Liquefaction Resistances of Unsaturated Non-Plastic Silt

Okamura, Mitsu; Noguchi, Kohei

doi:10.3208/sandf.49.221

Cited by 45 publications

(21 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Unno et al [1,5] conducted a series of strain-controlled cyclic triaxial tests on the unsaturated sand under fully undrained conditions, namely, unexhausted air and undrained water, to study the general liquefaction state of unsaturated soils. Okamura et al [6,7] observed the influence of air and suction pressures on the liquefaction resistance of unsaturated soils through a series of cyclic triaxial tests on a fine clean sand and non-plastic silt under fully undrained conditions. Tsukamoto et al [8] conducted a series of undrained stress-controlled cyclic triaxial tests on the unsaturated sand in order to examine the changes in the cyclic resistance of silty sand with different grain compositions.…”

Section: Introductionmentioning

confidence: 99%

“…The degree of saturation, which has a significant effect on the cyclic behavior of the unsaturated soil, has also been recognized. The cyclic shear strength of the unsaturated soil increases with the decreasing degree of saturation [1,[3][4][5][6][7][8]. Some results showed that the cyclic stress ratio almost doubled as the degree of saturation decreased from 100% to 90% [4,6].…”

Section: Introductionmentioning

confidence: 99%

“…According to the hypothesis that the individual soil particles and water are incompressible in comparison with the soil skeleton, a change in the volume of the soil skeleton is assumed to be equal to that of pore air under fully undrained cyclic loading [5]. The pore air absorbs the generated excess pore pressures resulted in a reduction in the pore-air volume [6,7]. A reduction in the volume of unsaturated soils during fully undrained cyclic loading causes an increase in the degree of saturation [1,5].…”

Section: Introductionmentioning

confidence: 99%

“…A reduction in the volume of unsaturated soils during fully undrained cyclic loading causes an increase in the degree of saturation [1,5]. Suction is a mechanism that affects the cyclic behavior of unsaturated soils [7]. It is usually indicated that suction increases the stiffness of the soil.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fully undrained cyclic loading simulation on unsaturated soils using an elastoplastic model for unsaturated soils

Komolvilas

Kikumoto

2016

E3S Web Conf.

View full text Add to dashboard Cite

Abstract. Several researchers have reported that Bishop's mean effective stress decreases in unsaturated soils under fully undrained cyclic loading conditions, and unsaturated soils are finally liquefied in a similar manner as saturated soils. This paper presents a series of simulations of such fully undrained cyclic loading on unsaturated soils using an elastoplastic model of the unsaturated soil. This model is formulated using the Bishop's effective stress tensor incorporating the following concepts: the volumetric movement of the state boundary surface containing the normal consolidation line and the critical state line due to the variation in the degree of saturation, a soil water characteristic curve model considering the effect of specific volume and hysteresis, the subloading surface model, and Boyle's law. Comparisons between the simulation results and the experimental ones show that the model agreed well with the unsaturated soil behavior under cyclic loading. Finally, the typical cyclic behavior of unsaturated soils under fully undrained conditions, such as the mechanism of liquefaction of unsaturated soils, the compression behavior, and an increase in the degree of saturation, are described through the proposed simulation results.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fully undrained cyclic loading simulation on unsaturated soils using an elastoplastic model for unsaturated soils

Komolvilas

Kikumoto

2016

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…In comparison to studies on fully drained (i.e., dry) or fully saturated sands, studies on the mechanical properties of partially saturated sand are relatively new and can be considered as a generalization in understanding the behavior of sand under cyclic loading. There are two distinct mechanisms that aŠect the cyclic resistance of sand (Unno et al, 2008;Okamura and Noguchi, 2009). One is the eŠect of increasing the average volume compressibility in a mixture of air and water as the degree of air injection increases because the compressibility of air is much higher than that of water.…”

Section: Partial Saturationmentioning

confidence: 99%

Soils and Foundations During Earthquakes

Iai

Ichii

2010

Soils and Foundations

View full text Add to dashboard Cite

This paper provides an overview of the modern understanding of the behavior of soils and foundations during an earthquake based on the papers published in Soils and Foundations over the lastˆfty years. The most fundamental issues in geotechnical earthquake engineering are the non-linearity of soil under cyclic loading and its implications on the seismic performance of geotechnical structures. The non-linearity of granular materials is essentially anisotropic, whereas the linear or equivalent linear model often used in conventional practices is isotropic. The non-linearity of dry soil is characterized by the diŠerence between the peak and residual strengths, and the increased awareness of the implications of this diŠerence over time has allowed for the development of a generalized methodology for evaluating active earth pressures. The non-linearity of saturated soil under undrained cyclic shear diŠers fundamentally from that of dry soil, with saturated soil capable of mobilizing 100z of the shear strain in the double amplitude. The cyclic behavior of saturated soil under initial shear is typical of most seismic behaviors of geotechnical structures, including embankments, caisson quay walls, and underground structures. The liquefaction-induced ‰ow failure of geotechnical structures is associated with the steady state of sand in the order of 10 kPa. However, the challenge in the coming decades will be to evaluate the combined eŠects due to cyclic loading and the steady state. Moreover, the eŠects of pore water migration are signiˆcant in the case of highly permeable geotechnical materials when evaluating settlement of the ground or addressing inter-layered structures of clay and sand. Although current research is elucidating the mechanics of partially saturated sands, the new challenge is to understand combined hazards, such as a combination of earthquake motions and tsunamis. Thus, new approaches and technologies need to be developed.

show abstract

Simulation of liquefaction of unsaturated soil using critical state soil model

Komolvilas

Kikumoto

2017

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

Summary Several researchers have reported that the mean effective stress of unsaturated soils having a relatively high degree of saturation gradually decreases under fully undrained cyclic loading conditions, and such soils can be finally liquefied like saturated soils. This paper describes a series of simulations of fully undrained cyclic loading on unsaturated soils, conducted using an elastoplastic model for unsaturated soils. This model is a critical state soil model formulated using effective stress tensor for unsaturated soils, which incorporates the following concepts: (a) the volumetric movement of the state boundary surface containing the critical state line owing to the variation in the degree of saturation; (b) the soil water characteristic curve considering the effects of specific volume and hydraulic hysteresis; and (c) the subloading surface concept for considering the effect of density. Void air is assumed to be an ideal gas obeying Boyle's law. The proposed model is validated through comparisons with past results. The simulation results show that the proposed model properly describes the fully undrained cyclic behavior of unsaturated soils, such as liquefaction, compression, and an increase in the degree of saturation. Finally, the effects of the degree of saturation, void ratio, and confining pressure on the cyclic strength of unsaturated soils are described by the simulation results. The liquefaction resistance of unsaturated soils increases as the degree of saturation and the void ratio decrease, and as the confining pressure increases. Furthermore, the degree of saturation has a greater effect on the liquefaction resistance than the confining pressure and void ratio. Copyright © 2017 John Wiley & Sons, Ltd.

show abstract

Liquefaction Resistances of Unsaturated Non-Plastic Silt

Cited by 45 publications

References 18 publications

Fully undrained cyclic loading simulation on unsaturated soils using an elastoplastic model for unsaturated soils

Fully undrained cyclic loading simulation on unsaturated soils using an elastoplastic model for unsaturated soils

Soils and Foundations During Earthquakes

Simulation of liquefaction of unsaturated soil using critical state soil model

Contact Info

Product

Resources

About