scholarly journals Influence of Initial Void Ratio on Critical State Behaviour of Poorly Graded Fine Sands

2020 ◽  
Vol 50 (5) ◽  
pp. 689-699
Author(s):  
Abdullah Ekinci ◽  
Mohamad Hanafi ◽  
Pedro Miguel Vaz Ferreira
Keyword(s):  
Critical State ◽  
Void Ratio ◽  
Initial Void Ratio ◽  
State Behaviour

Yield strength ratios, critical strength ratios, and brittleness of sandy soils from laboratory tests

2011 ◽  
Vol 48 (3) ◽  
pp. 493-510 ◽  
Author(s):  
Abouzar Sadrekarimi ◽  
Scott M. Olson
Keyword(s):  
Yield Strength ◽  
Critical State ◽  
Void Ratio ◽  
Triaxial Compression ◽  
Silty Sand ◽  
Strength Ratio ◽  
Critical Strength ◽  
Initial Void Ratio ◽  
Ring Shear ◽  
Particle Damage

In this study, we performed 26 undrained triaxial compression and 32 constant-volume ring shear tests on two clean sands and one silty sand. We then used these results to evaluate the critical states, and shear strength ratios mobilized at yield and at critical state. We obtained yield strength ratios that ranged from 0.16 to 0.32 and from 0.20 to 0.35 in triaxial compression and ring shear, respectively. Critical strength ratios mobilized prior to particle damage ranged from 0.01 to 0.26 in triaxial compression and from 0.04 to 0.22 in ring shear. Particle damage and shear displacement increased the slopes of the critical-state lines during ring shear testing, and consequently the critical strength ratios incorporating particle damage decreased from 0.02 to 0.12. In addition, specimen brittleness (before particle damage) increases with initial void ratio and state parameter and is affected by initial fabric and particle shape. However, particle damage and crushing considerably increases sand brittleness, making it essentially independent of initial void ratio. A unique relation is found between sand brittleness and critical strength ratio independent of sand type, mode of shear, fabric, and particle damage, which indicates an upper bound critical strength ratio of about 0.3 for mildly contractive sands.

Soil mechanics: breaking ground

2007 ◽  
Vol 365 (1861) ◽  
pp. 2985-3002 ◽  
Author(s):  
Itai Einav
Keyword(s):  
Grain Size ◽  
Critical State ◽  
Void Ratio ◽  
Soil Mechanics ◽  
Constitutive Models ◽  
Energy Balance Equation ◽  
Constitutive Modelling ◽  
Alternative Theory ◽  
Fitting Parameters ◽  
Cam Clay

In soil mechanics, student's models are classified as simple models that teach us unexplained elements of behaviour; an example is the Cam clay constitutive models of critical state soil mechanics (CSSM). ‘Engineer's models’ are models that elaborate the theory to fit more behavioural trends; this is usually done by adding fitting parameters to the student's models. Can currently unexplained behavioural trends of soil be explained without adding fitting parameters to CSSM models, by developing alternative student's models based on modern theories? Here I apply an alternative theory to CSSM, called ‘breakage mechanics’, and develop a simple student's model for sand. Its unique and distinctive feature is the use of an energy balance equation that connects grain size reduction to consumption of energy, which enables us to predict how grain size distribution (gsd) evolves—an unprecedented capability in constitutive modelling. With only four parameters, the model is physically clarifying what CSSM cannot for sand: the dependency of yielding and critical state on the initial gsd and void ratio.

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.

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.

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