reason, we have built an Ad-Hoc network in Shiojiri City enabling communication even if electric power is lost due to a large-scale disaster. Using this Ad-Hoc network, we are building a sensor network to forecast landslide disasters. Among the various sensors installed to the sensor terminals, this paper reports in particular on observation results with EC sensors. © 2013 Springer-Verlag.

DOI： 10.1007/978-3-642-38401-1_14

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 電気学会  

To minimize the damage caused by slope failure, knowledge of the increase in water content in mountain soil is important
however the current technology for monitoring this is insufficient. In this study, an EC sensor chip with an insulation layer with increased thickness, designed to reduce leakage current, was fabricated. Utilizing the chip, a wireless sensor terminal was constructed for long term continuous monitoring of the water content in mountain soil. The usefulness of the EC sensor for predicting slope failure was confirmed.

DOI： 10.1541/ieejsmas.133.278

Scopus

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)   Publisher：日本原子力研究開発機構  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)  

CiNii Article

researchmap

Publisher：公益社団法人 土木学会  

 Japan Atomic Energy Agency has been conducting the Horonobe Underground Research Laboratory (URL) project in Horonobe, Hokkaido, as a part of the research and development program on geological disposal of high-level radioactive waste. Pore water pressure and water content around a horizontal drift in the URL have been monitored for over 18 months since before the drift excavation was started. During the drift excavation, both pore water pressure and water content were decreasing. Pore water pressure has been still positive though it continued to decrease with its gradient gradually smaller after excavation, while water content turned to increase about 6 months after the completion of the excavation. It turned to fall again about 5 months later. An unsaturated zone containing gases which were dissolved in groundwater may have been formed around the horizontal drift.

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publisher：Japan Society of Material Cycles and Waste Management  

The achievement of reclamation conditions suitable for waste stabilization is expected when controlling the amount of water permeation through the cover layer at final landfill sites. The structure of a capillary barrier, which is one method to control the amount of water permeation, was examined from the viewpoint of water permeation control. Based on this examination, it was found that analytical predictions accurately corresponded to measurement results, thus, the prediction of water permeation was quite reliable. Therefore, it was determined that capillary barriers are effective in controlling water permeation.

DOI： 10.3985/jswme.19.318

CiNii Article

CiNii Books

researchmap

Other Link： https://jlc.jst.go.jp/DN/JALC/00321631778?from=CiNii

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

DOI： 10.2208/jscej.2003.743_199

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

In the south area in Cyugoku region, residual granite soil is distributed widely and it induced many slope failures at heavy rain. In this study, it showed the each process that reached model of slope failure, and for the establishing the system which could grasp a change of the slope stability that it monitored in the real slope. This method is technique to assume the arrival time of wetting front to base impermeable layer or water table with monitoring of water content changing. Furthermore, it performed numerical seepage analysis and examined consistency with monitoring data. It is understood that effective of the water content measurement as long-term method, but, for completion of a prediction system, some problem remained in measurement results and analysis precisions.

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10445158

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASCE-AMER SOC CIVIL ENGINEERS  

The development of a physically based warning system for rainfall-induced slope failures requires a comprehensive understanding of the failure process. A set of laboratory-scale soil slopes was subjected to instability, through three different modes of raising water level, to clarify the process of failure initiation. Hydrologic responses of the model slopes to the saturation process were recorded by volumetric soil moisture content sensors. The results of model tests show that failures of the model slopes were essentially initiated by the development of an unstable area near the slope toe, upon the formation of the seepage area, with shallow noncircular sliding being the dominant failure mode. The volumetric moisture content of the slope region where localized failures initiated was noted to reach a nearly saturated value. However, the major portion of soil slopes involved in overall instability was still in an unsaturated condition. Based oil the observed moisture content response of the model slopes, a concept for prediction methodology of rainfall-induced slope failures is introduced.

DOI： 10.1061/(ASCE)1090-0241(2007)133:5(575)

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The purpose of this study is proposing for the test method for measuring the hydraulic conductivity of bentonite mixtured soil used as a seal liner of waste disposal site after the construction in situ. Concretely, it is a method for building in the moisture sensor in which the measurement in the pinpoint was possible for Air Entry Permeameter, which exists in situ permeability test method. In results of this study, by catching fall time of wetting front, 10^-8(m/s) order of hydraulic conductivity could be measured in about 10 minutes. And, the validity of this proposed method was verified by carrying out the one-dimensional infiltrating test, and measuring moisture profile and pressure distribution in the test-piece.

DOI： 10.2208/jscejc.63.299

CiNii Article

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

The purpose of this paper is to improve technologies of the grouting for excavation disturbed zone in order to recover low permeable rock masses for research and development on geological disposal of high-level radioactive waste. In this study, experiments of grouting injection test are performed on bentonite slurry mixes with saline and ethanol in the laboratory. From the results of the tests, low viscous and high density bentonite slurry is found to be able to inject the concentrated bentonite slurry and to recover low permeable in the fine fractured aperture. In conclusion this bentonite slurry is able to be expected the grouting effects for excavation disturbed zone in order to recover low permeable rock masses.

DOI： 10.2208/jscej.2005.806_55

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

To estimate the degree of consolidation settlement, the soil mass conservation principle was used in this analysis. The specific storage coefficient was treated as a function of effective stress and void ratio. With this method, the behavior of consolidation from over-consolidation state to normal-consolidation state is easy to analyze. To evaluate its validity, results from the new method were compared with those from laboratory tests and Terzaghi's one-dimensional analysis. From these comparisons, it was shown that the principle is very accurate and reliable for estimating ground settlement. The new method was also used to analyse field conditions and to estimate settlement arising from (a) dewatering (pumping), (b) double-step load landfill phenomenon and (c) the disruption of groundwater flow during underground construction.

DOI： 10.2208/jscej.2005.799_1

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

For a long time, the permeability of soil is estimated from particle size distribution using D_<10> and D_<20> values. Still, there are some problems associated with this method. In this paper, a new method for estimating the permeability of soil is proposed. This is based on particle size distribution and compaction rate data that were obtained from laboratory tests. Under practical field conditions, the estimation of either porosity or void ratio is difficult. Therefore, from the N values, the compaction rate is estimated. Though the permeability values obtained from the new method are smaller than those obtained from other methods, the new method is fairly reliable.

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10444150

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

In order to predict the range of groundwater level fluctuation and the flow rate of spring water in a tunnel, which are caused by digging a mountain tunnel, some simple methods were proposed.<br>In this paper, the preconditions of these conventional simple methods are clarified. And new simple method, which can treat rainfall intensity and a coefficient of permeability that are not handled in these methods, is proposed by analyzing the results of a vertical-section-2-dimensional-finite-element-method. Moreover, based on results of new methods, the new method to set a range, which should be investigated and modeled for numerical analysis before excavation, is proposed.

DOI： 10.2208/jscej.2004.778_125

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The purpose of this paper is to propose the grouting material and method for fractured rock masses. So experimental study is executed in order to grasp that the properties of grouting material is stable and impermeable. In this study, experiments of hydraulic test and grouting injection test are performed on bentonite slurry mixes in the laboratory. From the results of the tests, a mixer of ethanol and bentonite is found to be very suitable for a grouting material. Also, dynamic grouting method is able to inject the concentrated bentonite slurry in the fractured aperture.

DOI： 10.2208/jscej.2004.764_221

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.5917/jagh1987.46.145

CiNii Article

CiNii Books

researchmap

Language：Japanese  

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS39.0.1235.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS39.0.1187.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS39.0.1211.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS39.0.1159.0

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：岡山大学環境管理センタ-  

CiNii Article

CiNii Books

researchmap

researchmap

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS38.0.1171.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS38.0.1173.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS38.0.1175.0

CiNii Article

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：環境技術学会  

DOI： 10.5956/jriet.31.766

CiNii Article

CiNii Books

researchmap

Other Link： https://jlc.jst.go.jp/DN/JALC/00159787241?from=CiNii

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Civil Engineers  

The purpose of this study is to improve the grouting method for fractured rock masses. So experimental study is executed in order to understand the properties of grouting injection and seepage flow in hydraulic fractured aperture. This paper grasps the effect of the properties of grouting stage due to the various conditions such as width of the aperture, viscosity of the grout, water cement ratio and injection flow rate using flat plate fractured model in a laboratory experiment. From the results, it is proposed to select the relationship between the most suitable grout mix (water cement ratio) and width of the aperture to be injected according to the properties of grouting stage.

DOI： 10.2208/jscej.2002.715_311

CiNii Article

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS37.0.2421.0

CiNii Article

researchmap

Publisher：The Japanese Geotechnical Society  

DOI： 10.11512/jiban.JGS37.0.2423.0

CiNii Article

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

CiNii Article

CiNii Books

researchmap

Other Link： http://ousar.lib.okayama-u.ac.jp/11531

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10441015

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：A A BALKEMA PUBLISHERS  

This paper presents the results of a series of laboratory slope failure experiments conducted to examine the effectiveness of monitoring moisture content to predict the occurrence of rainfall-induced slope failure. Numerical seepage analyses were also conducted prior to the experiments to identify the hydraulic response of the model slopes to the simulated rainfall. The changes in moisture content and pore-water pressure were monitored during rainfall infiltration and at the initiation of failures. The experiments showed that moisture content of soil slope increased to the saturated value at the time of failure. This indicated the possibility in predicting the critical time of failure initiation by monitoring the change in moisture content. Upon advantages of moisture sensing instruments over pore-pressure measuring instrument, therefore, monitoring of moisture contents during rainfall is more effective and more reliable than that of pore pressures to predict failure occurrences. The results of precise monitoring of moisture contents in the field to predict the rainfall-induced slope failures are encouraging.

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：土木春秋社  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

For some time, we have been working toward the "Realization of a Safe and Secure Society using ICT in Shiojiri-City, Nagano Prefecture." This is a project comprised of two phases: information gathering, and dissemination of information. For information gathering, we are developing systems to confirm the whereabouts of children and the elderly, who are vulnerable in disasters, and systems to gather information on the situation in mountainous regions, rivers etc. For dissemination of information, we are developing systems using broadcast technology for disseminating information to residents, such as disaster information and evacuation warnings derived from the gathered information. This presentation will describe the project goals, the background of the project thus far, and an overview of the developed system. The current situation and plans for the future will also be discussed.

CiNii Article

CiNii Books

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：English  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10445525

DOI： 10.2208/jscejc.64.340

researchmap

Language：Japanese   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10445306

Language：Japanese   Publisher：廃棄物学会  

CiNii Article

CiNii Books

researchmap

Language：Japanese   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10443407

Language：English  

CiNii Article

CiNii Books

researchmap

Language：Japanese  

CiNii Article

CiNii Books

researchmap

Language：English  

CiNii Article

CiNii Books

researchmap

Other Link： http://ousar.lib.okayama-u.ac.jp/11500

Language：Japanese   Publisher：地盤工学会  

CiNii Article

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10442689

Language：English  

CiNii Article

CiNii Books

researchmap

Event date： 2008.6.12

Language：Japanese  

researchmap

Event date： 2005.10.31

Language：Japanese  

researchmap

Presentation type：Oral presentation (general)  

researchmap

Presentation type：Oral presentation (general)  

researchmap

Presentation type：Oral presentation (general)  

researchmap

Presentation type：Oral presentation (general)  

researchmap

researchmap

Presentation type：Oral presentation (general)  

researchmap

Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap