Model identification and parameter estimation of elastoplastic constitutive model by data assimilation using the particle filter          下载免费PDF全文

Akira Murakami  Hayato Shinmura  Shintaro Ohno  Kazunori Fujisawa 《国际地质力学数值与分析法杂志》2018,42(1):110-131

Data assimilation, using the particle filter and incorporating the soil‐water coupled finite element method, is applied to identify the yield function of the elastoplastic constitutive model and corresponding parameters based on the sequential measurements of hypothetical soil tests and an actual construction sequence. In the proposed framework of the inverse analysis, the unknowns are both the particular parameter within the exponential contractancy model, n_E, which parameterizes various shapes for the yield function of the competing constitutive models, including the original/the modified Cam‐Clay models and in‐between models and the parameters of the corresponding constitutive model. An appropriate set, consisting of the yield function of the constitutive model and the parameters of the constitutive model, can be simultaneously identified by the particle filter to describe the most suitable soil behavior. To examine the validity of the proposed procedure, hypothetical and actual measurements for the displacements of a soil specimen were obtained for consolidated and undrained tests through a synthetic FEM computation and for consolidated and drained tests, respectively. After examining the applicability of the proposed procedure to these test results, the present paper then focuses on the actual measured data, ie, the settlement behavior including the lateral deformation of the Kobe Airport Island constructed on reclaimed land.  相似文献   

Mitigation of earthquake-induced damage of breakwater by geogrid-reinforced foundation     

Babloo Chaudhary  Hemanta Hazarika  Akira Murakami  Kazunori Fujisawa 《Marine Georesources & Geotechnology》2018,36(7):827-840

A strong earthquake often precedes a tsunami, and a breakwater may settle during the earthquake. Such seismic subsidence of the breakwater may reduce its ability to block the tsunami, and the tsunami may easily enter coastal areas by overflowing it. This study deals with the instability of a breakwater due to an earthquake. In addition, to protect a breakwater from damage caused by an earthquake, a new concept of using geogrid for reinforcing the foundation of a breakwater is introduced. To determine the behavior of unreinforced foundation and to evaluate the effectiveness of the proposed reinforced foundation under different earthquake loadings, a series of shaking table tests were performed. It was observed that the earthquake generated excess pore water pressures and deformations of foundation ground were main reasons of failure of the breakwater. The reinforced foundation was found effective to reduce the earthquake-induced damage of the breakwater, and finally it makes the breakwater resilient against earthquake-induced forces. Numerical simulations were also performed to elucidate the mechanism of reinforcement–breakwater–soil–water system under different earthquake loadings.  相似文献   

Development of partial factor design method on bearing capacity of pile foundations for Japanese Specifications for Highway Bridges     

Toshiaki Nanazawa  Tetsuya Kouno  Gaku Sakashita  Kazunori Oshiro 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(3):166-175

ABSTRACT

This paper shows the development of a partial factor design method on the bearing capacity of pile foundations for Japanese Specifications for Highway Bridges. Firstly, estimation design equations on the bearing capacities of pile foundations are improved by analysis of pile load test results and uncertainties in the bearing capacities are evaluated. Secondly, the reliabilities of pile foundations designed by the former specifications are evaluated based on reliability analysis considering the uncertainties in the bearing capacities and coefficients of subgrade reaction. Finally, a partial factor design method is developed based on the target reliability index obtained based on the conventional pile installation method by the pile installation methods. The factors are different for each pile installation method.  相似文献   

Detailed abundances of rare earth elements,thorium and uranium in chondritic meteorites: An ICP-MS study     

Kazunori Shinotsuka  Hiroshi Hidaka  Mitsuru Ebihara 《Meteoritics & planetary science》1995,30(6):694-699

Abstract— Inductively coupled plasma mass spectrometry (ICP-MS) was successfully applied to bulk samples of Allende, Jilin, Modoc, Saint-Séverin and Atlanta for the determination of rare earth elements (REE) (Y and 14 lanthanoids), Th and U. The results of ICP-MS showed good agreement with recommended values, and their reproducibilities were high enough to discuss the detailed abundances of lanthanoids and actinoids in chondritic meteorites. For the Allende reference sample issued by the Smithsonian Institution, a positive anomaly of Tm, a fractionation between light REE and heavy REE and a high Th/U ratio were observed in the CI-normalized abundances of REE, Th and U. These features are common for group II inclusions in Allende, suggesting that the abundances of refractory lithophiles in Allende are somewhat influenced by those in a specific constituent. For the other chondritic meteorites, a zigzag alteration was commonly observed in the heavy-REE region of their CI-normalized abundance patterns. It is suggested that such a zigzag pattern is attributable to erratically high abundances of monoisotopic REE (Tb, Ho and Tm) in the CI values. Abundances of REE, Th and U in the bulk samples are also discussed separately in detail.  相似文献   

Petrology of ultramafic xenoliths from Kishyuku Lava,Fukue-jima,Southwest Japan     

S. Umino  Eriko Yoshizawa 《Contributions to Mineralogy and Petrology》1996,124(2):154-166

 Ultramafic xenoliths are found in Kishyuku Lava, Fukue-jima, Southwest Japan. These include spinel lherzolite, harzburgite and dunite, as well as pyroxenite. The compositions of the constituent minerals of the peridotite xenoliths are in the range of upper mantle peridotites. Variable Cr/(Cr+Al) ratios (0.1–0.5) of spinel, together with a limited range in olivine composition (Fo₉₀–Fo₉₂), indicate that the xenoliths are derived from slightly to highly depleted residual mantle. The combination of previously published clinopyroxene-olivine geothermobarometry and clinopyroxene-orthopyroxene geothermometry applied to the xenoliths yields a high geotherm of 1070° C at 1.0 GPa up to 1200° C at 2.2 GPa. Existence of such depleted upper mantle is compatible with the existing model of asthenospheric injection during the rifting of the Northeast China and the Japan Sea. The high geotherm is caused by thermal perturbation due to the injection of the hot asthenosphere and/or post-rifting uprise of mantle diapirs since 11 Ma. Received: 15 May 1995 / Accepted: 3 January 1996  相似文献   

Thermal evolution of the Lesser Himalaya, central Nepal: Insights from K-white micas compositional variation     

Lalu Prasad Paudel  Kazunori Arita 《Gondwana Research》2006,9(4):409-425

The Lesser Himalayan low- to medium-grade metamorphic rocks in central Nepal are rich in K-white micas occurring as porphyroclasts and in matrix defining S₁ and S₂. Porphyroclasts are usually zoned with celadonite-poor cores and celadonite-rich rims. The cores are the relics of igneous or high grade metamorphic muscovites, and the rims were re-equilibrated or overgrown under lower T metamorphic conditions. The matrix K-white micas defining S₁, pre-dating the Main Central Thrust activity, are generally celadonite-rich. They show heterogeneous compositional zoning with celadonite-rich cores and celadonite-poor rims. They were recrystallized at lower T condition prior to the Main Central Thrust activity, most probably prior to the India–Asia collision (pre-Himalayan metamorphism). The matrix K-white micas along S₂, synchronous to the Main Central Thrust activity (Neohimalayan metamorphism), are relatively celadonite-poor and were recrystallized under relatively higher T condition. K-white micas defining S₁ also were partially re-equilibrated during the Neohimalayan metamorphism. The average compositions of recrystallized K-white micas defining both S₁ and S₂ become gradually poor in (Fe + Mg)- and Si-contents and rich in Al- and Ti-contents from south to north showing an increase of metamorphic grade from structurally lower to higher parts in the Lesser Himalaya. This shows that the metamorphism is inverted throughout the inner Lesser Himalaya. The tectono-metamorphic significance of the published K–Ar and ⁴⁰Ar / ³⁹Ar K-white micas ages from the Lesser Himalaya need re-evaluation in the context of observed intrasample compositional variation and zoning, and possible higher closure temperature (500 °C) for K–Ar system.  相似文献   

Study on submarine cable tension during laying     

Yoshizawa  N. Yabuta  T. 《Oceanic Engineering, IEEE Journal of》1983,8(4):293-299

In order to design submarine optical-fiber cable, it is very important to clarify the cable tension and fiber elongation during laying because the fiber elongation allowance is very small. When submarine cable is being laid from a cable ship, cable weight in water plus such additional tension as bottom tension caused by the negative slack and tension due to ship motion work upon the cable [1]. Cable tension changes during laying were theoretically studied. This paper quantitatively clarifies bottom tension dependence at the touchdown point caused by the negative slack upon both water depth and ship velocity. It is shown that the shallower the water depth is and the faster the ship velocity is, the larger the bottom tension is. The theoretical bottom tension showed good agreement with the experimental value measured during sea trials on laying submarine optical-fiber cable [2], [3]. This paper also describes the correlation between cable, ship motion, and cable tension vibration by examining experimental results. It quantitatively clarifies the tension vibration magnitude.  相似文献   

Correction to: A web-based real-time and full-resolution data visualization for Himawari-8 satellite sensed images     

Ken T. Murata  Praphan Pavarangkoon  Atsushi Higuchi  Koichi Toyoshima  Kazunori Yamamoto  Kazuya Muranaga  Yoshiaki Nagaya  Yasushi Izumikawa  Eizen Kimura  Takamichi Mizuhara 《Earth Science Informatics》2018,11(2):239-240

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Influence of IMF-sector polarity on the North-South asymmetry of geomagnetic activity and its relationship with solar wind parameters     

Yoshizawa Katsuaki 《Planetary and Space Science》1984,32(5):605-610

Relationships between the North-South asymmetry of the geomagnetic activity associated with the sector polarity of the interplanetary magnetic field (IMF) and various solar wind parameters are examined using the subauroral zone magnetic activity indices an and as. It is found that: (1) the effect of the sector polarity of IMF on the North-South asymmetry is due to the By-component of IMF, not to the Bx-component; (2) the asymmetry appears only when IMF is directed southward, being augmented by the increment of the magnitudes of the southward component and the solar wind velocity.  相似文献   

Occurrence characteristics of chaetognath species along the PM transect in the Japan sea during 1972–2002     

Naoki Nagai  Kazuaki Tadokoro  Kazunori Kuroda  Takashige Sugimoto 《Journal of Oceanography》2006,62(5):597-606

A long-term variation in dominant species of chaetognaths in the Tsushima Warm Current was analyzed using samples collected four times a year from 1972 to 2002 by the Maizuru Marine Observatory along the PM transect in the Japan Sea. Of 19 occurring species, 13 subtropical species formed a major portion of the standing stock. Species richness in the study area was similar to that in the East China Sea and the South China Sea. Four species, Sagitta minima, S. nagae, S. enflata, S. elegans dominated in the upper 150 m water column. The most dominant species per season were S. minima in both winter and autumn, S. elegans in spring and S. nagae in summer. Water temperature and salinity ranges of the most frequent occurrence for three dominant species revealed a common tendency in the order of S. nagae > S. minima > S. enflata towards colder temperature and higher salinity. Inter-annual abundance of chaetognath species fluctuated proportionally in response to the warm or cool phases in water temperature. Water temperature was a fundamental factor in regulating distributional occurrence, being more decisive than salinity. Changes of both dominant species and species numbers in relation to the reduced abundance during winter to spring and the subsequent increase during summer to autumn might be caused by specific differences in optimum temperature. Chaetognath species are important as an indicator of water masses and significant for our understanding of changes and evaluations of the Japan Sea ecosystem.  相似文献