Constitutive modelling of Otaniemi soft clay in both natural and reconstituted states

Yang, Chao; Liu, Xiliang; Liu, Xianfeng; Yang, Cheng‐Hong; Carter, John

doi:10.1016/j.compgeo.2015.07.018

“…where is a weighting parameter. This type of destructuration laws considering three yield surfaces has been applied in many models (Callisto and Calabresi 1998, Hinchberger et al 2010, Panayides et al 2012, Liu et al 2013, Yang et al 2015.…”

Section: Baudet and Stallebrass's Destructuration Modelmentioning

confidence: 99%

A Deviatoric Softening Model to Simulate Compressibility Properties of Soft Clays

Cong¹

2021

Preprint

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Soft clays are often associated with high compressibility due to their high void ratio, low shear strength, and creep behavior. Structures built on top of it can experience excessive settlement issues over a long period of time. The prediction of these settlements has attracted attentions from many researchers for over a century, but accurately predicting them still remains a difficult issue due to complex properties of soft clays, including plasticity, viscosity, anisotropy, soil structure and so forth. Therefore, studying the compressibility of soft clay is of significant importance. This dissertation aims to investigate the influence of plastic deviatoric strains on the compressibility of soft clays. First of all, the dissertation reviews a number of published incremental anisotropic consolidation tests on Finnish clays. The results demonstrate the dependence of soil compressibility on stress ratios. Based on the result, a modified yield surface size deviatoric softening law has been introduced. This softening law describes yield surface softening to be related to plastic deviatoric strain increments. Secondly, a new model named MEVP-DS, has been incorporated into the framework of Yin’s elaso-viscoplastic model to consider deviatoric softening, destructuration, and yield surface anisotropy of soft clay. Furthermore, the verification of MEVP-DS has been done through three phases. Phase one is the simulation of published incremental anisotropic consolidation tests on intact Finnish clay samples. The model results demonstrate MEVP-DS successfully captures the soil compressibility in response to different stress ratios. Phase two is the application of MEVP-DS in modeling 1-D consolidation tests on sensitive Champlain Sea clay. Model results highlight that using MEVP-DS is beneficial for predicting the compressibility and excess pore pressure response of the clay subject to constant rate of strain loading. Phase three is the application of MEVP-DS in simulating a real embankment dam on Champlain Sea clay. MEVP-DS not only simulates 40-year settlement measurements of the dam reasonably well, but also improves the prediction of lateral spreading of the dam. In summary, the MEVP-DS model proposed in this dissertation has shown to improve the simulation of soil compressibility of soft clays subject to 1-D, anisotropic and more complicated loading conditions.

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“…where is a weighting parameter. This type of destructuration laws considering three yield surfaces has been applied in many models (Callisto and Calabresi 1998, Hinchberger et al 2010, Panayides et al 2012, Liu et al 2013, Yang et al 2015.…”

Section: Baudet and Stallebrass's Destructuration Modelmentioning

confidence: 99%

A Deviatoric Softening Model to Simulate Compressibility Properties of Soft Clays

Cong¹

2021

Preprint

0

View full text Add to dashboard Cite

Soft clays are often associated with high compressibility due to their high void ratio, low shear strength, and creep behavior. Structures built on top of it can experience excessive settlement issues over a long period of time. The prediction of these settlements has attracted attentions from many researchers for over a century, but accurately predicting them still remains a difficult issue due to complex properties of soft clays, including plasticity, viscosity, anisotropy, soil structure and so forth. Therefore, studying the compressibility of soft clay is of significant importance. This dissertation aims to investigate the influence of plastic deviatoric strains on the compressibility of soft clays. First of all, the dissertation reviews a number of published incremental anisotropic consolidation tests on Finnish clays. The results demonstrate the dependence of soil compressibility on stress ratios. Based on the result, a modified yield surface size deviatoric softening law has been introduced. This softening law describes yield surface softening to be related to plastic deviatoric strain increments. Secondly, a new model named MEVP-DS, has been incorporated into the framework of Yin’s elaso-viscoplastic model to consider deviatoric softening, destructuration, and yield surface anisotropy of soft clay. Furthermore, the verification of MEVP-DS has been done through three phases. Phase one is the simulation of published incremental anisotropic consolidation tests on intact Finnish clay samples. The model results demonstrate MEVP-DS successfully captures the soil compressibility in response to different stress ratios. Phase two is the application of MEVP-DS in modeling 1-D consolidation tests on sensitive Champlain Sea clay. Model results highlight that using MEVP-DS is beneficial for predicting the compressibility and excess pore pressure response of the clay subject to constant rate of strain loading. Phase three is the application of MEVP-DS in simulating a real embankment dam on Champlain Sea clay. MEVP-DS not only simulates 40-year settlement measurements of the dam reasonably well, but also improves the prediction of lateral spreading of the dam. In summary, the MEVP-DS model proposed in this dissertation has shown to improve the simulation of soil compressibility of soft clays subject to 1-D, anisotropic and more complicated loading conditions.

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“…The Yin et al_2011 model introduces 2 structure parameters to take into consideration the destructuration effect on the deformation of natural clays. Additionally, an elastic‐plastic model, ie, the Yang et al_2015 model, which can incorporate the structure effect of intact soft soil, is also investigated in this study.…”

Section: Review Of Time‐dependent Models and Bayesian Probabilistic Mmentioning

confidence: 99%

“…Many scholars believe that the total strain rate is divided into the elastic strain rate and the viscoplastic strain rate, and they have proposed different models to describe the viscoplastic strain rate for modeling the time‐dependent behavior of soft soils. In this study, 9 well‐known 1‐D compression models proposed by researchers (other works) for soft soils are briefly reviewed and assessed. The 9 models use the same equation to consider the elastic strain rate, which can be written as follows:

{\dot{ε}}_{z}^{e} = \frac{κ}{1 + e_{0}} \frac{{\overset{σ^{'}}{true}}_{z}}{σ_{z}^{'}},

where e 0 is the initial void ratio, κ is used to denote the elastic behavior of soil, and

σ_{z}^{'}

is the effective vertical stress.…”

Section: Review Of Time‐dependent Models and Bayesian Probabilistic Mmentioning

confidence: 99%

Effect of loading duration on uncertainty in creep analysis of clay

Tan

¹

,

Zhou

²

,

Yuen

³

2018

Num Anal Meth Geomechanics

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Summary Some studies suggest that creep parameters should be determined using a greater quantity of creep test data to provide more reliable prediction regarding the deformation of soft soils. This study aims to investigate the effect of loading duration on model updating. One‐dimensional consolidation data of intact Vanttila clay under different loading durations collected from the literature is used for demonstration. The Bayesian probabilistic method is used to identify all unknown parameters based on the consolidation data during the entire consolidation process, and their uncertainty can be quantified through the obtained posterior probability density functions. Additionally, the optimal models are also determined from among 9 model candidates. The analyses indicate that the optimal models can describe the creep behavior of intact soft soils under different loading durations, and the adopted method can evaluate the effect of loading duration on uncertainty in the creep analysis. The uncertainty of a specific model and its model parameters decreases as more creep data are involved in the updating process, and the updated models that use more creep data can better capture the deformation behavior of an intact sample. The proposed method can provide quantified uncertainty in the process of model updating and assist engineers to decide whether the creep test data are sufficient for the creep analysis.

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Constitutive modelling of Otaniemi soft clay in both natural and reconstituted states

Cited by 14 publications

References 29 publications

A Deviatoric Softening Model to Simulate Compressibility Properties of Soft Clays

A Deviatoric Softening Model to Simulate Compressibility Properties of Soft Clays

A Deviatoric Softening Model to Simulate Compressibility Properties of Soft Clays

Effect of loading duration on uncertainty in creep analysis of clay

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