An oedometer test study on the preconsolidation stress of glaciomarine clays

2003 ◽  
Vol 40 (5) ◽  
pp. 857-872 ◽  
Author(s):  
J L.H Grozic ◽  
T Lunne ◽  
S Pande
Keyword(s):  
Stress History ◽  
Traditional Methods ◽  
Testing Procedures ◽  
Oedometer Test ◽  
Test Study ◽  
Using Data ◽  
Plastic Clays ◽  
Disturbed Soils ◽  
Oedometer Tests ◽  
Test Stress

Stress history is usually determined by interpreting the results of oedometer tests to obtain the preconsolidation stress using traditional methods such as those proposed by Casagrande and Janbu. Both these methods are based on the assumption that the soil experiences a change in stiffness, from a stiff response to a soft response, close to the preconsolidation stress. Disturbed soils, however, especially overconsolidated clays of low plasticity, exhibit a soft response at low stresses, thereby making the interpretation of oedometer tests using traditional methods extremely difficult. Using data mainly from the Haltenbanken area, offshore Norway, a study was undertaken to investigate the various methods and testing procedures available to determining stress history. Oedometer verification tests were also performed on reconstituted specimens to compare interpreted values with the actual applied preconsolidation stress. This paper describes the results of the study by illustrating the variation in the interpretation methods and testing procedures used to determine preconsolidation stress.Key words: preconsolidation stress, yield stress, overconsolidated, low plastic clays, oedometer test, stress history.

In situ estimation of the coefficient of consolidation in clays

1990 ◽  
Vol 27 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Mohammed G. Kabir ◽  
Alan J. Lutenegger
Keyword(s):  
Key Words ◽  
Pore Pressure ◽  
Reference Values ◽  
Time Factors ◽  
In Situ Tests ◽  
Coefficient Of Consolidation ◽  
Oedometer Test ◽  
Undisturbed Samples ◽  
Oedometer Tests

An investigation was conducted to demonstrate the applicability of cylindrical piezocone and flat piezoblade tests for providing reliable estimates of the coefficient of consolidation in clays. Coefficients of consolidation were calculated from piezocone dissipation tests for different degrees of consolidation using theoretical time factors to provide a comparison with laboratory oedometer tests. Three techniques were developed to calculate the coefficient of consolidation from piezoblade dissipation tests. Results from in situ pore pressure dissipation tests were compared with laboratory oedometer tests performed on undisturbed samples oriented in both the vertical and horizontal directions, to provide reference values of cv and ch. The results of investigations conducted at several clay sites are presented. Key words: in situ tests, piezocone, piezoblade, coefficient of consolidation, oedometer test, clays.

Volume change indices during loading and unloading of an unsaturated soil

1992 ◽  
Vol 29 (2) ◽  
pp. 195-207 ◽  
Author(s):  
D. Y. F. Ho ◽  
D. G. Fredlund ◽  
H. Rahardjo
Keyword(s):  
Soil Properties ◽  
Key Words ◽  
Volume Change ◽  
Unsaturated Soil ◽  
Constitutive Relations ◽  
Change Theory ◽  
Glacial Till ◽  
Testing Procedures ◽  
Loading And Unloading ◽  
Oedometer Tests

The paper presents the volume change theory and the designation of associated soil properties that must be measured for an unsaturated soil. The equipment required for the measurement of each of the relevant volume relationships is described. Several testing procedures for obtaining the volume change indices during loading and unloading of an unsaturated soil are presented. Typical results from loading and unloading tests on compacted silt and compacted glacial till specimens are presented and analyzed. The analysis is given in order to illustrate the application of the volume change theory to practical problems. Key words : unsaturated soil, volume change indices, constitutive relations, coefficients of volume change, oedometer tests.

scholarly journals Experimental and analytical investigations of volume change behaviour of saturated expansive soils in oedometer test

2019 ◽  
Vol 92 ◽  
pp. 10006
Author(s):  
Misa Hiraga ◽  
Hiroyuki Kyokawa ◽  
Junichi Koseki
Keyword(s):  
Expansive Soils ◽  
Swelling Behaviour ◽  
Oedometer Test ◽  
Lower Shear ◽  
Lateral Contraction ◽  
Mechanical Behaviours ◽  
Water Saturated ◽  
Electrochemical Phenomena ◽  
Mechanical Consolidation ◽  
Oedometer Tests

The chemical and mechanical behaviours of saturated bentonite were experimentally and analytically investigated. A series of oedometer tests on saturated bentonite was conducted. By replacing the cell fluid during the oedometer test, one-dimensional osmotic consolidation and swelling behaviour were observed. The experimental results were simulated numerically using a constitutive model by considering the influence of electrochemical phenomena of clay mineral crystals on the macrostructural behaviour. It was concluded that the typical mechanical swellability of water-saturated bentonite in oedometer test is affected by a positive dilatancy behaviour due to the lower shear strength. After the osmotic consolidation test, a lateral contraction of the specimen in the oedometer was observed; this affected the compressibility during the subsequent mechanical consolidation. It was also concluded that the concentration of Na+ in the pore fluid affects the specific mechanical properties of bentonite.

Reliability of Alternative Trunk Endurance Testing Procedures Using Clinician Stabilization Vs. Traditional Methods

2010 ◽  
Vol 24 (3) ◽  
pp. 730-736 ◽  
Author(s):  
Michael P Reiman ◽  
Amber D Krier ◽  
Julie A Nelson ◽  
Michael A Rogers ◽  
Zachariah O Stuke ◽  
...  
Keyword(s):  
Traditional Methods ◽  
Testing Procedures ◽  
Endurance Testing

scholarly journals Elastoplastical Analysis of the Interface between Clay and Concrete Incorporating the Effect of the Normal Stress History

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Zhao Cheng ◽  
Zhao Chunfeng ◽  
Gong Hui
Keyword(s):  
Normal Stress ◽  
Load Transfer ◽  
Shear Behaviour ◽  
Model Parameters ◽  
Stress History ◽  
Hardening Parameter ◽  
Using Data ◽  
Energy Dissipated ◽  
Interaction Problem ◽  
Soil Interface

The behaviour of the soil-structure interface is crucial to the design of a pile foundation. Radial unloading occurs during the process of hole boring and concrete curing, which will affect the load transfer rule of the pile-soil interface. Through large shear tests on the interface between clay and concrete, it can be concluded that the normal stress history significantly influences the shear behaviour of the interface. The numerical simulation of the bored shaft-soil interaction problem requires proper modelling of the interface. By taking the energy accumulated on the interface as a hardening parameter and viewing the shearing process of the interface as the process of the energy dissipated to do work, considering the influence of the normal stress history on the shearing rigidity, a mechanical model of the interface between clay and concrete is proposed. The methods to define the model parameters are also introduced. The model is based on a legible mathematical theory, and all its parameters have definite physical meaning. The model was validated using data from a direct shear test; the validation results indicated that the model can reproduce and predict the mechanical behaviour of the interface between clay and concrete under an arbitrary stress history.

scholarly journals Determination of Creep Properties of Clays from VRS Oedometer Tests

2019 ◽  
Vol 38 (2) ◽  
pp. 1857-1871 ◽  
Author(s):  
Tim Tapani Länsivaara
Keyword(s):  
Soft Clay ◽  
Complex Stress ◽  
Soil Parameters ◽  
Rate Variation ◽  
Additional Parameter ◽  
Creep Properties ◽  
Oedometer Test ◽  
Wide Range ◽  
Oedometer Tests

AbstractThe determination of creep properties still relies almost entirely on the incrementally loaded oedometer test introduced about 100 years ago. Although the simplicity of the test assures a robust evaluation of soil parameters, it also introduces some shortcomings like discontinuity of the evaluated parameters and the long duration of the test. In this study, the performance of the variable rate of strain (VRS) oedometer test for determination of creep properties of a sensitive soft clay is studied. The results from a comprehensive test series of VRS oedometer tests on a soft sensitive clay is presented. Three different setups for the strain rate variation were used, and each test was repeated thrice. The tests showed good consistency and yielded equal creep parameters compared to values from traditional incrementally loaded (IL) oedometer tests. The tests further verified that it is possible to describe the complex stress dependency of creep parameters with just one additional parameter to the primary deformation parameters. Compared to the IL tests, the VRS tests offers a faster determination and continuous creep properties for a wide range of stress.

scholarly journals Observation-Oriented Modeling: Going Beyond “Is It All a Matter of Chance”?

2016 ◽  
Vol 77 (5) ◽  
pp. 855-867 ◽  
Author(s):  
James W. Grice ◽  
Maria Yepez ◽  
Nicole L. Wilson ◽  
Yuichi Shoda
Keyword(s):  
Null Hypothesis ◽  
Model Building ◽  
Pattern Detection ◽  
Significance Testing ◽  
Null Hypothesis Significance Testing ◽  
Traditional Methods ◽  
Novel Approach ◽  
Observation Oriented Modeling ◽  
Using Data

An alternative to null hypothesis significance testing is presented and discussed. This approach, referred to as observation-oriented modeling, is centered on model building in an effort to explicate the structures and processes believed to generate a set of observations. In terms of analysis, this novel approach complements traditional methods based on means, variances, and covariances with methods of pattern detection and analysis. Using data from a previously published study by Shoda et al., the basic tenets and methods of observation-oriented modeling are demonstrated and compared with traditional methods, particularly with regard to null hypothesis significance testing.

Statistical relationships between piezocone measurements and stress history of clays

1996 ◽  
Vol 33 (3) ◽  
pp. 488-498 ◽  
Author(s):  
B SY Chen ◽  
P W Mayne
Keyword(s):  
Cone Penetration ◽  
Stress History ◽  
Statistical Correlations ◽  
Cone Tip Resistance ◽  
Clay Deposits ◽  
Preconsolidation Pressure ◽  
Tip Resistance ◽  
History Of ◽  
Statistical Relationships ◽  
Oedometer Tests

A database containing piezocone soundings from 205 clay sites around the world has been compiled for the calibration of an analytical cone penetration model and the development of statistical correlations. Yield stresses from laboratory oedometer tests were used as reference values for determining the stress history of natural clay deposits. Both simple and multiple regression analyses were performed on these data to evaluate correlative trends. Several simplified empirical relationships were identified for use in practice with the most reliable in relating preconsolidation stress to net cone tip resistance. Key words: cone tip resistance, overconsolidation ratio (OCR), preconsolidation pressure, piezocone, statistical relationships, stress history.

scholarly journals A NEW GEOGRAPHIC CONTEXT MEASURE TO SIMILARITY ASSESSMENT BASED ON THE SHAPE CONTEXT DESCRIPTOR

2020 ◽  
Vol XLIII-B4-2020 ◽  
pp. 513-517
Author(s):  
E. M. A. Xavier ◽  
M. A. Ureña-Cámara ◽  
F. J. Ariza-López
Keyword(s):  
Remote Sensing ◽  
Data Integration ◽  
Feasible Solution ◽  
Shape Context ◽  
Matching Method ◽  
Traditional Methods ◽  
Geographic Context ◽  
Integration Techniques ◽  
Geospatial Datasets ◽  
Using Data

Abstract. Nowadays there are many geospatial datasets available for the same area. This large availability is derivative from the advances in remote sensing processes, which includes the popularization of drones and the increasing number of satellite platforms. These data are built by distinct producers, with different requirements. It is fair presume that a more complete version of these datasets can be created using data integration techniques. Among them we can find the map conflation methods, in which the first phase often begins with an alignment between the datasets assessed. The procedure of find these correspondences between geospatial datasets is called matching. In this study we present a new geographic context measure that can be used to implement a new matching method at the feature level. This new measure is based on the shape context descriptor proposed by Belongie. The experiments showed that our approach is a feasible solution, which is less sensible to data disturbance then other traditional methods.

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