Engineering Behavior Of Soils Research Articles

Effect of Particle Shape on The Behavior of Polymer-Improved Sandy Soil Used in Pavements Due to Freeze-Thaw Cycles

Freeze-thaw cycles have a significant negative effect on the engineering behaviour of soil in cold regions. In this study, the compressive strength of stabilized, poorly graded sandy soil used in road pavement that was subjected to different freeze-thaw cycles was studied. Samples with three different particle shapes were stabilized with a binder developed by mixing polyvinyl acetate (PVAc) and ethylene glycol monobutyl ether (EGBE). The PVAc/EGBE weight ratio was 2:1, and PVAc was added at 1%, 2%, and 3% of the dry weight of the soil, with the effect of up to ten freeze-thaw cycles evaluated. Results showed that the addition of binder decreased optimum moisture content and increased compressive strength. An increase in particle roundness results in a decrease in the magnitude of compressive strength but increases the soil composite ductility. Changing particle shape from angular to rounded resulted in a more significant decrease in compressive strength than changing from rounded to well-rounded. The decrease in compressive strength is most significant between the first and fourth freezing-thawing cycles and marginal between the fourth and tenth. The negative effect of increasing the roundness of particles is compensated by increasing binder percentages.

Interrelationship among weathering degree, pore distribution and water retention in an unsaturated gneissic residual soil

It is widely recognised that the engineering behaviour of soils is a function of its structure. In residual soils, which are those derived from the in situ weathering of the mother rock and have not been transported from its formation site, the structure varies with the weathering degree of the material. It is also known that residual soils are usually unsaturated in nature. This study presents and discusses results of mercury intrusion porosimetry tests and soil-water retention tests performed in three sets of samples of a phacoidal gneiss residual soil, each one weathered to a different degree as preliminary defined through field observations and confirmed through extensive laboratory characterization tests and microtomography images. Based on a simplified definition of porosity ranges and through the introduction of a new porosity index, it is shown that the weathering degree affects, in differing ways, pores distribution and soil-water retention characteristics of the double-structure type of tested soils.

Experimental study of the effect of alkali contamination on geo-mechanical properties of the soil

As a civil engineer, we all are quite aware that the soils expansive in nature are not at all suitable as a material for foundation engineering purposes. Due to this very nature, geotechnical failures in expansive soil have been observed at various sites. Seasonal variations are responsible for swelling and shrinking that causes large volume changes in the expansive soil. Similar effects are also shown by the interaction of non-expansive soil with industrial sewage or effluent. It is a fact that engineering behavior of soil can be changed with the interaction of alkali. Alkali base solutions are discharged into the soil mass from differs industries, for example, paint and dyeing, paper manufacturing ventures, cotton factories and aluminum factories, etc. In this paper, an attempt has been made to investigate the effect of alkali interaction on engineering behavior of soil. For this, the samples of normal soil and contaminated soil were collected from Hindalco Industries Ltd., Renukoot (U.P.). The contamination was due to caustic liquor. The mechanical properties of normal soil and contaminated soil samples were investigated in laboratory by performing various geo-mechanical tests like specific gravity, grain size distribution, Atterberg’s limit, compaction characteristic, permeability, free swelling index, swelling pressure, shear strength parameter and consolidation characteristic.

State-of-the-art review on efficacy of xanthan gum and guar gum inclusion on the engineering behavior of soils

Soil amelioration is a challenging task in bulk civil engineering applications such as embankment slopes, landfill liner, pavement subgrade, retaining wall back fill. The conventional chemical stabilization techniques (i.e., cement, calcium hydroxide, sodium chloride, calcium chloride, etc.) inherently suffer from associated carbon emissions during their production stages. With the advent of biopolymers derived from natural sources having low embodied energy levels, they can replace conventional stabilizers. The current review article highlights the significant properties of two such biopolymers, i.e., xanthan gum (XG) and guar gum (GG), and their innate potential in stabilizing different soil types including mine tailings. The issues arising with wet and dry mixing of these biopolymers and suggested measures have been critically addressed. The degradation characteristics of biopolymers, which limit their use for bulk civil engineering applications, have been critically discussed, and the potential solutions to overcome durability issues are suggested. Future applications of these biopolymers in geoenvironmental engineering relying on the metal encapsulation properties are discussed in detail. It is believed that the selected biopolymers in this review are renewable, sustainable and remarkable materials with low embodied energy levels and low carbon footprint values compared to existing conventional stabilizers.

Absorption limit of kaolinitic and montmorillonitic soils

ABSTRACT Engineering behaviour of soils depends on the water present in it, which in turn depends on its capacity to absorb water. This property of soils may specifically be useful in predicting the performance of highways pavements. A simple method to predict water absorption capacity of soils through any of their index properties considering the factors influencing it would be beneficial, not only for preliminary assessment of its influence on soil behaviour and performance of structure, but also aid to take preventive measures to alter this property of soil before use. From the results of this study, it was found that both types of clay minerals as well as drying have an influence on their water absorption limit. It also has a good relation with their respective liquid limits, being lesser for kaolinitic soils than the montmorillonitic soils; and it is more for air-dried samples than the oven-dried samples, irrespective of the type of clay mineral.

Influence of Plastic Waste Strips on Engineering Behaviour of Soils

Influence of Plastic Waste Strips on Engineering Behaviour of Soils

EFFECT OF SOAK PIT ON THE CONSOLIDATION BEHAVIOR OF THREE ZONE SOIL IN KARNATAKA

The present research work discuss about the consolidation behavior of three zone soil which are collected neat soak pit regions from kanakapura, Hoskote and Dodaballapur,Karnataka,India at a depth of 0.5 meters from natural ground level and at a radial distance of 2.5 meters away from the pit area by using auger boring. In the above regions human excreta with sewage is directly discharged into these pits. From the pit contaminants will travel a maximum distance of 10 meters and also may travel vertically downwards and pollute the underground water and it also affects the engineering behavior of soil. So we are interested to know the consolidation characteristics of these regions soil. An attempt also made to have a consolidation comparative study of three above specified zone soil due to intrusion of contaminants. From the one dimensional fixed ring Consolidation test it is observed that Hoskote soil requires higher Pre-Consolidation pressure and hence its rate of permeability is less compared to other soils on the other hand Dodballapur soil requires lower Pre-Consolidation pressure for Consolidation of soil. This reflects the softening of soil due to contaminants intrusion near soak pit area.

Assessment of Stress History of Jiangsu Clay Deposits from Seismic Piezocone Penetration Testing (SCPTU) Data

The stress history as indicated by the profile of overconsolidation ratio (OCR) or preconsolidation pressure of a soil deposit is one of the dominant factors that influence the engineering behavior of soils. A commonly used method to obtain the parameter is a laboratory oedometer test, which is of low accuracy and time consuming because of inevitable sample disturbance. The purpose of this article is to assess the capability of existing interpretation methods and develop new methods to reasonably predict the OCR of clayey soils utilizing the seismic piezocone penetration test (SCPTU) data. Seven sites in Jiangsu province of China were used for this study. At each site, in situ SCPTU tests were performed and soundings of cone tip resistance (q c ), sleeve friction (fs), pore pressures (u 2), and shear wave velocity (Vs) were recorded. High-quality Shelby tube samples were collected close to the SCPTU tests and used to conduct laboratory oedometer consolidation tests to evaluate the reference OCR values. The predicted OCR values from different methods were compared with the laboratory OCR values. The results showed that all the investigated SCPTU methods overpredict the laboratory-calculated OCR. The collected data were further used to develop two new SCPTU methods that can estimate the OCR reasonably.

Influence of Seawater on the Suction and Swelling Behavior of Clayey Soils

The present study examines the suction characteristics and swelling behavior of clayey soils when exposed to natural seawater with respect to distilled water. The effects of saline waters on the engineering behavior of soils need to be determined since the salinity of the pore fluid of soils near coastal areas increases continuously. Six clayey soil samples with different mineralogy and characteristics were gathered and tested to determine the suction and swelling characteristics in the presence of natural seawater and distilled water. The results show that the total suction values of the samples are higher in the presence of seawater than in distilled water. The samples with high swelling potential have lower matric suction values than nonswelling soils. Moreover, in contrast to swelling-type soils, the matric suction values of the nonswelling soils remain similar in the presence both distilled water and seawater. The modified free swell index (MFSI) of the samples is well correlated with the liquid limit (LL), plasticity index (PI), and cation exchange capacity (CEC) in distilled water. However, coefficients of determination decreased in the presence of seawater. Also, there is no significant correlation existing between total and matric suction values and the MFSI values of the samples.

Effect of Coir Waste on the Geotechnical Characteristics of Soil

Abstract Kerala (the southernmost state in India), which is named after a coconut tree, is the first place that produced coir. The process of coir extraction produces coir waste, the disposal of which is becoming a major problem recently. Coir waste includes dusty matter called coir pith, along with some baby fibers. Studies have not yet been conducted on the influence of these coir wastes regarding the engineering behavior of soil. Two types of soils viz. lateritic soil and soft clay have been considered using different percentage of coir waste ranging from 0.5 % to 3 % by weight of soil. The main objective of the present investigation is to assess the usefulness of coir waste as a soil admixture and is focused on its influence on the engineering properties of soil. The present study covers the characterization of soils and coir pith, compaction behavior, CA bearing ratio, swelling and compressibility behavior. The results show that addition of coir waste modifies the geotechnical characteristics of both types of soils.

Chapter 8 Engineering behaviour of desert soils

Whilst a wide range of soils and rocks may be encountered in desert areas, hot desert soils are typically characterized by: Engineering works will generally lead to changes in stress or changes in moisture content in the ground, and this chapter outlines the soil mechanics frameworks that allow the response to these changes to be assessed. In arid environments, wetting of the soil from its natural dry state is a common result of construction activity and urban development. Ground movements caused by swelling or collapse of the soil may result. These movements can be relatively large and are often more significant than those resulting from a change in total stress. The arid conditions allow soluble salts to remain in the soil, and they are thus encountered at depths and at concentrations not normally found in wetter environments. If the equilibrium is altered by changes in the groundwater regime, ingress of water or in the amount of evaporation at the ground surface, then leaching or precipitation of salts may lead to volume changes or changes in strength and/or stiffness of the ground. Salts may also change from anhydrous to hydrated forms (or vice versa) with consequential volume changes and associated ground movements. All of these characteristics may be present in a given soil, which could, for example, be partially saturated and weakly cemented by soluble salts, and expand when wetted at low stress but collapse when wetted under higher stresses. The engineering behaviour of these soils can be understood in the context of partially saturated soil mechanics, with consideration given to factors specific to arid environments such as particular types of soil structure and the common occurrence of salts. However, although research in universities and companies …

Effect of Microfabric on Undrained Static and Cyclic Behavior of Kaolin Clay

Microfabric plays an important role in the engineering behavior of soils. Although many studies are available in the literature on the effect of microfabric on the static behavior of soils, the effect on the cyclic behavior is less understood. In the present study, samples with different microfabric were prepared in the laboratory by reconstituting commercially available kaolin clay with different pore fluids under a consolidation pressure of 100 kPa. Consolidated undrained triaxial tests were carried out on these samples under static and cyclic loading conditions. Dispersed samples were found to have monotonic stress-strain behavior with a peak deviatoric stress and higher peak undrained shear strength than the flocculated samples. However, the dispersed samples were found to offer less resistance to cyclic loading. When subjected to cyclic loading, dispersed samples failed within a few cycles under a cyclic stress ratio (defined as the ratio of cyclic deviatoric stress to the undrained shear strength) close to 0.6, whereas in flocculated samples, sudden failure was not observed even at a higher cyclic stress ratio of 0.9, although strains and pore pressures accumulated to higher values. Postcyclic monotonic tests conducted on samples that did not fail under cyclic loading showed an apparent overconsolidation effect caused by cyclic loading in a similar manner, as reported in the literature.

Predictions of the OCR from Piezocone Tests in Quaternary Clays

As indicated by the profile of overconsolidation ratio (OCR), the stress history of a soil deposit is one of the dominant factors that influence the engineering behavior of soils. A commonly used method to obtain the parameter is the laboratory oedometer test, which is of low accuracy and time consuming because of inevitable sample disturbance. These difficulties can be overcome by in situ pizeocone penetration test, which provides continuous measurement of cone resistance, sleeve friction, and pore water pressure induced during the penetration. Though many methods have been proposed to estimate the preconsolidation pressure and overconsolidation ratio of clay deposits, their validity still needs to be proved. In this study, existing empirical methods for interpreting stress history of clays through piezocone tests are briefly reviewed. It is shown that regional correlations are valid. Piezocone tests utilizing a Vertek-Hogentogler CPTU truck that have been completed at different sites in the Jiangsu province of China. Existing correlations are compared with these field test data. It is shown that the correlation based on normalized net tip resistance is pretty accurate for determining the overconsolidation ratio of Quaternary clay deposits.

Investigation of Engineering Behavior of Soil,Polypropylene Fibers and Fly Ash -Mixtures for Road Construction

Investigation of Engineering Behavior of Soil,Polypropylene Fibers and Fly Ash -Mixtures for Road Construction

In situ pore pressures: What is their significance and how can they be reliably measured?

The intergranular fluid pressure in a soil matrix (pore pressure) has fundamental influence on the engineering behaviour of soils. Often assumptions are made regarding pore pressures, however, in critical analyses direct measurement of pore pressures should be made. This paper discusses the pore pressure measurements made at the Ormen Lange field. Pore pressure measurements using piezometers indicate pore pressures in excess of hydrostatic at the back wall of the slide and the Stornese feature. Hydrostatic pressures have been identified on the North Flank and in the basin of the slide. Dissipation tests performed during the field investigation did not yield reliable in situ pressure estimates. The pore pressure measurements from the piezometers are consistent with the assumptions required in the theoretical slope stability analyses explaining the Storegga slide mechanism. As no standard commercially available technology for autonomous pore pressure monitoring exists, the paper describes also the technical solutions designed and implemented for pore pressure monitoring at the Ormen Lange field.

Effects of Temperature and Heat on Engineering Behavior of Soils

Effects of Temperature and Heat on Engineering Behavior of Soils

Effects of Temperature and Heat on Engineering Behavior of Soils

Effects of Temperature and Heat on Engineering Behavior of Soils