A reexamination of the permeability index of clays

1993 ◽  
Vol 30 (1) ◽  
pp. 187-191 ◽  
Author(s):  
G. L. Sivakumar Babu ◽  
N. S. Pandian ◽  
T. S. Nagaraj
Keyword(s):  
Void Ratio ◽  
State Parameter ◽  
Paper Analysis ◽  
Liquid Limit ◽  
Test Results ◽  
Permeability Index ◽  
Initial Void Ratio ◽  
Generalized State ◽  
Marine Clays ◽  
Parameter Approach

The permeability index Ck, similar to the compression index, is the slope of the void ratio – coefficient of permeability relationship. Literature shows that, in general, for sensitive clays it can be related to initial void ratio by Ck = 0.5e0. The possibility of obtaining such a relationship for Cochin marine clays in terms of liquid limit void ratio is indicated in this paper. Analysis of permeability behaviour of Cochin marine clays and the test results available in published literature using generalized state parameter approach show that, in principle, these forms of equations for the permeability index are tenable, even though they were obtained based on experimental observation alone. Key words : permeability index, initial void ratio, void ratio at liquid limit, generalized state parameter approach.

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.

Estimation of some properties of Champlain clays with the Swedish fall cone

1977 ◽  
Vol 14 (4) ◽  
pp. 571-581 ◽  
Author(s):  
R. Garneau ◽  
J. P. LeBihan
Keyword(s):  
Void Ratio ◽  
Liquid Limit ◽  
Physical Characteristics ◽  
Unit Weight ◽  
Compression Index ◽  
Cone Penetration ◽  
Testing Procedures ◽  
Preconsolidation Pressure ◽  
Marine Clays

A large number of laboratory tests, carried out to determine index and physical characteristics of Champlain marine clays, using conventional testing procedures and the Swedish fall cone tests, have led to reliable relationships between the cone penetration and certain characteristics.The purpose of this study has been to establish a rapid method of estimating some index and physical characteristics of this clay. The method described in this paper allows the estimation of clay properties, such as liquid limit, compression index, preconsolidation pressure, undisturbed and remolded shear strength, sensitivity, water content, void ratio, and unit weight, within as little as half an hour and using a single undisturbed specimen. When testing according to conventional procedures, the determination of these characteristics takes several days or even weeks.This paper presents the method of estimation and the procedure used to establish the relationships between the results obtained by conventional methods and those derived using the Swedish fall cone.

Assessment of engineering properties of Bangkok clay

2007 ◽  
Vol 44 (2) ◽  
pp. 173-187 ◽  
Author(s):  
Suksun Horpibulsuk ◽  
Satoru Shibuya ◽  
Kittitep Fuenkajorn ◽  
Wanchai Katkan
Keyword(s):  
Shear Strength ◽  
Yield Stress ◽  
Void Ratio ◽  
State Parameter ◽  
Liquid Limit ◽  
Vertical Stress ◽  
Engineering Properties ◽  
Ideal Condition ◽  
Intrinsic State ◽  
Yield State

Due to the effect of structure, Bangkok clay is stable in a metastable state. Its void ratio, e, is the summation of the void ratio sustained by the intrinsic fabric, eR, and the additional void ratio due to the structure, es. The intrinsic state line (eR versus log σ′v, where σ′v is the effective vertical stress) is developed in terms of the void ratio at the liquid limit, eL. At the post-yield state, es is inversely proportional to σ′v. The residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress, is constant at about 0.20 for soft Bangkok clay and 0.12 for medium stiff Bangkok clay. From these findings and the ideal condition of zero compression at the pre-yield state, the field yield stress and field compression curve can be assessed. The undrained shear strength is directly related to the field yield stress, since both reflect the structure. The soil structure does not significantly influence the permeability. The permeability of the clay in structured and destructured states is identical under the same void ratio and can be determined from the generalized state parameter, e/eL. These observations result in a simple and practical method for assessment of the engineering properties of natural Bangkok clay.Key words: Bangkok clay, destructured state, compression, intrinsic state line, permeability, structured state, vane shear strength.

Modified Duncan-Chang Model Considering Physical Properties of Saturated Clays

2013 ◽  
Vol 416-417 ◽  
pp. 1746-1752
Author(s):  
Xing Chen Wang ◽  
Ri Qing Xu ◽  
Jing Lin Qian
Keyword(s):  
Physical Properties ◽  
Void Ratio ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Plasticity Index ◽  
Test Results ◽  
Stress Strain ◽  
Initial Void Ratio ◽  
Proposed Model ◽  
Chang Model

A series of undrained triaxial compression tests of saturated clays under different conditions were performed to study whether it is possible to determine parameters specifying Duncan-Chang model simply by using the physical parameters. The test results show that both the initial tangent modulus 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 with the same initial void ratio and plasticity index. A new synthesized physical parameter λ is defined based on the test results in this work. The functional relationships among the parameters K, peak deviatoric stress in Duncan-Chang model and the parameter λ are established to develop a modified Duncan-Chang model by considering physical properties of soil. In this model, only two input parameters, i.e., λ and the damage ratio Rf, are needed to predict the stress-strain relationships of the soil. In order to check the accuracy of the proposed model, laboratory tests were conducted to evaluate against the predicted results. The results show that the stress-strain relationships of saturated clays can be well described by the proposed model.

scholarly journals Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

2021 ◽  
Vol 13 (14) ◽  
pp. 7758
Author(s):  
Biao Qian ◽  
Wenjie Yu ◽  
Beifeng Lv ◽  
Haibo Kang ◽  
Longxin Shu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Void Ratio ◽  
Soil Mass ◽  
Direct Shear ◽  
Test Results ◽  
The Sustainable Development ◽  
Direct Shear Tests ◽  
Soil Cement ◽  
Nano Clay ◽  
New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

scholarly journals Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Soft Soil ◽  
Compressive Modulus ◽  
Engineering Properties ◽  
Test Results ◽  
Use Of Resources ◽  
One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

scholarly journals Compressibility behaviour of remoulded, fine-grained soils and correlation with index properties

2000 ◽  
Vol 37 (3) ◽  
pp. 712-722 ◽  
Author(s):  
A Sridharan ◽  
H B Nagaraj
Keyword(s):  
Liquid Limit ◽  
Plasticity Index ◽  
Engineering Properties ◽  
Test Results ◽  
Index Properties ◽  
Initial Water ◽  
Fine Grained ◽  
Wide Range ◽  
The Relationship ◽  
Water Contents

Correlating engineering properties with index properties has assumed greater significance in the recent past in the field of geotechnical engineering. Although attempts have been made in the past to correlate compressibility with various index properties individually, all the properties affecting compressibility behaviour have not been considered together in any single study to examine which index property of the soil correlates best with compressibility behaviour, especially within a set of test results. In the present study, 10 soils covering a sufficiently wide range of liquid limit, plastic limit, and shrinkage limit were selected and conventional consolidation tests were carried out starting with their initial water contents almost equal to their respective liquid limits. The compressibility behaviour is vastly different for pairs of soils having nearly the same liquid limit, but different plasticity characteristics. The relationship between void ratio and consolidation pressure is more closely related to the shrinkage index (shrinkage index = liquid limit - shrinkage limit) than to the plasticity index. Wide variations are seen with the liquid limit. For the soils investigated, the compression index relates better with the shrinkage index than with the plasticity index or liquid limit.Key words: Atterberg limits, classification, clays, compressibility, laboratory tests.

Determination of the Emission of Volatile Organic Compounds from Leather Seats in Environmental Test Chamber

2018 ◽  
Vol 768 ◽  
pp. 31-35
Author(s):  
Jin Wang ◽  
Zhen Zhu Ma ◽  
Lu Chen ◽  
Hong Juan Sun ◽  
Wu Kun Fan
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Test Chamber ◽  
Paper Analysis ◽  
National Standard ◽  
Test Results ◽  
Total Volatile Organic Compound ◽  
Volatile Organic ◽  
Environmental Test

With reference to the international standard ISO16000-9 and the national standard GB/T 31106-14, this paper has chosen leather seats as the research object in order to study the emission of volatile organic compounds (VOCs) and total volatile organic compound (TVOC). The test results show that about 21 species of VOCs released from the leather seats were measured, including several types of aldehydes, ketones, aromatic hydrocarbon ,hydrocarbon, lipids and so on.This paper analysis the possible sources of volatile organic compounds in leather seats as well.

Consolidation Properties of Ho Chi Minh City Soil, Vietnam

2020 ◽  
Vol 54 (1A) ◽  
pp. 1-10
Author(s):  
Vo Nhat Luan
Keyword(s):  
Void Ratio ◽  
Soft Soil ◽  
Liquid Limit ◽  
Ho Chi Minh City ◽  
Compression Index ◽  
Underground Structures ◽  
Compression Pressure ◽  
Coefficient Of Consolidation ◽  
Two Samples ◽  
Index Changes

This paper presents the experimental results of consolidation properties of soft soil in Ho Chi Minh City of Vietnam. Forty-two samples were collected from different locations and were determined in the laboratory by Oedometer test. The results showed that the coefficient of consolidation of soft soil varies from 0.052.10-3 to 3.3.10-3cm2/s, otherwise the compression index changes from 0.156 to 1.703, soil is in a normally consolidated or over the consolidated state. These properties also change differently with depth. It also indicated that the compressive index of soft soil has a fine linear relationship with the liquid limit، water content, and void ratio. The coefficient of consolidation of soft soil decreases with the increase of compression pressure. These parameters are basic for calculating the settlement of underground structures in Ho Chi Minh City.

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.

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