Faculty Profiles - NODA, Toshihiro

Papers - NODA, Toshihiro

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Localized/enormous seismic damage of subsurface ground induced by the stratum irregularity International journal

Nakai, K. and Noda, T.

Proc. of the 17th World Conference on Earthquake Engineering (17WCEE) page： 1d-0092 2020.9

Numerical analysis on aftershock-induced liquefaction of sandy ground with water-level raised by main shock International journal

Yoshikawa, T. and Noda, T.

Proc. of the 17th World Conference on Earthquake Engineering (17WCEE) page： 4b-0051 2020.9

Validation of the applicability of a drainage method for reducing settlement and inclination of utility poles in liquefied ground Reviewed

ITO, H., ISHIMARU, M., NAKAI, K. and NODA, T.

Vol. 15 ( 3 ) page： 643 - 652 2020.9

Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)

In the 2011 Earthquake off the Pacific coast of Tohoku, extensive liquefaction occurred in the Kanto region. This resulted in the settlement and inclination of thousands of utility poles. In urban areas, utility poles are often installed in narrow easements with limited clearance. Therefore, a simple and inexpensive countermeasure is desired. In this study, we attempted to reduce the settlement and inclination of utility poles in the liquefied ground by providing drain
holes in the utility pole. In the centrifugal model tests conducted using pole models with drain holes at the bottom and sides, settlement and inclination decreased in relation to the amount of drainage. Therefore, it was determined that the drainage method has a definite effect on the reduction of both settlement and inclination of utility poles in the
liquefied ground.

DOI： https://doi.org/10.3208/jgs.15.643

Scopus

Deformation-failure mechanism of saturated fill slopes due to resonance phenomena based on lg shaking-table tests (vol 55, pg 1668, 2018)

Murao Hidehiko, Nakai Kentaro, Noda Toshihiro, Yoshikawa Takahiro

CANADIAN GEOTECHNICAL JOURNAL Vol. 57 ( 8 ) page： 1263 - 1263 2020.8

Soil-water-air coupled finite deformation simulation of model test on seepage failure of levee Reviewed

Vol. 75 ( 2 ) page： I_379 - I_388 2020.2

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

Due to heavy rain in northern Kyushu in July 2012, failure of the Yabe River levee occurred, caused by local piping in highly permeable foundation ground, and it was a great shock when river engineers and researchers realized that levees can collapse without overflow. Regarding the Koyoshi River levee slope slip and the Kakehashi River levee slope failure that occurred in July 2013, it is also considered that the damage was the result of highly permeable foundation ground. In this paper, to clarify the seepage failure mechanism of river levee with highly permeable foundation ground, numerical simulations of model tests were conducted using a soil-water-air coupled finite deformation analysis code. As a result, the simulation was able to reproduce the difference between the case when the seepage failure occurred and the case when the seepage failure did not occur in the experiment. In addition, using this analysis code, case studies were conducted and the influence of introducing suction effect to elastoplastic constitutive model on seepage failure behavior was also discussed.

DOI： 10.2208/jscejam.75.2_I_379

Reduction effects of liquefaction damage using small scale floating grid-type improvement for existing small scale structure Reviewed

Vol. 75 ( 2 ) page： I_329 - I_339 2020.2

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

Earthquake resistance of important structure have been promoted based on the lessons learned from the big Earthquake in Japan. However, liquefaction still causes serious damages to many detached houses in the world. Also, most soil improvement methods apply to original ground without structure, and countermeasure against liquefaction for existing small structure has not been sufficiently investigated. Therefore, we investigated reduction effects of liquefaction damage using small grid-type improvement as countermeasure against liquefaction for existing small structure. To this end, 2D model tests under 1g condition and non-linear FEM analyses have been carried out. From the model tests results, it was found that if the interval of improved wall is within 1.2 times of the base width, some degree of counter measure effect agaisnrt subsidence due to liquefaction can be obtained with a small grid-type improvement where the improvement depth is about twice the base width. The numerical simulation has shown a similar result as found in the observations.

DOI： 10.2208/jscejam.75.2_I_329

Influence of neighboring houses on liquefaction damage of detached houses Reviewed

Vol. 75 ( 2 ) page： I_401 - I_410 2020.2

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

In the 2011 off the Pacific Coast of Tohoku Earthquake, the liquefaction damage in the residential area of Urayasu City was huge, and many detached houses suffered uneven settlement. In Japan, however, there has not been sufficient knowledge about liquefaction- induced damage of detached houses. Therefore, in this study, with regard to the liquefaction damage form of the detached houses constructed on the liquefiable ground, the following points were clarified focusing on the influence of the neighboring houses using soilwater coupled finite deformation analysis. 1) In the case of single structure evaluation, even if stability is maintained without tilting, tilting damage may occur when considering neighboring houses. 2) The direction of inclination of neighboring houses can be explained by using the computed direction of post-seismic displacement vector in the case of one house alone.

DOI： 10.2208/jscejam.75.2_I_401

Undrained cyclic shear behavior of clay under drastically changed loading rate International journal

Khan Imran, Nakai Kentaro, Noda Toshihiro

INTERNATIONAL JOURNAL OF GEOMATE Vol. 18 ( 66 ) page： 16 - 23 2020.2

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

The earthquake damage prediction is mainly focused on the seismic instability of sandy foundations although the clayey foundation could also be vulnerable to earthquake damage. Moreover, it is known that clayey soil shows a marked loading rate dependency in monotonic shear behavior due to its low permeability. Therefore, this paper aims to determine the undrained cyclic shear behavior of clayey soil under a drastically changed loading rate. Reconstituted clayey samples were subjected to undrained cyclic triaxial compression/extension tests with loading rate from 1.0Hz to 0.0042Hz by stress control, and 0.01%/min by strain control. The cyclic loading was stopped when the double amplitude exceeded 5%. Then, the specimen was left for a while in an undrained condition, until the value of pore water pressure converged. Results revealed that as the loading rate decreases, the number of cycles that corresponds to DA=2% and 5% also decreased. Therefore, the degree of strain evolution varies depending on the loading rate and the undrained shear strength also varies depending on the cyclic loading rate. This is because when the cyclic loading rate was high; the pore water did not migrate sufficiently, leading to the non-uniform distribution of the excess pore water pressure inside the specimen. However, the final values of excess pore water pressure after the homogenization process was the same regardless of the loading rate. This means that if sufficient time is left after cyclic loading, the final mean effective stress value becomes equal regardless of the loading rate.

DOI： 10.21660/2020.66.07893

Web of Science

Scopus

Experimental research on development/diminishing of anisotropy and its effect on mechanical behavior of clay Reviewed International journal

Khan Imran, Nakai Kentaro, Noda Toshihiro

INTERNATIONAL JOURNAL OF GEOMATE Vol. 18 ( 65 ) page： 9 - 14 2020.1

An analytical consideration on aftershock-induced expansion of liquefaction damage of sandy ground with groundwater-level rise due to main shock International journal

Proc. of 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019 2020

Correction: Deformation–failure mechanism of saturated fill slopes due to resonance phenomena based on 1g shaking-table tests (Can. Geotech. J., 55(11), 1668-1681, 2018, 10.1139/cgj-2017-0385) International journal

Murao H., Nakai K., Noda T., Yoshikawa T.

Canadian Geotechnical Journal Vol. 57 ( 8 ) 2020

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Canadian Geotechnical Journal

Replace Fig. 10 with the figure shown herein, where labels “(a)” and “(b)” have been added; and “ch.3 (upper)”, “ch.2 (middle)”, and “ch.1 (lower)” in part (b) of the figure have been replaced with “ch.6 (upper)”, “ch.5 (middle)”, and “ch.4 (lower)”, respectively.(Image presented).

Scopus

Numerical simulation of Riedel shear bands formation considering effects of geometrical barrier on strike-slip fault International journal

Toyoda T., Noda T., Yamada S., Asaoka A.

16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019 2020

Language：English Publishing type：Research paper (scientific journal) Publisher：16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019

Displacements of strike-slip faults generate Riedel shear bands and flower structures at the surface ground above the faults. This paper aims to simulate deformation of strike-slip deformation of the surface ground considering jogs as geometrical imperfections. Analyses are based on the GEOASIA with SYS Cam-clay model that considers overconsolidation, which allows us to simulate softening behavior of brittle materials. Since the analytical results consider the presence of jogs, fractal shear zones (duplexes), P-shear, R/R'-shear, outer shear/splay shear, and tulip/palm-tree structures are successfully simulated. Furthermore, in terms of the scale effect, Riedel shear bands fractally appear when setting same overconsolidation ratio at the bottom of models.

Scopus

Numerical simulation of Riedel shear bands formation considering effects of geometrical barrier on strike-slip fault International journal

Toyoda Tomohiro, Noda Toshihiro

Proc. of the 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering (16ARC) page： JGS-064 2019.10

Language：English

Soil-water-air coupled elasto-plastic finite deformation simulation of unsaturated silt triaxial test using void ratio-dependent soil water retention model International journal

Yoshikawa Takahiro, Noda Toshihiro

Proc. of the 7th Asia-Pacific Conference on Unsaturated Soils (AP-UNSAT2019) page： EA56 2019.8

Language：English

A soil-water-air coupled finite deformation analysis of unsaturated silt triaxial tests, which were conducted by Kodaka et al. (2006), was performed considering the triaxial test not as an element test but as an initial and boundary value problem. The analysis can deal with suction effect accounting it in the elasto-plastic constitutive equation, SYS Cam-clay model. A series of processes of suction variation, isotropic consolidation, and exhausted-drained shearing were simulated beginning from a single initial condition and using a single set of material constants. The results showed that considering ceramic disc permeability was required to reproduce well both the mechanical and hydraulic behavior. Accordingly, it is suggested that a laboratory test result should be seized as the solution for an initial and boundary value problem. In addition, to experimentally clarify that the ceramic disc permeability is comparatively low, unsaturated silt triaxial tests were conducted using both a ceramic disc and a micro-porous membrane for suction control.

An analytical study on expansion of liquefaction damage during aftershock induced by groundwater-level rise due to main shock International journal

Noda Toshihiro, Yoshikawa Takahiro

Proc. of the 7th Asia-Pacific Conference on Unsaturated Soils (AP-UNSAT2019) page： EA59 2019.8

Authorship：Lead author Language：English

Extensive liquefaction damage was observed in the 2011 off the Pacific coast of Tohoku Earthquake over a wide range of reclaimed coastal land. It is reported that in Chiba Prefecture, the large aftershock that occurred 29 minutes after the main shock extended the liquefaction damage in sandy ground. In this paper, using a soil-water-air coupled finite deformation analysis code incorporating the elasto-plastic constitutive equation SYS Cam-clay model, it is shown that the groundwater level rises due to the main shock and that during the aftershock, this groundwater level rise could cause extended liquefaction damage.

Development and verification of a soil-water coupled finite deformation analysis based on u-w-p formulation with fluid convective nonlinearity Reviewed International journal

Noda Toshihiro, Toyoda Tomohiro

SOILS AND FOUNDATIONS Vol. 59 ( 4 ) page： 888 - 904 2019.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Soils and Foundations

Most soil–water coupled analyses of saturated soil are based on the u–p formulation, where a set of equations is reduced by assuming that the acceleration of the fluid phase relative to that of the solid phase is less than that of the solid phase. Therefore, this analysis cannot be used for a coupled analysis with dynamic water flow in highly permeable soil. This study aims to present a soil–water coupled finite deformation analysis method based on full formulation, or u–w–p formulation. This method differs from conventional methods in the following ways: (1) the governing equations explicitly include the equation of motion for the fluid phase, (2) a relative convective term is used to describe a change in the relative configuration between the two phases, and (3) the moving/inclined discharge boundary is directly implemented to the discretized governing equations. Herein, one/two dimensional seepage and plane-strain deformation analysis results are reported. In the seepage analysis, accelerating permeation of pore water is obtained and the undrained constraint condition is verified. In the deformation analysis, dynamic migration in a high permeable soil specimen, i.e., wave propagation and rotational flow of pore water, is observed.

DOI： 10.1016/j.sandf.2019.03.008

Web of Science

Scopus

Validation for the effectiveness of vacuum consolidation method including the one with air-water separation system using a numerical simulation approach Reviewed

Vol. 75 ( 5 ) page： 303 - 315 2019.7

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

In the vacuum consolidation method, the pressure under the air-tight sheet increases according to ground surface settlement. An air-water separation system for the vacuum consolidation method (VCM) was developed to improve this issue and enhance the vacuum effect. Although it has been demonstrated up to today that the system can obtain a higher vacuum pressure, the suppression effect of the new type VCM against deformation has never been discussed. In this study, therefore, mainly to reveal the suppression effect of the new method against deformation, several numerical simulations were conducted by using a soil-water coupled analysis code, GEOASIA, which mounts the macro-element method with discharge and drainage functions of vertical drains. The main findings of this study are as follows: 1) The air-water separation system has a high efficiency against deformation. Especially, the method remarkably restricts settlement that occurs after stopping vacuum pumps because it has a high preloading effect. 2) The conventional VCM also restricts deformations including a lateral deformation even if large settlement occurs. This is because the vacuum loading effect is maintained even though the pressure under the airtight sheet increases according to ground surface settlement. 3) Short-term constructions that have never been attempted can be performed in both the type VCMs. The above discussions demonstrated that the
numerical simulation method used in this study allows the selection of effective countermeasures and
economical construction conditions.

DOI： https://doi.org/10.2208/jscejge.75.303

Non-contact estimation of strain parameter-triggering liquefaction Reviewed International journal

Uy Erica Elice S., Noda Toshihiro, Nakai Kentaro, Dungca Jonathan R.

INTERNATIONAL JOURNAL OF GEOMATE Vol. 16 ( 57 ) page： 82 - 88 2019.5

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

The strain parameter-triggering liquefaction is usually determined by implementing cyclic strain approach with a corresponding laboratory experiment. These parameters are threshold shear strain, cyclic shear strain and cyclic shear strain that would trigger liquefaction. In this study, non-contact measurement technique was implemented to estimate and monitor the development of the mentioned parameters. In this technique, a mirrorless camera and Lucas and Kanade pyramidal optical flow algorithm were utilized to track the movement of the particles. The camera was first calibrated to eliminate the errors from the lens and the scene as well. Furthermore, curvature correction was applied because the sample tested has a curved profile. The comparison was made with the loose and medium dense conditions. The samples were tested under a consolidated undrained cyclic triaxial test at 2.4, 1.6 and 0.8 mm strain amplitudes. The confining pressures used were 50, 100 and 200 kPa. Based on the results, a non-contact measurement technique can estimate the parameters. A range of values was established due to the non-homogeneous movement of the soil.

DOI： 10.21660/2019.57.4722

Web of Science

Scopus

Development of Disaster Response Applications and Improvements in Regional Disaster Prevention Capacity Based on Collaborative Information Use International journal

Noda Toshihiro, Yamori Katsuya, Harada Kenji

JOURNAL OF DISASTER RESEARCH Vol. 14 ( 2 ) page： 375 - 386 2019.3

Soil-water-air coupled finite deformation simulation of model test on seepage failure of levee Reviewed

Vol. 75 ( 2 ) page： I_379 - I_388 2019.2

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

Due to heavy rain in northern Kyushu in July 2012, failure of the Yabe River levee occurred, caused by local piping in highly permeable foundation ground, and it was a great shock when river engineers and researchers realized that levees can collapse without overflow. Regarding the Koyoshi River levee slope slip and the Kakehashi River levee slope failure that occurred in July 2013, it is also considered that the damage was the result of highly permeable foundation ground. In this paper, to clarify the seepage failure mechanism of river levee with highly permeable foundation ground, numerical simulations of model tests
were conducted using a soil-water-air coupled finite deformation analysis code. As a result, the simulation
was able to reproduce the difference between the case when the seepage failure occurred and the case when the seepage failure did not occur in the experiment. In addition, using this analysis code, case studies were conducted and the influence of introducing suction effect to elastoplastic constitutive model on seepage failure behavior was also discussed.

DOI： https://doi.org/10.2208/jscejam.75.2_I_379

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Papers - NODA, Toshihiro