Kyohei Ueda

The Liquefaction Experiments and Analysis Project (LEAP) is a joint international project that pursues the verification, validation and uncertainty quantification of numerical liquefaction models. As part of this project, twenty-three Hollow Cylinder Cyclic Torsional Shear Tests were conducted in the installations of the Disaster Prevention Research Institute at Kyoto University, focusing on the influence of the relative density and the K0 effects in the cyclic response of Ottawa F-65 Sand. The

The seismic behavior of a suction bucket foundation for offshore wind turbine systems is studied using centrifuge model tests with a scaling factor of 1/100 and an effective stress analysis based on the strain space multiple mechanism model implemented in the FLIP computer code (Finite element analysis program of Liquefaction Process). The primary dimensional parameters of the prototype scale suction bucket foundations selected for this study are as follows: skirt length L = 8 m, diameter D = 19

The generalized scaling law is based on the concept of two-stage scaling and allows currently available centrifuge facilities to model a large-scale prototype expanding over the spatial dimension ranging from 30 m or larger subject to earthquake motions. This paper presents the results of investigation on the applicability of the generalized scaling law to the fully nonlinear regime of soil-structure system with the induced strain level of 10% in the order of magnitude. The centrifuge model test

Summary Consideration of fabric anisotropy is crucial to gaining an improved understanding of the behavior of granular materials. This paper presents a constitutive model to describe the sand behavior associated with fabric anisotropy within a framework of a strain space multiple mechanism model. In the proposed model, a second‐order fabric tensor is extended by incorporating a new function that represents the effect of inherent (or initial fabric) anisotropy, along with three additional paramet

Inherent anisotropy is a crucial aspect to consider for an improved understanding of the strength and deformation characteristics of granular materials. It has been the focus of intense investigation since the mid-1960s. However, inherent anisotropy’s influence on ground seismic responses, such as liquefaction, has not been extensively studied. In this paper, inherent anisotropy’s influence on ground seismic responses is examined through a series of dynamic centrifuge model tests on liquefiable

Abstract Inherent anisotropy is a crucial aspect to consider to improve one's understanding of the behavior of granular materials, in particular, noncoaxial responses under proportional and nonproportional loadings. This article investigates the capability of a strain space multiple mechanism model to reproduce complex responses of inherently anisotropic soils under various loading paths. The constitutive model has been expanded upon to account for the effect of inherent anisotropy by incorporat

Cyclic undrained triaxial tests are commonly used in research and practical design to evaluate the liquefaction resistance of sandy soils. This paper aims to propose a methodology to evaluate liquefaction resistance by considering the variability or uncertainty associated with experimentation, using Bayesian statistics with a Markov chain Monte Carlo technique. In addition to conventional nonhierarchical Bayesian modeling, hierarchical Bayesian modeling is adopted to properly incorporate the fac

2011年東北地方太平洋沖地震において甚大な液状化が生じた浦安市の地盤モデルを対象に，長継続時間地震動を受ける地盤の液状化に及ぼす透水性および余震の影響を調べるため，間隙水の移流を考慮した有効応力解析を実施した．解析の結果，1) 透水性の良いきれいな礫から成る地盤を除き，長継続時間地震動であっても少なくとも振動中は地盤の液状化に及ぼす透水性の影響は顕著でないこと，2) 余震のみ（45gal程度）が作用した場合には液状化が発生しないのに対し，本震後において0.5程度の過剰間隙水圧比が残っている状態で余震が作用した場合には，再液状化が発生する可能性が高まるとともに，最終的な沈下量の増大に及ぼす余震の影響が無視できないこと，などがわかった．