scholarly journals ESTIMATION OF INITIAL VOID RATIO OF CONSOLIDATED CLAY BASED ON ONE-DIMENSIONAL CONSOLIDATION THEORY

2018 ◽  
Vol 14 (46) ◽  
Author(s):  
Yuko Ishida
Keyword(s):  
Void Ratio ◽  
One Dimensional ◽  
Consolidation Theory ◽  
Initial Void Ratio

scholarly journals One-dimensional large-strain thaw consolidation using nonlinear effective stress – void ratio – hydraulic conductivity relationships

2018 ◽  
Vol 55 (3) ◽  
pp. 414-426 ◽  
Author(s):  
Simon Dumais ◽  
Jean-Marie Konrad
Keyword(s):  
Heat Transfer ◽  
Hydraulic Conductivity ◽  
Effective Stress ◽  
Void Ratio ◽  
Moving Boundary ◽  
Initial Conditions ◽  
Large Strain ◽  
One Dimensional ◽  
Consolidation Theory ◽  
Thaw Consolidation

A one-dimensional model for the consolidation of thawing soils is formulated in terms of large-strain consolidation and heat-transfer equations. The model integrates heat transfer due to conduction, phase change, and advection. The hydromechanical behaviour is modelled by large-strain consolidation theory. The equations are coupled in a moving boundary scheme developed in Lagrangian coordinates. Finite strains are allowed and nonlinear effective stress – void ratio – hydraulic conductivity relationships are proposed to characterize the thawing soil properties. Initial conditions and boundary conditions are presented with special consideration for the moving boundary condition at the thaw front developed in terms of large-strain consolidation. The proposed model is applied and compared with small-strain thaw consolidation theory in a theoretical working example of a thawing fine-grained soil sample. The modelling results are presented in terms of temperature, thaw penetration, settlements, void ratio, and excess pore-water pressures.

scholarly journals COMPRESSIBILITY BEHAVIOUR OF COMPACTED SOILS – HYPERBOLIC MODELLING

2020 ◽  
Author(s):  
U. Venkata Ratnam ◽  
K. Nagendra Prasad
Keyword(s):  
Void Ratio ◽  
Model Parameters ◽  
Initial State ◽  
Compacted Soils ◽  
One Dimensional ◽  
Initial Void Ratio ◽  
Two Samples ◽  
Earth Structures ◽  
Hyperbolic Behavior ◽  
Engineering Projects

Compacted soils constitute most engineering projects such as earth dams,embankments, pavements, and engineered slopes because of their high shear strengthand low compressibility. The compressibility behavior of compacted soils is a key soilparameter in the design of earth structures but it is not determined correctly owing topartly saturated state. The compressibility of compacted soils can be better evaluatedunder the framework of hyperbolic behavior. One dimensional Consolidation tests oncompacted specimens were conducted using conventional oedometer apparatus underconstant water content condition. Tests were conducted by compact the soil specimensat respective optimum moisture contents for eight different soil samples, of varyinggrain size characteristics and consistency limits, collected from Tirupati Region. Themain objective of this study is to examine the compressibility behavior of compactedsoils to propose a phenomenological model. It is observed that the compressibilitybehavior can be captured by hyperbolic modeling with model parameters involved inthe behavior being initial void ratio, e0, representing the initial state of soil and otherhyperbolic constants linked to this state. The data of 6 samples were used fordeveloping the model and the data of remaining two samples were used for predictingthe observed response from the model proposed. The data of published literature hasalso been used to predict the experimental behavior to bring out the merits of themodel proposed.

scholarly journals Post-liquefaction reconsolidation of sand

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150745 ◽  
Author(s):  
O. Adamidis ◽  
G. S. P. Madabhushi
Keyword(s):  
Void Ratio ◽  
One Dimensional ◽  
Geotechnical Centrifuge ◽  
Significant Damage ◽  
Pore Water Pressures ◽  
The One ◽  
Crucial Parameter ◽  
Excess Pore ◽  
Good Agreement ◽  
Made In

Loosely packed sand that is saturated with water can liquefy during an earthquake, potentially causing significant damage. Once the shaking is over, the excess pore water pressures that developed during the earthquake gradually dissipate, while the surface of the soil settles, in a process called post-liquefaction reconsolidation. When examining reconsolidation, the soil is typically divided in liquefied and solidified parts, which are modelled separately. The aim of this paper is to show that this fragmentation is not necessary. By assuming that the hydraulic conductivity and the one-dimensional stiffness of liquefied sand have real, positive values, the equation of consolidation can be numerically solved throughout a reconsolidating layer. Predictions made in this manner show good agreement with geotechnical centrifuge experiments. It is shown that the variation of one-dimensional stiffness with effective stress and void ratio is the most crucial parameter in accurately capturing reconsolidation.

scholarly journals Prediction of the Void Ratio Parameter in Mineral Tailings Using Gene Expression Programming

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ali Akbar Heshmati R. ◽  
Hossein Salehzadeh ◽  
Mehdi Shahidi
Keyword(s):  
Gene Expression ◽  
Void Ratio ◽  
Gene Expression Programming ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Physical Parameters ◽  
Experimental Database ◽  
Initial Void Ratio ◽  
Different Sources ◽  
Initial Prediction

Mineral tailing deposits are one of the most important issues in the field of geotechnical engineering. The void ratio of mineral tailings is an essential parameter for investigating the geotechnical behavior of tailings. However, there has not yet been a comprehensive empirical formulation for initial prediction of the void ratio of mineral tailings. In this study, the void ratio of various types of mineral waste is estimated by using gene expression programming (GEP). Therefore, taking into consideration the effective physical parameters that affect the estimation of this parameter, eight different models are presented. A reliable experimental database collected from different sources in the literature was applied to develop the GEP models. The performance of the developed GEP models was measured based on coefficient of determination (R2), mean absolute error (MAE), and root mean square error (RMSE). According to the results, the model with effective stress σ ′ , initial void ratio (e0), and parameters of R2 = 0.92, MAE = 0.109, and RMSE = 0.180 performed the best. Finally, a new empirical formulation for the initial prediction of the void ratio parameter is proposed based on the aforementioned analyses.

The Duncan-Chang Model Parameters for Municipal Solid Waste

2011 ◽  
Vol 48-49 ◽  
pp. 1235-1240
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu
Keyword(s):  
Theoretical Analysis ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Void Ratio ◽  
Practical Method ◽  
Model Parameters ◽  
Mechanical Parameters ◽  
Initial Void Ratio ◽  
The Relationship ◽  
Chang Model

By theoretical analysis and laboratory test, the model parameters of Duncan-Chang for municipal solid waste have been studied. To obtain the mechanical parameters, a new simple and practical method has been established. Research results show that the damage ratio is 0.6, parameter n is about 1.05, parameter F varies between 0 and 0.1, and parameter G varies between 0.3 and 0.4. Besides, the relationship between parameter k and the initial void ratio is linear, and the slope of the line is 5.0.

Application of Terzaghi's consolidation theory to nearly saturated soils

1994 ◽  
Vol 31 (2) ◽  
pp. 311-317 ◽  
Author(s):  
Hans H. Vaziri ◽  
Harold A. Christian
Keyword(s):  
Unsaturated Soils ◽  
Measured Data ◽  
One Dimensional ◽  
Deformation Response ◽  
Consolidation Theory ◽  
Modified Equations ◽  
Consolidation Coefficient ◽  
Soil Skeleton ◽  
Oedometer Tests ◽  
Compressibility Characteristics

Terzaghi's one-dimensional consolidation theory is modified to account for the compressibility of fluid and solid phases. The proposed modified equations can be used to analyze the consolidation response of unsaturated soils over the saturation range where the gases remain in an occluded form (generally within a range between 80 and 100aturation); however, such applications are subject to the same limitations and idealizations implicit in Terzaghi's classical consolidation theory. The purpose of this note, therefore, is to offer a simple solution and not to unravel the complexities involved in general analysis of flow and deformation response of unsaturated soils. The proposed approach involves defining the consolidation coefficient, and hence the time factor, in terms of an equivalent fluid compressibility. This equivalent fluid is assumed to represent the compressibility characteristics of all the compressible phases that constitute the soil skeleton. The proposed generalized form of Terzaghi's consolidation equations is shown to qualitatively capture the consolidation behaviour of unsaturated soils. To test the validity of the formulations presented, one-dimensional oedometer tests were performed on specimens of Lantz clay that had been prepared at different saturation levels; satisfactory agreement was achieved between the theoretical and measured data at two states of saturation. Key words : consolidation, theoretical solutions, oedometer test, compressible fluid, occluded gas.

Study on the Compressibility of the Silt in Hangzhou, China

2013 ◽  
Vol 419 ◽  
pp. 853-857
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu ◽  
Cha Wang
Keyword(s):  
Laboratory Tests ◽  
Void Ratio ◽  
Soil Mechanics ◽  
Soil Samples ◽  
Compression Index ◽  
Uniformity Coefficient ◽  
Initial Void Ratio ◽  
Natural Density ◽  
Engineering Parameters ◽  
The Relationship

To investigate the compressibility of the silt, three soil samples are collected from Xiasha zone, Hangzhou, Zhejiang Province, China. The geotechnical engineering parameters of the silt soil are measured in the soil mechanics laboratory. Tests results show that the uniformity coefficient of the silt is 13.6, the natural density is 1.96t/m3, the moisture content is 17.0%, the plasticity index is 9.4, the compression coefficient varies from 0.06 to 0.40MPa-1, and the compression index varies from 0.015 to 0.108. Finally, the properties of the compression are studied, and find that the compressibility of the silt soil is very large, and the relationship between the initial void ratio and the logarithm pressure is linear.

Experimental Study on Shear Strength Considering Initial Void Ratio and Plasticity Index

2013 ◽  
Vol 405-408 ◽  
pp. 63-67
Author(s):  
Xing Chen Wang ◽  
Ri Qing Xu ◽  
Jian Feng Zhu
Keyword(s):  
Shear Strength ◽  
Void Ratio ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Plasticity Index ◽  
Test Results ◽  
Compression Tests ◽  
Functional Relationships ◽  
Initial Void Ratio

A series of drained triaxial compression tests under different conditions were performed to quantitatively study the influence of the initial void ratio and plasticity index on the shear strength of remolded saturated clays. The test results show that both the peak stress friction angle and peak deviatoric stress decrease with increasing initial void ratio and plasticity index of the soil under the same confining pressure; whereas, they increase with increasing confining pressure of the soil under the same initial void ratio and plasticity index. A new synthesized physical parameter λ, which simultaneously represent both the type and the condition of remolded saturated clays, is defined based on the test results in this work. The functional relationships among the parameters φd and peak deviatoric stress in Mohr-Coulomb equation and the parameter λ are established to develop a modified Mohr-Coulomb equation by considering physical properties of soil. In this equation, only two input parameters, i.e., λ and the confine pressure, are needed to predict the shear strength of the soil. In order to check the accuracy of the proposed equation, laboratory tests were conducted to evaluate against the predicted results. The results show that the peak shear strength of remolded saturated clays can be well described by the proposed equation. Key words: shear strength; Mohr-Coulomb equation; remolded saturated clays; initial void ratio; plasticity index.

scholarly journals Effect of Vertical Pressure on Horizontal and Vertical Permeability of Soil and Effect of Surcharge Pressure on 3D Consolidation of Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Arpan Laskar ◽  
Sujit Kumar Pal
Keyword(s):  
Soil Properties ◽  
Three Dimensional ◽  
Vertical Pressure ◽  
Soil Layers ◽  
One Dimensional ◽  
Consolidation Theory ◽  
Vertical Permeability ◽  
Homogeneous Soil ◽  
Soil Changes

Permeability and consolidation of soil are known as the most variable soil properties. The values of permeability and consolidation of soil may vary with depth even in case of homogeneous soil layers, and because of that, the determination of appropriate values of permeability and consolidation is a complex and complicated engineering task. In this study, horizontal and vertical permeability apparatus and a 3D (three-dimensional) consolidation apparatus are developed to determine the effects of vertical pressure on horizontal and vertical permeability and the effects of vertical surcharge pressures on three-dimensional consolidation of soil. A series of horizontal and vertical permeability tests of soil under different vertical pressures and a series of 3D consolidation tests under different surcharge pressures are performed. From the study, it is observed that the horizontal and vertical permeability of soil changes with the changes in vertical pressures, and 3D consolidation of soil also changes with the changes in surcharge pressures. The horizontal and vertical permeability values obtained from the newly developed horizontal and vertical permeability apparatus are used in Terzaghi’s one-dimensional consolidation theory to find out the consolidation characteristics of the soil, and it is compared with the results obtained from the newly developed 3D consolidation apparatus.

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