Soil Index Properties Research Articles

Consolidation test on peat soil of Humbang Hasundutan regency, North Sumatera Province

The purposes of this study were to determine the index properties of peat soil, to determine the classification of peat soils and to determine the consolidation coefficient (Cv ) and compression index value (Cc ) of peat soil in Nagasaribu Village, Lintong Nihuta sub-District, Humbang Hasundutan Regency, North Sumatera province. This research was conducted through a consolidation test with direct loading of 9.810 Newton and 19.613 Newton and gradually loading of 9.810; 19.613; 39.226; 78.453; and 156.96 Newton. The peat soil in Nagasaribu Village, Lintong Nihuta sub-District, Humbang Hasundutan Regency has a high water content (w), of 628.139%, specific gravity (Gs) of 1.301, moist unit weight (γ) of 10.125 KN/m3, dry unit weight (γd) of 1.390 KN/m3 and void ratio (e) of 8.157. Based on ASTM D4427-92 (2002), the sample of peat soil was classified as low ash peat because it had 0.780% ash content and 26.500% organic content. And according to the acidity level with a pH of 4,000, the sample was classified as highly acidic peat soil. The compression index (Cc ) of sample 1 was 3.044 and sample 2 was 3.574 and the consolidation coefficient (Cv ) of sample 1 was 2.155 cm2/sec. and sample 2 was 1.818 cm2/sec.

Influence of Rock Powder on the Geotechnical Behaviour of Expansive Soil

Expansive soils create challenges in civil engineering projects due to their tendency to significant volume changes with variation in moisture content. In this study, an experimental study was carried out to evaluate the influences of rock powder on the geotechnical properties of expansive soil. This paper presents the results of some index and engineering properties of expansive soil mixed with the rock powder, including Atterberg limits, compaction, free swelling, unconfined compressive strength (UCS), California bearing ratio (CBR), direct shear, and permeability at different percentages (0%, 8%, 16%, 24%, 32, and 40% by dry soil weight). The results reveal that the index properties, optimum moisture content, free swelling, cohesion, and coefficient of permeability decrease with the addition of rock powder up to 40%. Whereas, the maximum dry density, UCS, and CBR increase up to 24% of rock powder thereafter reversed. Furthermore, the internal friction angle increases by 95.32%, while the subbase thickness layer for a roadway could be reduced by 40% with the addition of 40% rock powder to the soil samples. Based on the test results, the optimum ratio of rock powder for the improvement of expansive soil is about 24%.

Effects of water saturation and distribution on small-strain stiffness

The purpose of this study is to investigate the role of the degree of saturation and water distribution patterns on small strain soil properties. First, we measure P- and S-wave velocities of fine sands mixed with varying degrees of water saturation Sw = 0, 5, 30, 60, and 100% during the vertical loading under zero-lateral strain conditions. Next, we use a simple geometry analysis combined together with soil index properties to provide the first-order approximation of capillary pressure. Then, we consider the effect of capillarity on soil skeleton stiffness to analyze the data in the context of Gassmann's framework. Finally, we investigate the effect of water distribution patterns on small strain soil properties. Results show that water distribution pattern is a critical factor to control the low perturbation soil properties. Furthermore, a specific surface appears to be a good indicator to predict the effective stress- and pore size-dependent capillary pressure in the determination of small strain geophysical properties.

Strength Enhancement Potential of Spent Calcium Carbide on Fine Grained Lateritic Soil

Effect of spent calcium carbide (SCC) on index and strength properties of lateritic soil at differ- ent compactive efforts was assessed in this study as potential means of improving the geotechnical properties of the subsoil as well as disposing of SCC as waste. SCC was admixed with the soil using 0 to 10 % by dry weight of soil at an incremental rate of 2%. The following tests were carried out on the samples: specific gravity, Atterberg limit, particle size distribution, compaction, and California bearing ratio (CBR). Compaction and California Bearing Ratio (CBR) tests were carried out using British Standard light (BSL), West African Standard (WAS), and British Standard heavy (BSH) on both the natural and stabilized soil samples. From the investigation, atterberg limits show a reduction in the plasticity index with increasing content of SCC. The maximum dry density of the soil decreased with increasing SCC content and increased with an increase in compactive energies (BSL<WAS<BSH), while and optimum moisture content (OMC) increased correspondingly. Also, soaked and unsoaked CBR values of the stabilized lateritic soil showed an increase in strength with higher compactive effort, and SCC content up to 4% SCC addition and after that decreased in value. Based on these results, spent calcium carbide improved the geotechnical properties of this lateritic soil, and 4% SCC is recommended for its stabilization as subgrade material for pavement construction, thereby serving as an effective method of disposing SCC towards promoting a green and sustainable environment.

Prediction of Compaction Parameters from Soil Index Properties Case Study: Dam Complex of Upper Atbara Project

Soil compaction involves concretion and a relative variation of physical and mechanical properties of soils. Determining laboratory compaction characteristics such as maximum dry density (MDD) and optimum moisture content (OMC) could be vital work to manage field compaction for all earth-works structures. There are 3 necessary Atterberg limits: plastic limit (PL), liquid limit (LL), and Plastic Index (PI). The most objective of this paper is to get the relationships between compaction parameters and their Atterberg limits of fine-grained soils and to create reliable correlations. For conducting this work, forty samples are collected from a borrowed space that is found at the bank upstream of Setit watercourse. The tests of soil samples were executed at the laboratory of Dam complex of the upper Atbara project. To perform this work, the Microsoft Office Excel software was exercised for the regression analysis of compaction parameters and Atterberg limits. Several trials were created to get the relationships between Atterberg limits (LL, PL, and PI) with the compaction parameters (OMC, and MDD). From the regression analysis, it's found that OMC and MDD have an excellent relationship with the LL other than the PL and PI. It had been observed that the (OMC) has an excellent correlation with (MDD) other than the remaining parameters. From this work, it's going to be suggested to use the soil compaction properties and Liquid Limits' correlations attributable to their reliable results compared with the other correlations. The result of the paper may be helpful and applicable in numerous civil engineering sectors, particularly for preliminary investigations and prefeasibility studies of various civil engineering works.

Characterization and Classification of Geotechnical Index Properties of Shallow Soil Deposits at Oworoshoki Area, Kosofe Local Government, Lagos, Nigeria

The study of geotechnical index properties of soils in Oworoshoki, Kosofe, Lagos State was conducted to characterize and classify the index properties of soil samples. Disturbed and undisturbed soils were collected at different shallow depths (1m, 2m and 3m) from the study area and laboratory test was conducted. The laboratory test conducted includes natural moisture content, atterberg limits (liquid limit and plastic limit), particle size distribution, specific gravity, unit weight and hydrometer. The results of the test were gotten: natural moisture content as 23.5%, 24.5% and 25.3% , liquid limits (LL) 28.68%, 26.64% and 29.10%, Oworoshoki is non-plastic for the three depths i.e. plastic limit (PL) is 0, particle size distribution percentage passing through BS #200 (0.075mm) are 95.97 %, 97.97%, 98.10% and this shows that the soil sample contain much silt, the samples are non-plastic for all depths (1m, 2m and 3m), specific gravity as 2.61, 2.55 and 2.60, unit weight as 17.5 KN/m3, 18.1kn/m3 and 18.9KN/m3 and hydrometer percentage passing through BS #200 (0.075mm) as 95.97% at 1.0m depth, 97.97% at 2.0m depth and 98.10% at 3.0m depth. Hydrometer test was conducted because 95.97% passes sieve 0.075mm.This shows that the soil contain high amount of silt. Soils from depth 1.0m, 2.0m and 3.0m are non-plastic (NP) because the Plastic Index (PI=0) and the soil samples are classified as A – 3 according to American Association of State Highway and Transportation Officials (AASHTO) System.

Statistical Analysis on Shear Strength Parameter from Index Properties of Fine-grained Soils

Shear strength is the essential engineering property of soil required to analyze and design foundations, retaining walls, bridges, embankment, and related infrastructure. The laboratory equipment and field instruments are not sufficient in developing countries to obtain soil engineering properties, especially strength properties. Thus, Geotechnical engineers usually endeavor to develop statistical models that best fit a particular area and soil type, especially for analysis and design purposes. In this research, a Statistical Analysis on the Shear Strength parameter from the Index Properties of Fine-Grained Soils was studied. For predicting the undrained shear strength parameter, single linear regression (SLR) and multiple linear regressions (MLR) analyses were developed. To develop the intended statistical models for a study, SAS JMP Pro 13, SPSS v22, and Microsoft Excel-2013 software were introduced. The results of a study indicated that undrained shear strength(Cu) was significantly correlated with liquid limit(LL), plastic limit(PL), bulk density (ρbulk), dry density(ρdry), natural moisture content(NMC), and plasticity index(PI). While it was not significantly correlated with a specific gravity (Gs) and liquidity index (LI) of study area soil. Finally, a strong Model of Cu with a coefficient of determination (R2 = 0.806), good significance level, and less Std. error was obtained from multiple linear regression (MLR) analysis. The developed model can figure undrained shear strength parameter and wide application in the construction industry to minimize the cost, effort, and time for laboratory tests of shear strength parameter of a study area.

Fuzzy Knowledge Based System for Suitability of Soils in Airfield Applications

Proper design of roads and airfield pavements requires an in-depth soil properties evaluation to determine suitability of soil. Soft computing is used to model soil classification system's dynamic behaviour and its properties. Soft computing is based on methods of machine learning, fuzzy logic and artificial neural networks, expert systems, genetic algorithms. Fuzzy system is a strong method for mimicking human thought and solves question of confusion. This paper proposes a new decision-making approach for soil suitability in airfield applications without a need to perform any manual works like use of tables or chart. A fuzzy knowledge - based approach is built to rate soil suitability in qualitative terms for airfield application. The proposed model describes a new technique by defining fuzzy descriptors using triangular functions considering the index properties of soils as input parameters and fuzzy rules are generated using fuzzy operators to classify soil and rate its suitability for airfield applications. The data obtained from the results of the laboratory test are validated with the results of the fuzzy knowledge-based system indicating the applicability of the Fuzzy model created. The approach developed in this work is more skilled to other prevailing optimization models. Due to its system’s flexibility, it can be suitably customized and applied to laboratory test data available, thus delivering a wide range for any geotechnical engineer. Doi: 10.28991/cej-2021-03091643 Full Text: PDF

Unified Evaluation of Consolidation Parameters for Low to High Plastic Range of Cohesive Soils

Knowing the engineering properties of geomaterials is imperative to make the right decision while designing and executing any geotechnical project. For the economical and safe geotechnical design, quick characterization of the compressibility properties of the cohesive soil is often desirable; these properties are indeed tedious to determine through actual tests. Therefore, correlating the consolidation parameters of the soils with its index properties has a great significance in the geotechnical engineering field. Several attempts have been made in the past to develop correlations between the consolidation parameters and index properties of the cohesive soils, within certain limitations. However, there is still a need to develop such correlations based on the extensive database, composing of unified plasticity range of soils, i.e., low to high plasticity. In the current study, 148 undisturbed soil specimens were obtained from different areas of Pakistan. Out of which 120 samples were utilized to develop correlations, and 28 samples were used to check the validity of the developed correlations. In order to enhance the index properties database, 30 more bentonite mixed soil samples were prepared and tested accordingly. Correlations to envisage different consolidation parameters such as compression index, compression ratio and coefficient of volume compressibility were developed using 150 cohesive soil samples of low to high plasticity. In addition, the performance of these developed correlations was verified on a set of 40 soil samples and compared with the performance of different correlations available in the literature. The percentage deviation in the prediction of compressibility characteristics through developed correlations in the present study was found to be very less, which endorsed the excellent reliability of the developed correlations.

Relationship between dielectric constant of soils with clay content and dry unit weight

The monitoring of water movement and transfer into the ground is very important for assessing mechanisms such as settlements, ground contamination, road collapse or landslides, to name a few. Soil moisture can be indirectly measured with different techniques. In this paper, a three-phase mixed α model of the soil dielectric constant is considered and the parameters are calculated considering a large database (experimental and from literature). Then, the physical meaning and interpretation of those parameters are described from the viewpoints of the soil index properties (i.e. soil type, dry density ρdand clay content).

A Review on Correlations for Consolidation Characteristics of Various Soils

Settlement is the major problem that arises after the construction of a structure on a soil mass. Consolidation characteristics of soil such as coefficient of consolidation cv, compression index cc, recompression index cr, preconsolidation pressure σ′p play a major role in the settlement behavior of fine grained soil mass. cv represents the rate of consolidation of soil mass. cc and cr are essential in calculating settlement of normally and over consolidated clays respectively. σ′p is determined to find whether the clay is under, normally or over consolidated. These consolidation properties are obtained from graphical constructions after conducting several one dimensional consolidation-oedometer tests. Since this is time consuming, many correlations have been derived between consolidation properties and index properties of soil. Different researchers have used various soil parameters such as liquid limit (wL), plastic limit (wp), natural moisture content (wn), initial insitu void ratio (eo), dry unit weight (γd), plasticity index (Ip), void ratio at liquid limit (eL) etc., as correlative parameters for deriving the correlations. Hence, it is desirable to predict the value of cv, cc, cr and σ′p from the known correlations rather than conducting several tests, to ease the procedures.

Reinforcing of Sand With 3D Printed Fibres – Review of Properties, Fabrication of Fibres and Initial Testing Programme

Fibre reinforcement is an effective method of soil improvement that presents an alternative solution to other more common methods of ground reinforcement, such as mechanical stabilization by geosynthetics (geogrids, geotextiles, geocomposites, etc.). Research activities in this area are being carried out, but the main disadvantage of currently used fibres is their uniform cross-section and usually smooth surface given by available production methods. This study presents an alternative way of fabrication of synthetic fibres – utilization of fused deposition modelling (3D printing). With the rapid development in commercially available 3D printing techniques, it is now possible to refine the shape and dimensions of the 3D printed objects to a tenth of a millimetre. The review of the basic index and mechanical properties of fibre-reinforced soils is presented in the first part of the paper. The second part is devoted to the description of the production process of fibres including the suitability analysis of materials used for 3D printing. Finally, the initial testing programme of fibre-reinforced non-cohesive soil is presented. The preformed laboratory test confirmed that the inclusion of 3D printed fibres led to a significant increase in shear strength. Examination of samples after tests did not reveal breakage of fibres, thus the fibres pull-out was the governing failure mode.

Effect of cyclic heating on some engineering characteristics of some soils from Ilorin, Nigeria

This work investigates probable changes during repeated heating and cooling cycles on some index and engineering properties of some lateritic soils. Bulk soil samples were taken within Ilorin metropolis. These samples were oven dried for 24 h at 110 oC and cooled naturally to room temperature. This procedure was repeated four times. The effect of cyclic heating and cooling on various soil properties including Atterberg limits, particle size distribution, moisture—density relationship and California bearing ratio (CBR) were investigated. The results show that maximum dry density (MDD) reduced consistently with repeated heating and cooling while optimum moisture content (OMC) increased. CBR increased with repeated heating and cooling up to 23.5%. A percentage decrease in liquid limit up to 25% was recorded while plastic limit and plasticity index reduced in all samples. Increase in CBR is an indication of increase in strength with repeated heating while the decrease in MDD is an indication of reduced density on account of increase in OMC of the soil samples with repeated heating.

Effect of Functional Group of the Inorganic Additives on Index and Microstructural Properties of Expansive Soil

Expansive soils exhibit volume-change behaviour on exposure to moisture changes due to the presence of the montmorillonite mineral. The swell–shrink behaviour of these soils could lead to instability of the structures found on them, specifically the light-weight structures and pavements. Chemical stabilisation of expansive soils has always proven to be more successful in mitigation of swelling, compared to other methods of removal, replacement, and structural alterations. The present study focuses on the behaviour of a representative expansive soil treated with a conventional inorganic additive (lime) and less explored additives like calcium chloride and magnesium hydroxide, with a view to understand the effect of functional group of the inorganic additives in curtailing the swelling behaviour of the soil. The phenomenon of stabilisation is compared in terms of index and engineering properties based on the quantity of additives and curing period adopted. The macrostructural properties are evaluated through the changes in the plasticity characteristics, stress–strain behaviour, swell and permeability properties. The microstructural aspects of the treated soils are determined in terms of specific surface area, pore size measurements and minerology. Microlevel and macrostructural parameters are correlated to understand the soil-additive interaction and to quantify the extent of stabilisation and permanence of the additive induced changes. The lime and Mg(OH)2-treated samples effectively alleviate plasticity characteristics of the soil. However, strength of the lime-amended soil gets significantly improved, contributing to nearly 180% increase in strength compared to 100% and 45% increase for CaCl2- and Mg(OH)2-amended soils. Further, the additives also completely nullify the swelling phenomenon. The microstructure properties, SSA and pore size of the treated soils are concomitant with the macrolevel properties, such as permeability, swell and strength characteristics of treated soils, which further confirm the particle orientation of the soil on additive amendment. These analyses give a clear understanding of the orientation of the soil fabric, which dominates the overall behaviour of the soil-additive composites.

Enhancing Index and Strength Properties of Black Cotton Soil using Combination of Geopolymer and Flyash

A Combination of admixtures - fly ash and Geopolymer are used for stabilization of black cotton soil. Black cotton (BC) soils are mainly clayey soils having montmorillonite as their clay mineral. The moisture changes in BC soils will affect compressibility and strength characteristics, which are greatly enhanced with the addition of combination of Flyash (FA) and Geopolymer (GP). The evaluation study includes analysis of soil properties some of index properties like specific gravity, liquid limit, shrinkage limit and Uniaxial compression values. Different percentages of combination of admixtures (percentage by dry weight) are added to natural BC soil and further experiments are performed from these soil mix ratios (MR). The results show that the utilization of combination of admixtures decreases liquid limit by enormously and increases unconfined compressive strength i.e. the strength of the soil.

Estimating the overconsolidation ratio in uniform cohesive soil with cone penetrometer tests considering soil structure and index properties

A basic empirical approach to estimate the preconsolidation stress and overconsolidation ratio, OCR, in uniform cohesive soils using cone penetration and piezocone tests uses a correlation factor, kc, that is equal to the preconsolidation stress divided by the net tip stress referenced to the soil plasticity index. An adaptation of the “stress history and normalized soil engineering properties” (SHANSEP) format extends this basic approach by organizing the data into normally consolidated and overconsolidated components. The SHANSEP-based approach is improved in this paper by applying an empirical method to identify structured and unstructured soil behavior and to develop a separate empirical correlation for each type of soil structure. Overconsolidated structured soils are shown to exhibit kc values less than the normally consolidated kc and the m exponent in the SHANSEP relationship is greater than 1. In unstructured overconsolidated soils, the kc value is greater than the normally consolidated kc value and the SHANSEP m exponent is less than 1. The proposed method to identify structured vs. unstructured behavior is an important improvement in the approach and helps illustrate why some mCPTu values are less than 1 and others are greater than 1. Site characterization efforts are significantly improved when structured soil behavior is identified and included in the assessment of OCR.

WITHDRAWN: Phenomenal transmutations in quality of soil attributable to stubble burning a case study of Punjab, India

Abstract Burning paddy remains after harvesting by the farmers not only degrades the soil quality but also affects the physical and engineering properties of soil. The aim of this study is to quantify the phenomenal alterations in quality of soil attributable to stubble burnings by farmers in the district of Amritsar in Punjab state, India. A set of samples were collected from three locations randomly chosen within the study area and appropriate laboratory tests were carried out on eight soil property indicators. To quantify changes in the engineering properties of the soil, standard proctor test, direct shear test and unconfined compression tests were performed on the soil samples. In this study, some substantial changes were observed in liquid limit, plastic limit, optimum moisture content and specific gravity in the post stubble burning. Liquid limit, plastic limit and optimum moisture content of soil reduced in all the areas whereas, specific gravity decreased in some areas and remained virtually unchanged in one. The results also illustrate decline of direct shear test where cohesion of soil decreased by 5.68KN/m2 and angle of internal friction increased by 0.80° whereas, dry density was changed by + 0.95KN/m3. In unconfined compression test, compressive strength of soil was changed by + 2.5KN/m2 after stubble burning. From the observations it can be concluded that stubble burning not only puts adverse effect on the index properties of soil but also the engineering properties change considerably. We recommend geoscientists to think of the radical change in the index and engineering properties of soil related to the reduction of soil fertility.

ESTIMATING COMPACT PARAMETERS WITH SIMPLE AND MULTIPLE REGRESSION ANALYZES AND ANALYSIS OF THE MEANING WITH THE F TEST

Compaction is the compaction of the moist soil by laying it in layers, rolling it by applying vibration. Compaction is widely used both for the frequency control of road embankments and embankment dams and in other important engineering projects. Therefore, it is important to determine the compaction parameters correctly. The lack of sufficient laboratory equipment at the construction sites and the limited deadline of work increased the importance of correlation equations. If there are sufficient data and results are obtained within tolerable safety limits, it is considered appropriate to use statistics in estimation of compaction parameters. This situation provides a gain both in terms of economy and time. In the study, the compaction parameters were tried to be estimated by subjecting the soil index properties of Adıyaman Balkar, Çelik and Pınaryayla Ponds to simple and multiple regression analyzes. First, the data of the soils belonging to the ponds were used, then, as a result of the sieve analysis, the index properties of fine-grained soils containing only clay and silt were evaluated and compaction parameters were tried to be determined. Simple and multiple regression analyzes were made with the help of the Eview program, where the statistical analysis of the existing data was made, and the statistical significance of the obtained models was examined by performing the F test. It was determined that higher correlations were obtained compared to other sample data, especially by using the data of samples that do not contain sand and gravel material.

Predicting the Saturated Hydraulic Conductivity of Clayey Soils and Clayey or Silty Sands

Predictive models able to provide a reliable estimate of hydraulic conductivity can be useful in various geotechnical applications. Since most of the existing predictive methods for saturated hydraulic conductivity estimation are valid only for a limited range of soils or can be applied under certain restrictive conditions, a new method applicable to clayey soils and clayey or silty sands having a wide range of values of soil index properties is proposed in this study. For this purpose, 329 saturated hydraulic conductivity values, obtained by laboratory tests carried out on different soils, were collected in a database and used to develop five equations using a multiple regression approach. Each equation correlates the hydraulic conductivity with one or more geotechnical parameters. An equation was developed that predicts, within an order of magnitude, the saturated hydraulic conductivity in the range from 1.2 × 10−11 to 3.9 × 10−6 m/s, based on simple geotechnical parameters (i.e., clay content, void ratio, plastic limit, and silt content).

Effect of mineralogical composition related to profile depth on index and strength properties of regolith soil

While chemical weathering is the most significant geochemical process that affects the engineering behavior of rocks, the fact that authigenic soils present different values of their physical and mechanical properties depending on the depth is also directly related to weathering. Although it is known that such variation is applicable for regolith soils with thickness reaching tens of meters, significant differences can be observed through the depth of residual soils with the thickness of only a few meters. Ignoring such aspects especially in sites with a high risk of landslide leads to many engineering problems. Therefore, Trabzon Province, which has the highest potential of landslide in Turkey, has been selected as the pilot area within the scope of this study. The variations in engineering properties of regolith soils, which have a depth of up to 15 m and are weathered products of volcanic rocks, have been researched as a function of geochemical properties. For this purpose, the data collected from borehole applications, geophysical surveys, in situ cone penetration tests (CPT), and standard penetration test (SPT) as well as laboratory experiments have been evaluated; and it is observed that physico-mechanical properties are directly based on geochemical variations. While the zones with low SiO2 and high Al2O3 and Fe2O3 values are characterized with high content of clay and cohesion, depths with low S wave velocity correspond to areas with the highest chemical alteration index values and the highest degree of weathering. And high liquid limit (LL) values correspond to areas with high illite content as well as high Al2O3 and Fe2O3 values. At these depths, high friction ratio values are observed in CPT results. Obtained data indicate that physico-mechanical properties vary as a function of the depth based on geochemical properties, and this suggests that the soil in projects with regolith soils needs to be separated into different layers and analyzed.