Strength of field compacted clays

1983 ◽  
Vol 20 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Y. Liang ◽  
C. W. Lovell
Keyword(s):  
Water Content ◽  
Effective Stress ◽  
Void Ratio ◽  
Volumetric Strain ◽  
Test Series ◽  
Dry Density ◽  
Regression Equations ◽  
Strength Parameters ◽  
Long Term Conditions ◽  
Initial Void Ratio

The reported research established the relationships among the compaction variables (dry density, water content, roller type, and number of passes) and the shearing behavior of a residual clay (St. Croix) from sandstone and shale. Compacted material was tube sampled from test pads, and subjected to two test series: unconsolidated-undrained (UU), and saturated consolidated-undrained [Formula: see text] triaxials. Both test series were run at various confining pressures to approximate the end of construction and long-term conditions for several embankment depths.The UU tests showed an increase in strength with an increase in density or a decrease in water content. For the as-compacted samples, significant volume changes occurred during shear. The volumetric strain at failure decreased with increasing prestress effected by the roller.In the [Formula: see text]testing program, sample behavior after saturation under confinement was interpreted in terms of initial compacted conditions (and confinement). The effective stress strength parameters were functions of the compacted water content and void ratio. For a given initial void ratio, as the compaction water content increased, c′ increased and [Formula: see text] decreased. The volumetric strain upon saturation varied with the compacted water content, dry density, compactive energy, and the level of confinement. Skempton's A factor at undrained shear failure was dependent upon the initial void ratio and the degree to which the sample had been prestressed by the roller.Statistically valid regression equations for these dependent variables, viz., as-compacted strength, percent volume change due to saturation and consolidation, Skempton's A parameter at failure, and the effective stress strength parameters, were developed for field compacted St. Croix clay. Uses for such equations are given.

Assessing Relations Between Electrical and Geotechnical Properties of Sand-Clay Mixtures Using Jonscher Fractal Power Law Model

2019 ◽  
Vol 24 (1) ◽  
pp. 77-85
Author(s):  
Fred Kofi Boadu ◽  
Samuel Ampadu
Keyword(s):  
Water Content ◽  
Effective Stress ◽  
Power Law ◽  
Void Ratio ◽  
Geotechnical Properties ◽  
Dry Density ◽  
Power Law Model ◽  
Stress Levels ◽  
Intergranular Void Ratio ◽  
Intergranular Void

The geotechnical properties of unconsolidated geo-materials such as soils are influenced by modifications of their micro-structure, texture, mineralogy, water content and imposed effective stress levels. Fundamental relations between the characteristic electrical parameters describing the electrical responses soils based on a fractal power law model with scaling properties, and parameters influencing their geotechnical behavior are investigated. Low frequency electrical conductivity laboratory measurements were performed on sand and clay mixtures subjected to varying effective stress levels with concurrent measurements of their geotechnical properties. The conductivity spectra of the mixtures were described using a Jonscher fractal power law model characterized with three characteristic parameters, the dc conductivity ( σ dc ), the characteristic frequency ( f c ) and an exponent ( n). Changes in effective stress, water content, clay content, and other engineering properties of the mixture such as dry density, porosity, pore size and intergranular void ratio are discussed with respect to changes in the electrical parameters. The dc conductivity and characteristic frequency decrease with an increase in effective stress levels. The exponent, however, has the opposite behavior and increases with an increase in effective stress. As the water content increases, σ dc and f c increase while n decreases for all mixtures. With increasing stress levels, the average pore size of the mixtures decreases which results in a decrease in σ dc and f c but an increase in the values of the exponent. An increase in dry density of the mixtures leads to a decrease in σ dc and f c whilst n increases. Both σ dc and f c increase with increase in the intergranular void ratio of the mixture whilst the exponent values decrease with an increase in the intergranular void ratio. This study serves as a contribution to our quest in utilizing electrical geophysical methods, to assess and monitor non-invasively, the geotechnical properties of the subsurface in a less expensive and faster manner.

scholarly journals A method of calculating the bearing capacity of sand pile composite foundations in a mucky soil layer considering consolidation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yongtao Zhang ◽  
Yuqing Liu ◽  
Huiwu Luo ◽  
Peishuai Chen ◽  
Dejie Li ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Water Content ◽  
Effective Stress ◽  
Void Ratio ◽  
Soil Layer ◽  
Composite Foundation ◽  
Engineering Practice ◽  
Application Process ◽  
Sand Pile ◽  
Cavity Expansion Theory

AbstractIn engineering practice, the measured bearing capacity of a sand pile composite foundation in a mucky soil layer is much larger than the design value. Based on the sand pile construction and the load application process, a method of calculating the bearing capacity of the foundation based on the effective stress was proposed. Cavity diameter expansion in sand pile construction was simplified into a planar problem, and the cavity expansion theory was used to establish the expression of the rate of displacement and the horizontal stress increase. Based on the e–p curve and the calculation of the degree of consolidation, the relationships between the horizontal and vertical effective stress and the void ratio were obtained. According to the close relationship between the bearing capacity of the foundation in a mucky soil layer and the water content, an expression describing the relationships between the bearing capacity of the foundation, effective stress, void ratio, and water content was established. For the temporary engineering foundation treatment project, which needs a high bearing capacity but allows large foundation deformation, the design of sand pile composite foundations uses these relationships to take the consolidation effect of mucky soil into consideration, thereby reducing the replacement rate and lowering the construction cost.

Experimental study on swelling characteristics of compacted bentonite

1994 ◽  
Vol 31 (4) ◽  
pp. 478-490 ◽  
Author(s):  
Hideo Komine ◽  
Nobuhide Ogata
Keyword(s):  
Water Content ◽  
Nuclear Waste ◽  
Volumetric Strain ◽  
Swelling Pressure ◽  
Dry Density ◽  
Initial Water Content ◽  
Initial Water ◽  
Compacted Bentonite ◽  
Swelling Characteristics ◽  
High Level

Compacted bentonites are attracting greater attention as back-filling (buffer) materials for repositories of high-level nuclear waste. However, since there are few studies about the swelling characteristics of compacted bentonites, it is first necessary to clarify the fundamental swelling characteristics in detail. For this purpose, various laboratory tests on the swelling deformation and swelling pressure of compacted bentonites were performed and the results analyzed. The following conclusions were drawn from the study. (i) The curve of swelling deformation versus time is strongly dependent on the initial dry density, vertical pressure, and initial water content. The maximum swelling deformation, however, is almost independent of initial water content, and the maximum swelling deformation increases in proportion to the initial dry density, (ii) The maximum swelling pressure increases exponentially with increasing initial dry density, whereas the maximum swelling pressure is almost independent of initial water content. (iii) The swelling mechanism of compacted bentonite was considered on the basis of the swelling behavior of swelling clay particles such as montmorillonite. Furthermore, a model of the swelling characteristics and a new parameter (swelling volumetric strain of montmorillonite), which were able to evaluate the swelling characteristics of compacted bentonite, were proposed. Key words : bentonite, laboratory test, nuclear waste disposal, swelling deformation, swelling pressure.

Isotropic yielding of unsaturated cemented silty sand

2013 ◽  
Vol 50 (8) ◽  
pp. 807-819 ◽  
Author(s):  
M. Arroyo ◽  
M.F. Amaral ◽  
E. Romero ◽  
A. Viana da Fonseca
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Void Ratio ◽  
Dry Weight ◽  
Silty Sand ◽  
Initial Void Ratio ◽  
Naturally Occurring ◽  
Experimental Campaign ◽  
Hardening Mechanisms ◽  
Designed Materials

Unsaturated cemented soils are frequent both as designed materials and as naturally occurring layers. Both desiccation and cementation act separately as hardening mechanisms, but it is not clear how exactly their effects combine. Do they enhance one another? Are they mutually reinforcing? This study presents results from an experimental campaign aimed at answering these questions. Five different mixtures of soil (a granite saprolite) and cement (with cement contents in the range 0% to 7% on a dry weight basis) are tested in isotropic compression at four different water content levels. Initial void ratio is also controlled, using two initial compaction densities. Loading is performed at constant water content and suction is inferred from a set of water retention curves obtained from parallel psychrometric and pore-size distribution measurements. The range of yield stresses explored in this study covers almost two orders of magnitude and extends up to 7 MPa at suction values of up to 14 MPa. Both desiccation and cementation increase yield stress, but their effects are less marked when both act together, and therefore they are not mutually reinforcing.

scholarly journals Definition and experimental determination of a soil-water retention surface

2010 ◽  
Vol 47 (6) ◽  
pp. 609-622 ◽  
Author(s):  
S. Salager ◽  
M. S. El Youssoufi ◽  
C. Saix
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Void Ratio ◽  
Silty Sand ◽  
Soil Water Retention ◽  
Initial Void Ratio ◽  
Hydromechanical Behaviour ◽  
Determination Methods

This paper deals with the definition and determination methods of the soil-water retention surface (SWRS), which is the tool used to present the hydromechanical behaviour of soils to highlight both the effect of suction on the change in water and total volumes and the effect of deformation with respect to the water retention capability. An experimental method is introduced to determine the SWRS and applied to a clayey silty sand. The determination of this surface is based on the measurement of void ratio, suction, and water content along the main drying paths. These paths are established for five different initial states. The experimental results allow us to define the parametric equations of the main drying paths, expressing both water content and void ratio as functions of suction and initial void ratio. A model of the SWRS for clayey silty sand is established in the space (void ratio – suction – water content). This surface covers all possible states of the soil inside the investigated range for the three variables. Finally, the SWRS is used to study the relations between water content and suction at a constant void ratio and between void ratio and suction at a constant water content.

Experimental Study on the Shear Strength Characteristics of Municipal Solid Waste

2011 ◽  
Vol 219-220 ◽  
pp. 660-664 ◽  
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu
Keyword(s):  
Shear Strength ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Effective Stress ◽  
Large Scale ◽  
Void Ratio ◽  
Influence Factor ◽  
Axial Strain ◽  
Strength Characteristics ◽  
Initial Void Ratio

Basing on the traditional tri-axial test instrument with large scale specimen, the shear strength characteristics of municipal solid waste has been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. Two different proportions of these three parts, which are 50%, 15%, 35% and 65%, 10%, 25% is selected. A series of laboratory tests have been performed for different proportion of ingredients, different initial void ratios and different confining pressures. Testing results show that the initial void ratio and the proportion of ingredients are the main influence factor for the shear strength of the municipal solid waste. Besides, the principle effective stress increases with the axial strain and the confining pressure in a hardening increasing trend, and the principle effective stress decreases with the increase of the initial void ratio of the municipal solid waste.

scholarly journals Significance of Stone Waste in Strength Improvement of Soil

2020 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
Amit Kumar ◽  
Kiran Devi ◽  
Maninder Singh ◽  
Dharmender Kumar Soni
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Fine Particles ◽  
Industrial Wastes ◽  
Dry Density ◽  
Regression Equations ◽  
Human Beings ◽  
Maximum Dry Density ◽  
Optimum Water Content ◽  
Optimum Water

The evolution of industries is essential for the economic growth of any country; however, this growth often comes with exploitation of natural resources and generation of wastes. The safe disposal and utilisation of industrial wastes has become essential for sustainable development. A possible approach would be to utilize these wastes in construction industries. The stone industry is one such flawed industries that generates waste in dust or slurry form; this leads harmful impacts on human beings, animals, and surrounding areas which, in turn, can lead to soil infertility. In the present study, stone waste was examined for its influence on maximum dry density (MDD), optimum water content (OMC) and unconfined compressive strength (UCS) of soil experimentally. Stone waste was used at 0%, 4%, 8%, 12%, 16% and 20% by weight of soil and UCS tests were conducted at maturing periods of 7, 14 and 21 days. Test results reported that the incorporation of stone waste improved the compressive strength value significantly. Maximum dry density was enhanced; however, optimum water content was reduced with the use of stone waste in soil due to its fine particles. Linear regression equations were also derived for various properties.

scholarly journals A Method of Calculating the Bearing Capacity of Sand Pile Composite Foundations in a Mucky Soil Layer Considering Consolidation

2021 ◽  
Author(s):  
Peishuai Chen ◽  
Huiwu Luo ◽  
Dejie Li ◽  
Enlong Liu ◽  
Benliang Yang
Keyword(s):  
Bearing Capacity ◽  
Water Content ◽  
Effective Stress ◽  
Void Ratio ◽  
Soil Layer ◽  
Composite Foundation ◽  
Engineering Practice ◽  
Application Process ◽  
Sand Pile ◽  
Cavity Expansion Theory

Abstract In engineering practice, the measured bearing capacity of a sand pile composite foundation in a mucky soil layer is much larger than the design value. Based on the sand pile construction and the load application process, a method of calculating the bearing capacity of the foundation based on the effective stress was proposed. Cavity diameter expansion in sand pile construction was simplified into a planar problem, and the cavity expansion theory was used to establish the expression of the rate of displacement and the horizontal stress increase. Based on the e–p curve and the calculation of the degree of consolidation, the relationships between the horizontal and vertical effective stress and the void ratio were obtained. According to the close relationship between the bearing capacity of the foundation in a mucky soil layer and the water content, an expression describing the relationships between the bearing capacity of the foundation, effective stress, void ratio, and water content was established. For the temporary engineering foundation treatment project, which needs a high bearing capacity but allows large foundation deformation, the design of sand pile composite foundations uses these relationships to take the consolidation effect of mucky soil into consideration, thereby reducing the replacement rate and lowering the construction cost.

Study on the Strength Characteristics of Municipal Solid Waste

2011 ◽  
Vol 204-210 ◽  
pp. 1835-1838
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Effective Stress ◽  
Large Scale ◽  
Void Ratio ◽  
Axial Strain ◽  
Confining Pressure ◽  
Strength Characteristics ◽  
Initial Void Ratio ◽  
Confining Pressures

Basing on the traditional tri-axial test on large-scale samples, the strength characteristics of municipal solid waste have been studied. The municipal solid waste is divided into three parts: incompressible solid waste material, reinforced material that is difficult to be biodegraded and the material that is easy to be biodegraded. The proportions of these three parts are 35%, 15% and 50%, respectively. Laboratory test has been performed for different initial void ratios, different proportion of ingredients and different confining pressures. The testing results show that the initial void ratio is the main factor that influences the strength of the municipal solid waste. Besides, the principle effective stress increases with the axial strain in a hardening increasing trend, even though the total axial strain has reached 40%. The principle effective stress also increases with the confining pressure that applied on the testing sample. Furthermore, the principle effective stress decreases with the increasing of the initial void ratio.

Study on the Shear Strength Parameters for Municipal Solid Waste with Higher Content of Organic Matter

2011 ◽  
Vol 295-297 ◽  
pp. 454-459 ◽  
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Test Specimen ◽  
Void Ratio ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Initial Void Ratio

Basing on the new developed direct shear testing instrument and the tri-axial test instrument with large scale specimen, the shear strength parameters of municipal solid waste has been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. The proportions of these three parts are selected as 80%, 5% and 15%, respectively. A series of laboratory tests have been performed for different initial void ratios, different vertical pressures and different confining pressures applied on the test specimen. Testing results show that the initial void ratio is the main influence factor for the shear strength parameters of the municipal solid waste, the relationship between the shear stress and the shear strain is a strain hardening curve, the shear stress increases gradually with the shear strain. Besides, the principle effective stress increases with the axial strain and the confining pressure in a hardening increasing trend, and the principle effective stress decreases with the increase of the initial void ratio of the municipal solid waste. The shear strength shows a linear relationship to the vertical pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the testing results of the direct shear test and the tri-axial test, the shear strength parameters are obtained. The cohesion varies from 4.7 to 12.2kPa, and the internal friction angle varies from 14.5 to 28.2 degree.

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