Research Achievements - Original paper -
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Mechanism of sampling disturbance for peat ground and its influence on mechanical properties
Yamazoe N.
Soils and Foundations ( Soils and Foundations ) 63 ( 5 ) 101361 - 101361 2023.10 [Refereed]
Research paper (journal) Domestic Co-author
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VIBRATION CHARACTERISTICS OF SELF-MONITORING BENDER ELEMENTS WITH VARIOUS DIMENSIONS AND GEOMETRIES
Toshihiro OGINO, Shinya NISHIO
79 ( 15 ) 2023.01 [Refereed]
Research paper (journal) Single author
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Comparison of prediction performance for S-wave arrival point in bender element test using various machine learning models
MOMIYAMA Shoya, OGINO Toshihiro
Artificial Intelligence and Data Science ( Japan Society of Civil Engineers ) 4 ( 3 ) 60 - 69 2023 [Refereed]
Research paper (journal)
In Bender Element tests, determining the arrival time of the S-wave is often challenging from received waveforms. To improve the accuracy of S-wave arrival time prediction using machine learning as decision support for experimenters, we created three machine learning models based on support vector regression, Gaussian process regression, and neural network. We compared their prediction accuracies. We obtained 7240 artificial received waveforms with true S-wave arrival times from the linear system theory and trained the models using 11-dimensional features reflected from waveforms and test condition. The prediction performance of three models were compared using the errors between predicted arrival times and the values determined by an expert. The comparison revealed characteristics of each model in prediction and that Gaussian process regression model demonstrated the closest approximation to the values determined by the expert.
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Estimation of pore water pressure in aquifers using a time series model based on field observation in landslide site
AIHARA Wataru, OGINO Toshihiro, FUJII Noboru, KURIYAMA Daisuke, OGITA Shigeru
Artificial Intelligence and Data Science ( Japan Society of Civil Engineers ) 4 ( 3 ) 328 - 336 2023 [Refereed]
Research paper (journal)
In this study, a state-space model based on a tank model was constructed, and field observation data obtained from a landslide site in Kobuchi area, Akita Prefecture, from 2018 to May 2022, were fitted. The estimation was conducted for outflow volume from the landslide site and the water levels in five representative boreholes. The estimated results obtained through Markov chain Monte Carlo method fairly captured the behaviors of water levels and outflow volume. Furthermore, based on the estimated water levels of the tanks, the changes in pore water pressure acting on the aquifers of the landslide site were estimated.
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Evaluation of slope soundness using state space models based on expressway inspection data
MARUYAMA Kouki, OGINO Toshihiro, HOSHINO Katsuyuki, MIYAKOSHI Makoto
Artificial Intelligence and Data Science ( Japan Society of Civil Engineers ) 4 ( 3 ) 320 - 327 2023 [Refereed]
Research paper (journal)
In this study, based on number of damaged places and their damage degree data which are obtained from slope inspection of expressway, two time-series models were developed using state space model to estimate soundness index of slopes for each expressway route. The soundness index of slopes was defined as three latent states: occurrence rate of the damaged places, the number of occurred damaged place, and the occurrence probabilities of damage degrees. The developed models were fitted using inspection data from three expressway routes in Akita Prefecture. The estimation of soundness index was performed using the Markov chain Monte Carlo method. Based on the estimation results, a discussion on the temporal variations of these latent states is presented.
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PREDICTION OF S-WAVE ARRIVAL POINT ON RECEIVED SIGNAL OF BENDER ELEMENT TEST USING MACHINE LEARNING
MOMIYAMA Shoya, OGINO Toshihiro
Intelligence, Informatics and Infrastructure ( Japan Society of Civil Engineers ) 3 ( J2 ) 76 - 84 2022 [Refereed]
Research paper (journal) Single author
Generalization performance of a support vector regression model for the bender element test of which the S-wave arrival point is often difficult to determine on the received signal has been examined for the purpose of assisting experimenters' determination. Based on linear theory, 8960 received signals were numerically generated using realistic parameters. Then the model was trained with predictors of 11 dimensions which were extracted from the signal shape and the test condition as well as the true arrival point of the S-wave. The model has been validated by comparing the predicted values with the true arrival points using the synthetic signals. The prediction has also been made for a series of received signals in actual bender element tests which were conducted in Toyoura sand, a legorith simulant, and a peat and compared with arrival points which were determined by an expert. The prediction has substantially agreed with the expert's determination.
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MODELING OF NATURAL WATER CONTENT DISTRIBUTION OF A PEATY GROUND AND ESTIMATION OF CONFIDENCE INTERVAL USING STATISTICAL METHOD
ABE Takenari, OGINO Toshihiro, HAYASHI Hirochika, NISHIMURA Satoshi, TANAKA Hiroyuki, YAMAZOE Nobutaka, TAGUCHI Takeshi
Intelligence, Informatics and Infrastructure ( Japan Society of Civil Engineers ) 3 ( J2 ) 158 - 167 2022 [Refereed]
Research paper (journal) Single author
Based on 675 natural water content data obtained from a peaty ground in the Ishikari River basin, Hokkaido, the probabilistic distribution of the natural water content has been modeled as functions of the depth using generalized linear model. Combination of three kinds of probability density functions for the water content distribution and six polynomial expressions for the mean from zero to five orders in terms of the depth have been examined for searching the best model. By comparing the 18 models from statistical and engineering viewpoints, the best models for organic and inorganic soils have been proposed, respectively. The validity of the models has also been confirmed. To estimate the in-situ natural water content distribution, the confidence intervals for the mean, 5 percentile, and 95 percentile points of the water content distribution of the proposed models have been calculated by employing bootstrapping method.
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Correlation between motion of source bender element and feedback signal induced by self-monitoring
Ogino T.
Soils and Foundations ( Soils and Foundations ) 2021.01 [Refereed]
Research paper (journal) Single author
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Toshihiro OGINO
soils and foundations 2019.03 [Refereed]
Research paper (journal) Single author
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真空圧および盛土荷重による複合的な載荷を受ける泥炭の変形挙動－三軸試験によるシミュレーション－
荻野俊寛，山添誠隆，三田地利之，林 宏親，高橋貴之
地盤工学ジャーナル 12 ( 2 ) 263 - 275 2017.04
Research paper (journal) Domestic Co-author
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Identification method of travel time based on the time domain technique in bender element test for sandy and clayey soils
Takayuki Kawaguchi, Toshihiro Ogino, Satoshi Yamashita, Shunzo Kawajiri
Soils and Foundations 56 ( 5 ) 2016.11 [Refereed]
Research paper (journal) Domestic Co-author
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Strength and deformation characteristics of peat evaluated by triaxial tests simulating vacuum consolidation with fill loading
Toshihiro Ogino, Nobutaka Yamazoe, Takayuki Takahashi, Masaki Tsushima
Geotechnics for Sustainable Infrastructure Developmant - Geotec Hanoi 2016 - 683 - 690 2016.11 [Refereed]
Research paper (journal) Domestic Co-author
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Strength and Deformation Characteristics of Peat under Combined Loading of Vacuum Pressure and Axial Stress
Toshihiro Ogino, Takayuki Takahashi
733 - 734 2016.07
Research paper (journal) Domestic Co-author
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Velocity Profiles in the Shallow Lunar Subsurface Deduced from Laboratory Measurements with Simulants
Toshihiro Ogino, Taizo Kobayashi, Takayuki Takahashi, Hiroshi Kanamori
Journal of Aerospace Engineering, ASCE 29 ( 5 ) 2016.05 [Refereed]
Research paper (journal) Domestic Co-author
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Report on Debris Disaster Caused by the August 2013 Heavy Rain in Akita Prefecture
63 ( 11 ) 26 - 29 2015.11 [Refereed]
Research paper (journal) Single author
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YAMAZOE Nobutaka, TANAKA Hiroyuki, HAYASHI Hirochika, OGINO Toshihiro, MITACHI Toshiyuki
Japanese Geotechnical Journal ( The Japanese Geotechnical Society ) 8 ( 4 ) 517 - 532 2013 [Refereed]
Research paper (journal) Single author
This paper discusses horizontal coefficient of consolidation (ch) for prediction of consolidation settlement in peaty ground improved by plastic-board drain (PBD). A numerical analysis is carried out on two nearby sites of test embankments on peaty grounds improved with and without PBD. It is found that the coefficients of consolidation back-calculated from the analysis were significantly different between the grounds which were improved or not; ch for PBD improvement ground was 15 times as small as that without PBD. We deduce that water passageways locally grown in the peaty ground lead to high permeability and raise the effective coefficient of consolidation for unimproved ground. On the other hand, for improved ground, the effective coefficient of consolidation is less affected by the water passageways because of the short distance of horizontal drainage towards the PBD. As a result, The value of horizontal coefficient of consolidation ch approaches that obtained by laboratory consolidation test. In addition, our simulation shows that the effective horizontal coefficient of permeability in the peaty grounds was predicted smaller than the effective vertical one. We conclude that this result implies strong effect of disturbance induced by installing the PBD into the ground.
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SATO Nozomi, OGINO Toshihiro, TAKAHASHI Takayuki, HAYASHI Hirochika, OIKAWA Hiroshi
Japanese Geotechnical Journal ( The Japanese Geotechnical Society ) 8 ( 1 ) 133 - 142 2013 [Refereed]
Research paper (journal) Single author
Based on results of triaxial or torsion cyclic loading tests on a variety of soils containing organic matters such as highly organic soil or organic clay obtained from Hokkaido or Akita prefecture, empirical equations for elastic shear modulus <i>G</i><sub>0</sub> and reference strain γ<sub>r</sub> are proposed. Density of soil particles, which exhibits good correlation to ignition loss, is introduced as a parameter reflecting content of organic matter in the equation for <i>G</i><sub>0</sub>. In case of saturated soil, this equation is roughly consistent with other researchers’ equation proposed so far by parameters being replaced into water content. Based on a relationship between γ<sub>r</sub> and <i>G</i><sub>0</sub> derived by formula of Hardin-Drnevich model, the empirical equation for γ<sub>r</sub> is successfully expressed as a function of water content and consolidation stress. Compared with prediction from equations proposed, test results fall in a range of 0.7 to 1.5 times for <i>G</i><sub>0</sub> and of 0.5 to 2.0 times for γ<sub>r</sub>.
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Distinctive Soils in Tohoku Region
60 ( 10 ) 28 - 29 2012.10 [Refereed]
Research paper (journal) Single author
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Distinctive Soils in Tohoku Region(<Theme>Tohoku Branch Issue)
OginoToshihiro, KiyoharaYukou, SentoNoriaki
60 ( 10 ) 28 - 29 2012.10 [Refereed]
Research paper (journal) Single author
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MITACHI Toshiyuki, YAMAZOE Nobutaka, HAYASHI Hirochika, OGINO Toshihiro
Doboku Gakkai Ronbunshuu C ( Japan Society of Civil Engineers ) 66 ( 1 ) 1 - 20 2010 [Refereed]
Research paper (journal) Single author
Taking into account of application practice of deformation analysis on highly compressible peaty soft ground, FE analyses based on well-known several constitutive models were performed on two test embankments whose magnitude of loading are quite different with each other. Through the comparison with the field observation, the applicability of the constitutive models and the methods of deformation analysis were investigated. Comparisons of <i>K</i><sub>0</sub>-consolidated undrained triaxial compression and extension test results with analytical ones were also conducted to investigate the applicability of the models to the element test on undisturbed and reconstituted peat samples. This study has revealed that the models which characterize smaller shear strength and deformation resistance in the extension mode have a tendencyto overestimate the horizontal displacement of the ground around the embankment and the analysis based on the finite strain should be performed in case that the stress state reaches to the critical state due to large magnitude of loading.