Compression and consolidation characteristics of structured natural clay

2004 ◽  
Vol 41 (6) ◽  
pp. 1250-1258 ◽  
Author(s):  
J -C Chai ◽  
N Miura ◽  
H -H Zhu ◽  
Yudhbir
Keyword(s):  
Numerical Analysis ◽  
Void Ratio ◽  
Natural Clay ◽  
Hardening Law ◽  
Modified Cam Clay ◽  
Calculated Load ◽  
Natural Clays ◽  
Consolidation Behavior ◽  
Better Than ◽  
Cam Clay

The compression and consolidation behavior of some structured natural clays are discussed. It is shown that for some structured natural clays, the relation between void ratio (e) and mean effective stress (p′) is more linear in a ln(e + ec) – ln(p′) plot (where ec is a soil parameter) than in an e – ln(p′) plot. It is proposed that for structured natural clay with a sensitivity value greater than 4, a linear ln(e + ec) – ln(p′) relation can be used in settlement and consolidation calculation. The effect of introducing a linear ln(e + ec) – ln(p′) relation on the calculated load–settlement curve and consolidation behavior of structured clays is discussed. The linear ln(e + ec) – ln(p′) relation was incorporated into the modified Cam–clay model by modifying the hardening law of the model. It is shown that using the linear ln(e + ec) – ln(p′) relation simulated the consolidation behavior of the structured natural clays better than using the linear e – ln(p′) relation.Key words: structured natural clay, compression, consolidation, constitutive model, numerical analysis.

Numerical analysis of the breakwater construction of Sergipe Harbour, Brazil

1998 ◽  
Vol 35 (6) ◽  
pp. 1018-1031 ◽  
Author(s):  
Paulo José Brugger ◽  
Márcio de Souza Soares de Almeida ◽  
Sandro Salvador Sandroni ◽  
Willy Alvarenga Lacerda
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Shear Strain ◽  
Field Observations ◽  
Modified Cam Clay ◽  
Shear Strains ◽  
Horizontal Displacements ◽  
Undrained Creep ◽  
Excess Pore ◽  
Cam Clay

The numerical simulation of the breakwater construction at Sergipe Harbour, Brazil, is described and the results compared with instrumentation data. The numerical simulation was carried out in plane-strain conditions using the modified Cam-Clay model and the Biot consolidation theory. Field observations and the numerical simulation show that the horizontal displacements under the breakwater toe increase with time. This happens during the loading and consolidation stages. It is argued that the process does not necessarily derive only from undrained creep, since the model used does not simulate this phenomenon. The shear strains, measured by an inclinometer, increase more rapidly near the free-draining surfaces, in a process similar to the dissipation of excess pore pressure.Key words: clay, embankment, numerical analysis, shear strain, consolidation.

Hydraulic conductivity of contaminated natural clay directly below a domestic landfill

1987 ◽  
Vol 24 (3) ◽  
pp. 377-383 ◽  
Author(s):  
R. M. Quigley ◽  
F. Fernandez ◽  
E. Yanful ◽  
T. Helgason ◽  
A. Margaritis ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Heavy Metal Concentration ◽  
Natural Clay ◽  
Domestic Waste ◽  
Waste Landfill ◽  
Copper Zinc ◽  
Soluble Species ◽  
Natural Clays ◽  
Clay Barriers

The hydraulic conductivity of natural clays in the 1.5 m contamination zone below a 15 year old domestic waste landfill has been determined.Water-soluble contaminants such as chloride, sodium, and dissolved organic carbon have migrated about 1.0 m compared with only 15 cm for copper, zinc, iron, lead, and manganese. The migration, primarily by diffusion, has rendered the clay perfect for assessment of clay–leachate compatibility with respect to hydraulic conductivity, k.Oedometer tests on tube samples of the clay yielded k values of 1.4 × 10−8 cm/s with a slight decrease to about 1 × 10−8 cm/s in the upper 20 cm of clay at the waste–clay interface. Direct measurement of k on "undisturbed" tube samples, reconsolidated to their field stress state and permeated with pore fluid squeezed from adjacent contaminated samples, yielded values of 1.5 × 10−8 cm/s at 1 m depth decreasing to 0.75 × 10−8 cm/s at the interface.The decrease in k near the interface seems to correlate directly with increased pollutant concentration of soluble species, total heavy metal concentration, and a slight decrease in void ratio. The changes in k are so small, however, that for the test leachates and undisturbed test soils at this domestic waste site, it is concluded that the hydraulic conductivity has not changed significantly as a result of contamination. Key words: domestic waste, leachate, hydraulic conductivity, clay barriers, compatibility.

Research on the Prediction and Calculation Method of Settlement of Red Clay Foundation

2014 ◽  
Vol 998-999 ◽  
pp. 1444-1447
Author(s):  
Yuan Zhong Zhou ◽  
Xin Rong Liu ◽  
Yu Yu
Keyword(s):  
Finite Element ◽  
Finite Element Methods ◽  
Calculation Method ◽  
Geometric Nonlinearity ◽  
Red Clay ◽  
Modified Cam Clay ◽  
Deformation Behaviors ◽  
Oil Tank ◽  
Better Than ◽  
Cam Clay

A Modified Cam-Clay Model and finite element methods (FEM) are used in this paper to analyze the deformation and settlement of red clay foundation. The results show: (1)The deformation of oil tank foundation calculated is close to that measured and the effect of geometric nonlinearity is small. (2) Geometry of loading and level of stress have important effects on the deformation behaviors of red clay foundations. In practice the result of elastic-plastic FEM is much better than that of classical calculated methods (CCM).

Formability Analysis of Fukui Stretch-Drawing and Square Cup Drawing Using Strain and Stress Based Forming Limit Curves

2017 ◽  
Vol 751 ◽  
pp. 167-172 ◽  
Author(s):  
Sansot Panich ◽  
Nopparat Seemuang ◽  
Taratip Chaimongkon
Keyword(s):  
Flow Behavior ◽  
High Strength ◽  
Forming Limit ◽  
Forming Limit Curve ◽  
Yield Criteria ◽  
Hardening Law ◽  
Stress Curve ◽  
Strain Paths ◽  
Cup Drawing ◽  
Better Than

In this work, the experimental and numerical analyses of Forming Limit Curve (FLC) and Forming Limit Stress Curve (FLSC) for Advanced High Strength Steel (AHSS) sheet, grade JAC780Y, are performed. Initially, the FLC is experimentally determined by means of the Nakazima Stretch forming test. Subsequently, the FLSC of investigated steel was plastically calculated using the experimental FLC data. Different yield criteria including Hill48, and Yld89, are applied to describe plastic flow behavior of the AHS steel and Swift hardening law is taken into account. Hereby, influences of the constitutive yield models on the numerically determined FLSCs are evaluated regarding to those results from the experimental data. The obtained stress based forming limits are affected significantly by the yield criteria. Finally, the experimental and numerical formability analyses of Fukui stretch-drawing and square cup drawing tests are studied through FLC and FLSCs. It is observed that all stress based curves can be used very well to describe material formability of the examined steel compared to the strain based FLC. The strain based FLC depend on forming history and strain paths change. In the other hand, the stress based FLC do not depend on these issue. In this study, it can be concluded that the FLSCs could predict failure more realistically and better than the strain based FLC.

A New Elasto-Plastic Critical State Model RU+MCC for Overconsolidated Soil

2016 ◽  
Vol 837 ◽  
pp. 68-74
Author(s):  
Rafal Uliniarz
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
Small Strain ◽  
Computer Code ◽  
Constitutive Law ◽  
Isotropic Hardening ◽  
Loading Test ◽  
Modified Cam Clay ◽  
Soil Behaviour ◽  
Cam Clay

The paper presents a reasonably advanced constitutive law for soil – a hybrid of the Modified Cam Clay and a new RU development. The Modified Cam Clay model is an isotropic hardening elasto – plastic model originated by Burland in 1967 [1] within the critical state soil mechanics. This model describes realistically mechanical soil behaviour in normal consolidation states. The other one is designed to ensure more adequate soil responses to reloading paths, particularly in the range of small strains. The RU+MCC model has been implemented in the FEM computer code Z_SOIL.pc. To test the influence of the small strain nonlinearity on soil – structure interaction as well as to exhibit the ability of the proposed model to simulate realistically this effect, a comparative study based on the FEM solution has been carried out. As a benchmark a trial loading test of strip footing was used.

Some remarks on implicit integration of modified cam-clay model

2019 ◽  
pp. 297-304
Author(s):  
Aleksandar D. Spasojević ◽  
Dejan M. Divac ◽  
Nenad M. Šušić
Keyword(s):  
Implicit Integration ◽  
Clay Model ◽  
Modified Cam Clay ◽  
Cam Clay
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