The Influence of Concentration of Pore Water Solution on the Swelling Characteristics of Expansive Soils

2012 ◽  
Vol 238 ◽  
pp. 427-430 ◽  
Author(s):  
Jing Chao Jia ◽  
Huan Li ◽  
Qing Tao Bi
Keyword(s):  
Pore Water ◽  
Expansive Soils ◽  
Water Solution ◽  
Swelling Pressure ◽  
Solution Concentration ◽  
The Other ◽  
Swelling Ratio ◽  
Swelling Properties ◽  
Swelling Characteristics ◽  
Volume Swelling

The influences of pore water solution concentration on the swelling properties of expansive soils were studied using the constant volume swelling pressure experiments and swelling ratio experiments under load. The results indicate that the swelling pressures decrease with the increase of solution concentration. Two specimens made by the same solutions concentration were immersed into solutions with two various concentrations to prepare specimen, one is smaller than the concentration of solution, and the other is same to that. The results show that the swelling pressures and the swelling strains of two specimens are very close. The analysis on the exist state of the pore water shows that the experimental results are agree with the osmotic pressure theory.

Influence of Existing State of Pore Aqueous Solution on the Swelling Pressure of Expansive Soils

2014 ◽  
Vol 919-921 ◽  
pp. 693-696
Author(s):  
Zhi Quan Huang
Keyword(s):  
Aqueous Solution ◽  
Osmotic Pressure ◽  
Pore Water ◽  
Expansive Soils ◽  
Swelling Pressure ◽  
Solution Concentration ◽  
Constant Volume ◽  
The Other ◽  
Experimental Result ◽  
Volume Swelling

The paper studies the influences of pore aqueous solution on the swelling pressure of expansive soils through the constant volume swelling pressure experimental experiment. The results indicate that the swelling pressures decrease with the increasing of solution concentration. In the experiment, two specimens made of the same solutions concentration are immersed into solutions with two different concentrations, one less than the solution concentration used to prepare specimen, and the other same to that. The results shows that the swelling pressures of two specimens gained from the experiment are very close. The analysis on the existing state of the pore water shows that the experimental result is agree with the osmotic pressure theory.

Studies on the determination of swelling properties of soils from suction measurements

2011 ◽  
Vol 48 (3) ◽  
pp. 375-387 ◽  
Author(s):  
B. Hanumantha Rao ◽  
K. Venkataramana ◽  
D. N. Singh
Keyword(s):  
Expansive Soils ◽  
Swelling Pressure ◽  
Soil Suction ◽  
Swelling Potential ◽  
Empirical Relationships ◽  
Swelling Properties ◽  
Swelling Characteristics ◽  
Stability Of Structures ◽  
Made In

Expansive soils exhibit significantly high volumetric deformations and hence, pose a serious threat to stability of structures and foundations. As such, determination of their swelling properties (viz., swelling potential and swelling pressure) becomes essential. Earlier researchers have developed various experimental techniques, and empirical relationships based on the results obtained from these investigations, for determining swelling characteristics of these soils. However, although these techniques help in direct estimation of the swelling properties of soils, the instrumentation is quite cumbersome and time consuming. This limitation can be overcome by measuring soil suction, which would also yield its swelling characteristics, though indirectly, but quite rapidly and easily. To demonstrate the utility and ease of application of this methodology, attempts were made in the present study to establish swelling properties of expansive soils from their suction measurements. Details of the methodology adopted are presented and results have been critically evaluated vis-à-vis those available in the literature.

scholarly journals Combined effect of mineralogical and chemical parameters on swelling behaviour of expansive soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bendadi Hanumantha Rao ◽  
Peddireddy Sreekanth Reddy ◽  
Bijayananda Mohanty ◽  
Krishna R. Reddy
Keyword(s):  
Expansive Soils ◽  
Research Work ◽  
Swelling Pressure ◽  
Combined Effect ◽  
Practical Significance ◽  
Chemical Compositions ◽  
Chemical Parameters ◽  
Swelling Behaviour ◽  
Mineral Contents ◽  
Swelling Properties

AbstractMicrolevel properties such as mineralogical and chemical compositions greatly control the macro behaviour of expansive soils. In this paper, the combined effect of mineral (i.e. montmorillonite, MMC) and chemical contents (i.e. Ca and Na in their total (T), leachable (L) and exchangeable form (CEC)) on swelling behaviour is investigated in a comprehensive way. Several 3-dimensional (3D) graphs correlating MMC and Ca/Na ratio, together, with swelling property (swelling potential, Sa, and swelling pressure, Sp) are developed. 3D plots, in general, portrayed a non-linear relationship of Sa and Sp with MMC and Ca/Na ratio, together. It is hypothesized that swelling initially is triggered by chemical parameters due to their quick and rapid ionization capability, but the overall swelling phenomenon is largely controlled by MMC. It is importantly found that expansive soils are dominant with divalent Ca++ ions up to MMC of 67% and beyond this percentage, monovalent Na+ ions are prevalent. From the interpretation of results, the maximum Sa of 18% and Sp of 93 kPa is measured at MMC of 43%, (Ca/Na)T of 10–14 and (Ca/Na)L of 2–7. It is concluded from study that total CEC + MMC for determining Sa and (Ca/Na)T + MMC for determining Sp are superior parameters to be considered. The findings of the study also excellently endorsed the results of Foster32, who stated that ionization of Na or Ca depends on the constituent mineral contents. The findings presented herein are unique, interesting and bear very practical significance, as no earlier research work reported such findings by accounting for chemical and mineralogical parameters impact, in tandem, on swelling properties.

An estimate of rebound potential of the Shaftesbury shales at a damsite in British Columbia

1992 ◽  
Vol 29 (3) ◽  
pp. 375-392 ◽  
Author(s):  
A. Hanna ◽  
T. E. Little
Keyword(s):  
British Columbia ◽  
Swelling Pressure ◽  
Stress Relief ◽  
Time Dependent ◽  
Swelling Properties ◽  
Deep Excavations ◽  
Hydroelectric Project ◽  
Stress Changes ◽  
Swelling Characteristics ◽  
Pressure Stress

The hydraulic structures of the proposed site C hydroelectric project in northeastern British Columbia would require deep excavations in Lower Cretaceous Shaftesbury shales. A significant stress relief would occur over most of the area to be occupied by the structures. Concerns about the magnitude and rate of time-dependent rebound and their impacts on project design, construction, and operation have been addressed. A review was made of several important case histories of other major projects constructed on Prairie shales. The properties of those shales were compared with the Shaftesbury shales. Long-term testing to establish the shale swelling characteristics was performed. Analyses were then made to evaluate potential elastic and time-dependent rebounds of the project area. A procedure for computing stress changes and time-dependent deformations due to the unloading effect of excavation followed by structural loading was developed. The procedure is useful in determining differential rebound that would occur in areas of steep topography or significant variations in the distribution of structural loads. Key words : rebound, shales, dam, swelling properties, swelling pressure, stress relief, deep excavations.

Measurement of swelling pressure: direct method versus indirect methods

2011 ◽  
Vol 48 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Kamil Kayabali ◽  
Saniye Demir
Keyword(s):  
Expansive Soils ◽  
Direct Method ◽  
Swelling Pressure ◽  
Expansive Clay ◽  
Swelling Properties ◽  
Indirect Methods ◽  
Natural Soils ◽  
Considerable Research ◽  
Free Swell ◽  
Swell Pressure

Light structures including highways and railroads built over potentially expansive clay soils may suffer damage from swelling. Considerable research has been done in an attempt to characterize swelling properties of expansive soils. Although direct measurement of swelling pressure is relatively straightforward, it has not drawn much interest. The present study attempts to measure swelling pressure directly. We call experimental techniques for swelling pressure other than this direct method the indirect methods. Some indirect methods require more than one soil sample and that all samples be identical. However, natural soils may not always provide identical samples. Therefore, reconstructed identical soil samples produced from natural soils were used in the present study. For comparison, the restricted swell, swell-consolidation, double oedometer, and zero swell tests were employed as indirect methods. While the restricted swell test slightly underestimated swell pressure, swell-consolidation and zero swell tests overestimated it. The double oedometer test did not provide swell pressures correlatable with those found using the direct method. Free swell data correlated reasonably well with swell pressure data from the direct method, so an empirical form was established from which swell pressure can be easily estimated.

scholarly journals An Experimental Study on the Effect of Micro-Metakaolin on the Strength and Swelling Characteristics of Expansive Soils

2022 ◽  
Author(s):  
Mohamed Sakr ◽  
Waseim Azzam ◽  
Mohamed Meguid ◽  
Hebatalla Ghoneim
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Soil Conditions ◽  
Arid Areas ◽  
Continuous Increase ◽  
Swell Index ◽  
The World ◽  
Swelling Characteristics ◽  
The Government

Abstract Expansive soils are found in many parts of the world, especially in arid areas and dry weather regions. Urbanization and development of new cities around the world resulted in construction in areas of challenging subsurface soil conditions. For example, in the Middle East, the Government of Egypt is building several new cities to accommodate the continuous increase in the country’s population. Most of these new cities are located in areas underlain by expansive soils. In this study, a series of laboratory tests were carried out to investigate the effect of introducing micro-metakaolin into the matrix of an expansive soil to improve the swelling potential as a new stabilizing material. Test results showed that micro-metakaolin can considerably decrease the free swell index of the soil by 37% and 54% at micro-metakaolin content of 15% and 25%, respectively. In addition, the shear strength of the soil was found to also increase as a result of the introduction of the micro-metakaolin material. Adding 25% micro-metakaolin content reduced the swelling pressure of the soil by about 33%. The results suggest that the proposed method is efficient in stabilizing and improving the properties of expansive soils found in arid areas. This is important to control excessive swelling and prevent possible damage to the supported structures.

Model for the simulation of swelling-pressure measurements on expansive soils

1998 ◽  
Vol 35 (1) ◽  
pp. 96-114 ◽  
Author(s):  
Fangsheng Shuai ◽  
D G Fredlund
Keyword(s):  
Pore Water ◽  
Volume Change ◽  
Unsaturated Soil ◽  
Pore Water Pressure ◽  
Expansive Soils ◽  
Water Pressure ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Oedometer Test ◽  
Free Swell

Numerous laboratory swelling tests have been reported for the measurement of swelling pressure and the amount of swell of an expansive soil. These test methods generally involve the use of a conventional one-dimensional oedometer apparatus. Few attempts, however, have been made to formulate a theoretical framework to simulate the testing procedures or to visualize the different stress paths followed when using the various methods. The simulation of the oedometer tests on expansive soils is required to fully understand the prediction of heave. The correct measurement of swelling pressure is required for an accurate prediction of heave. It is further anticipated that some information on unsaturated soils property functions may be approximated from the back-analysis of the data. A theoretical model is proposed to describe the pore-water pressures with time and depth in a specimen as well as the volume changes during various oedometer swell tests. The model is formulated based on equilibrium considerations, constitutive equations for an unsaturated soil, and the continuity requirement for the pore fluid phases. The transient water flow process is coupled with the soil volume change process. The model can be used to describe the volume-change behaviour, pore-water pressure, and vertical total stress development in an unsaturated soil during an oedometer test performed by any one of several test procedures. The model has been put into a finite element formulation using the Galerkin technique. All the parameters required to run the model can be obtained by performing independent, common laboratory tests. The proposed model was used to simulate the results from free-swell, constant-volume, constant water content, and loaded-swell oedometer tests. Computed values of volume change, vertical total stress, and pore-water pressure are in good agreement with measured values.Key words: unsaturated soil, expansive soil, swelling pressure, theoretical simulation, constant-volume oedometer test, free-swell oedometer test, loaded-swell oedometer test.

scholarly journals Swelling Characteristics of Clay Minerals According to the Ionic Strength in Pore Water

2021 ◽  
Vol 21 (6) ◽  
pp. 201-207
Author(s):  
Seok Gu Gang ◽  
Jongwon Jung
Keyword(s):  
Ionic Strength ◽  
Clay Minerals ◽  
Pore Water ◽  
Distilled Water ◽  
Swelling Ratio ◽  
Swelling Characteristics

An experiment to evaluate the swelling characteristics during saturation of representative clay minerals, kaolinite, illite, montmorillonite, and bentonite, according to the ionic strength of the pore water, was conducted. The results showed that in distilled water (DW), the average swelling ratios of kaolinite, illite, and bentonite were 10.95%, 12.51%, and 26.60%, respectively. However, montmorillonite exhibited a relatively large swelling ratio of approximately 152.6%. In 1 M brine, kaolinite, illite, and bentonite exhibited swelling ratios of 12.42%, 16.23%, and 21.91%, respectively, while that of montmorillonite was relatively small (0.83%). In the case of the ground containing montmorillonite, a high swelling ratio is expected with an increase in saturation and conductivity.

scholarly journals The prediction of total heave of a slab-on-grade floor on Regina clay

1983 ◽  
Vol 20 (1) ◽  
pp. 69-81 ◽  
Author(s):  
R. T. Yoshida ◽  
D. G. Fredlund ◽  
J. J. Hamilton
Keyword(s):  
General Theory ◽  
Pore Water ◽  
Unsaturated Soils ◽  
Pore Water Pressure ◽  
Expansive Soils ◽  
Water Pressure ◽  
Swelling Pressure ◽  
Practical Method ◽  
Industrial Building ◽  
Floor Slab

Several analytical methods for the prediction of total heave of desiccated, expansive soils have been proposed for various geographic regions. The proposed method herein is based on a general theory for unsaturated soil. The in situ stress conditions, as assessed from the corrected swelling pressure and the required soil moduli, are deduced from the constant volume oedometer test.Verification of the proposed method was accomplished using data accumulated from the monitoring of movements of a floor slab in a light industrial building in north-central Regina, Saskatchewan. A leak in a water line buried under the floor slab resulted in a maximum heave of about 106 mm. Of the three final pore-water pressure distributions assumed, the one where pressure is constant with depth and equal to atmospheric pressure appears to be representative of the field conditions corresponding to the maximum measured heave. The measured heave represents 89% of the predicted heave for the zero pore-water pressure distribution. It is concluded that the proposed method of analysis, based upon a general theory for unsaturated soils, provides a practical method to accurately assess total heave.

scholarly journals Study on the Swelling Behavior of Clayey Soil Blended with Geocell and Jute Fibre

2021 ◽  
Vol 7 (8) ◽  
pp. 1327-1340
Author(s):  
Sanjeev Kumar ◽  
Anil Kumar Sahu ◽  
Sanjeev Naval
Keyword(s):  
Construction Projects ◽  
Clayey Soil ◽  
Expansive Soils ◽  
Fibre Length ◽  
Swelling Pressure ◽  
Swelling Potential ◽  
Swelling Behaviour ◽  
Swelling Properties ◽  
Maximum Decrease ◽  
Mechanically Stabilized

Expansive soils like clays undergo swelling that can both be detrimental and acceptable in different applications. In the Northern part of India, especially Delhi region, natural soils containing clays & clayey sands support most of the buildings. Mechanically stabilized clays mixed with sand are used for local earthwork construction such as roads and landfills. Exact understanding of the swelling behaviour of such soils is a pre-requisite before the start of any construction projects. In this paper the swelling behaviour of clayey soil reinforced with geocell & Jute fibres has been presented. The laboratory investigations include one dimensional swelling tests using California Bearing Ratio (CBR) mould to study the swelling properties for different mix proportions. The maximum decrease in swelling potential of Geocell reinforced specimens was observed at fibre content of 0.80 percent and 40mm fibre length, beyond which increase in the swelling potential and swelling pressure has been observed. With this optimal reinforcement, a reduction of 71.24 percent in swelling and 41.10 percent in swelling pressure has been observed as compared to unreinforced soils. The study provides a solution towards the treatment of expansive soils before starting any construction activity over such soils and a step towards mitigating disasters related to infrastructure facilities grounded on expansive soils. Doi: 10.28991/cej-2021-03091728 Full Text: PDF

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