Plastic Limit Values Research Articles

Importance of geotechnical soil properties for precision Forest activities in a karst area

Some soil behaviors change significantly as water content varies over time. The particle size distribution of soils has a direct impact on mechanical properties such as soil water content, resistance to dispersion, swelling-shrinkage, fluidity, plasticity, and stickiness. This study was conducted to investigate the usability of Atterberg limits, consistency index and coefficient of linear extensibility (COLE) in the temporal planning of ecosystem restoration activities such as silvicultural interventions, tillage, afforestation, and the construction of forest roads, etc. Surface soil samples were collected from the sections numbered 263, 264, 266, 268, 317, 318, 319, 323, 324,325 and 366 of the degraded forest of the Andırın forestry operations department. The COLE, liquid limit (LL), plastic limit (PL), plasticity index and consistency index values of soil samples were determined. The LL values ranged from 17.5 to 62.4%, the PL values from 8.2 to 46.8% and the PI values from 6.4 to 15.5. The highest COLE value (0.13) was recorded in the section 318, while the lowest COLE value (0.03) was in section 325.The LL and PL values have a positive linear relationship with clay and organic matter content. All sections have karstic characteristics, but the mechanical characteristics of the soils differ significantly between the sections. Silvicultural interventions carried out especially in section 318, which had the lowest consistency index (Ic = 0.70), and sections 263, 264, 317 and 319, where the consistency index is >2,should take mechanical properties into account, and the planting time intervals should be determined, accordingly for sustainable forestry.

Modeling the Geotechnical Properties of Small Soil Samples of Oil Polluted Soil: The Power of Supervised Machine Learning Models

ABSTRACT Increasing levels of oil spills in both the terrestrial and aquatic environments destroy aquatic life and crops, fill the air with dangerous fumes, and change the physical and chemical features of the soil. Numerous authors have researched oil spills, but the application of supervised machine-learning models has been incredibly under-explored. Therefore, this study compared four supervised machine learning algorithms (Naïve Bayes Classifier, Decision Tree, Random Forest, and Support Vector Machine) to model the geotechnical properties of oil-polluted soil samples. The soil samples were collected from Engenni Ahoada in Rivers State and Izombe, Imo State, Nigeria. The samples were tested for the following parameters according to the ASTM standard method of measurement: shear strength (SS), liquid limit (LL), plastic limit (PL), bulk density (BD), maximum dry density (MDD), optimum moisture content (OMC), California bearing ratio (CBR), and plasticity index (PI). These measurements and the kind of soil (clay or laterite) constituted the inputs for the machine learning algorithms for predicting pollutant type (crude or diesel). The data from the thirty-two (32) sample size was split into train (70%) and test (30%) sets. The models were trained using the train set, and the test sets were used to validate the models. The support vector machine outperformed the competition, with prediction accuracy in the train and test sets of 96% and 89%, respectively. The findings demonstrated that the plastic and liquid limits are the most crucial factors for determining the pollutants in a sample of polluted soil. Also, plastic limit values less than or equal to 22 are likely contaminated by crude oil, while those above 22 are contaminated by diesel. The results therefore recommend using a support vector machine learning model for predicting the pollutant type of polluted soil samples in the study area.

Discussion: Development of a Single-Point Method to Determine Soil Plastic Limit Using Fall-Cone Data [Geotech Geol Eng 41:4473–4485, 2023

This discussion article presents a critical appraisal of three empirical correlations developed via multiple regression analysis and presented in the Kayabali et al. [Geotech Geol Eng 41:4473–4485, 2023. https://doi.org/10.1007/s10706-023-02527-0] (the Authors’) investigation for the determination of the soil consistency limits. Specifically, based solely on British Standard (BS) fall-cone (FC) test data, the Authors purport that the correlations given by Equations 2 and 3 of their paper can be used to predict the ASTM rolling-plate plastic limit (i.e., PLRP), while their Equation 4 can be used to predict the BS FC liquid limit (i.e., LLFC). The Authors demonstrated that these correlations gave good predictions of the measured LLFC and PLRP water contents (i.e., wL(FC) and wP(RP), respectively) for 87 fine-grained soils they sourced from different parts of Central Turkey. Employing newly compiled large and diverse consistency limits databases assembled from the published research literature, this discussion article confirms that the Authors’ Equations 2 and 3 generally produce poor wP(RP) predictions for the fine-grained soils comprising these databases, invariably overestimating (often seriously) their measured plastic limit values. Hence, the Discussers recommend that the Authors’ Equations 2 and 3 (being generally unreliable beyond the investigated Turkish soils) should not be used in geotechnical engineering practice. While the Authors’ single-point LLFC method given by their Equation 4 broadly appears as a good wL(FC) predictor for the newly compiled database soils, it is noted that there already exist well-established and standardised single-point LLFC methods.

Effect of temperature on the compressibility behavior of glass fiber-bentonite mixture

Effect of temperature on the compressibility behavior of glass fiber-bentonite mixture

The Effectiveness of Cement and Lime as Stabilizers for Subgrade Soils with High Plasticity and Swelling Potential

This study investigated the effects of cement and lime on the mechanical properties of subgrade soils, which are challenging to stabilize due to high plasticity and swelling potential. The study found that both cement and lime are effective stabilizing agents that increase the OMC, with cement being more effective in reducing the OMC of black cotton soil. The engineering properties of stabilized Chokocho subgrade soil were also evaluated, and the use of cement and lime as stabilizers was found to be effective in improving soil characteristics for subgrade applications. This was indicated by increased maximum dry density values, reduced plasticity index values, and increased California bearing ratio and unconfined compressive strength values. The chemical composition test demonstrated that calcium plays a significant role in soil stabilization, while aluminum can potentially affect soil stability negatively. Other elements such as magnesium, iron, silicon, zinc, and nickel contribute positively to soil stability. The low amounts of lead, copper, manganese, potassium, sulfur, and titanium present in the soil indicate a minor contribution to soil stabilization, but their impact on soil properties and plant growth cannot be ignored. Overall, the study highlights the importance of considering specific soil types and conditions when undertaking soil stabilization projects. The findings provide valuable information for future research in this field, particularly in investigating the effectiveness of other stabilizers and their interactions with specific soil types. The use of cement and lime in soil stabilization is an effective method for enhancing the strength and durability of weak soils, as shown by the reduction in plastic limit values observed in the stabilized soil samples. The appropriate content of cement and lime to use in soil stabilization could inform standards and codes for soil stabilization.

An Evaluation of a Marginal Land’s Geological Engineering Properties in Borikiri Sandfill, Port Harcourt Nigeria

Aim: The aim of this study was to assess the geological engineering properties of a marginal land in Borikiri Sandfill, Port Harcourt, Nigeria, using both field and laboratory investigations.
 Study Design: The study design involved the drilling of 4 boreholes and standard penetration tests to determine the soil profile and index properties such as particle size analysis, atterberg limits, and moisture content. Consolidation and triaxial tests were also performed to determine the values of the coefficients of permeability (k), volume compressibility (Mv), and consolidation (Cv).
 Place and Duration of Study: The Study was conducted in Borikiri Sandfill, Port Harcourt between February and May 2020.
 Methods: This study's methodology included field research, laboratory analysis, and testing. Drilling and conventional penetration tests were used to assess the soil profile. Laboratory tests such as particle size analysis, atterberg limits, and moisture content were used to determine the index characteristics. The values of permeability (k), volume compressibility (Mv), and consolidation (Cv) were also determined using triaxial and consolidation tests.
 Results: The results of the study showed that the soil profile consists of five stratigraphic sequences, with a top organic silty layer followed by a sandy layer, a dark plastic layer, a dark silty clayey sand, and a well-graded sand. The clays had an average Liquid limit (LL) of 45% and a Plastic Limit (PL) value of 23%. The values of k, Mv, and Cv were determined to be 2.1 x 10-7 m/s, 1.8 x 10-4–2.5 x 10-4 m2/MN, and 3.8 m2/yr, respectively. The average bearing capacity values at 2.5 m and 4.5 m depths were determined to be 186.39 kPa and 278.71 kPa, respectively. Settlement values were calculated empirically for immediate and consolidation settlement, with immediate settlement being high at 25.85 mm and consolidated settlement being 7.53mm. T50 and T90 values were also determined to be 1.32 and 4.52 years, respectively.
 Conclusion: It is recommended that a shallow foundation, down to the first layer, can be used for any light construction on the marginal land in Borikiri Sandfill, Port Harcourt, Nigeria. The values of k, Mv, and Cv also indicate that the soil is relatively compressible, which should be taken into account in any design or construction activities.

Multivariate regression approaches to predict the flexural performance of cellulose fibre reinforced extruded earth bricks for sustainable buildings

Regression analysis is commonly used to predict the compressive strength of soil-based materials to reduce the time and cost of construction projects. This study presents the results of multivariate regression analysis on the prediction of modulus of rupture and specific energy of cement-stabilised earth bricks reinforced with bamboo cellulose fibres as a function of cellulose fibre percentage, curing temperature and curing time. Statistical modelling is carried out on the experimental data of the four-point bending test of clay brick stabilised with 10 wt% Ordinary Portland Cement reinforced with 0, 5, 7.5 and 10 wt% organosolv bamboo pulp fibres. The water content of the unreinforced specimen was adopted at 25 wt% of the solid materials based on the plastic limit value of the soil, while the value of the water content of the samples with cellulose fibres was 35 wt% due to the affinity of the cellulose with water as well as to allow good extrudability of the pulp. The bricks were cured under different conditions (23 °C, 60% RH and 60 °C, 100% RH) and at different ages (14 and 28 days). Regression analysis and two-way ANOVA were studied to assess the accuracy, correlation and effect of each variable on the prediction of the random response variable. The results showed that non-linear regression analysis provides the best-fitting statistical model with an accuracy of 96%. In addition, the curing temperature and the percentage of cellulose fibres significantly affect the bricks bending performance, while the effect of curing time is the least visible. This non-linear model can be adopted as a suitable model to predict the flexural properties of cellulose pulp fibre-reinforced earth bricks for a sustainable building solution in developing countries. For better generalization and practical application of this method to predict the flexural performance of cellulose pulp fibre-reinforced earth bricks, a large data set of a broader range should be explored.

Black Cotton Soil: Results of an Experimental Study

After performance standards, economic feasibility and serviceability are the most crucial requirements for any project in developing nations like India. Time-consuming and costly, conventional approaches are no longer viable options. Consequently, it's important to identify different approaches to meet the performance and cost requirements that exist. The efficiency and low cost of these enzymes have been repeatedly demonstrated. The bioenzyme's eco-friendliness provides a further benefit. Dosage, soil type, and time allowed for cure all affect how effective bio enzymes are. Black cotton soils cover a considerable portion of our country. With the growing depletion and rising cost of traditional soil stabilisers like gravel, sand, and others, it is imperative that we find suitable, environmentally friendly alternatives. Soil stabilisation with bio-enzymes has become increasingly common and popular as a result of their low cost in recent years. Terazyme is one such bio-enzyme that has been utilised here. Unconfined compressive strength and atterberg limits were investigated as a result of Terazyme. Values for unconfined compressive strength have increased noticeably in soil that has been treated with enzymes. In its natural state, the soil has a compressive strength of 71 kN/m2. The soil's strength increased noticeably after being treated with Terazyme. The strength improves as time passes for cure. It was determined that there was a 300 percent increase in strength. Terazyme enzyme treatment did not result in a statistically significant increase in the liquid and plastic limit values. After being treated with enzymes for a short time prior to curing, both the compression index and the coefficient of consolidation decrease.

Mengidentifikasi Jenis Tanah, Batas Plastis, Batas Cair Tanah Lempung

Soil is a material consisting of mineral grains bonded to one another. Soil itself has various types. One of them is clay. Clay soil is microscopic soil particles that come from weathering rocks. The water content in clay tends to be high so it has a low bearing capacity. In addition, it also has a high shrinkage. Therefore, the management of clay soils must be handled properly. The method used is Gradation Sieve, Liquid Limit, and Plastic Limit. These three methods are considered suitable for conducting tests on clay samples. From these tests, obtained D10 values of 0.14, D30 of 0.5 and D60 of 1.6. And the results of the calculation of Cu and Cc obtained the values of Cu 4 and 1 Cc 3 so that the soil is classified into the GC group (well granded gravel with clay). For the results of the liquid limit test (LL) on the soil samples that have been studied, the average liquid limit value of 25 strokes is 41.12%. For the results of the plastic limit (PL) test on the soil sample, the plastic limit value of 32.42% was obtained. And the results of reducing the liquid limit with the plastic limit obtained a plastic index value of 8.70% so that the soil is included in the criteria for low plasticity index.

Penurunan Konsolidasi Tanah Lempung Kecamatan Sambi Kabupaten Boyolali yang Distabilisasi dengan Limbah Keramik

Based on the preliminary test results, the original soil of the Sambi Boyolali area is classified as inorganic clay with high plasticity. It has a plasticity index value of 31.93%, therefore stabilization is required so that the soil is able to withstand the load of the structure above it. Stabilization was carried out by mixing the soil with ceramic waste that passed the No. 4 sieve with variations of ceramic waste 2.5%, 5%, 7.5%, and 10% of the weight of the soil sample, which aims to determine changes in physical properties and mechanical properties (consolidation settlement) before and after the soil is stabilized. The results of the physical properties test of the soil after being stabilized with ceramic waste showed a decrease in the value of water content, specific gravity, liquid limit value, and plasticity index as well as an increase in the plastic limit value, shrinkage limit value and the amount of soil that passed sieve No. 200. Soil classification changed from inorganic clay with high plasticity in the original soil, to inorganic clay with low plasticity when mixed with 10% ceramic waste. The results of the mechanical test showed an increase in the value of the maximum dry volume weight of the soil (γdmax) as well as the value of the consolidation coefficient (Cv), and a decrease in the compression index value (Cc) and the consolidation settlement value (Sc).

Effect of low-density polyethylene, polyvinyl chloride, and high-density polyethylene micro-plastic contamination on the index and engineering properties of clayey soil- an experimental study

Soil health is one of the prominent features of the Sustainable Development Goals (SDGs). The SDGs seek to achieve the target of 75% healthy soils by 2030. On the contrary, the growing accumulation of microplastic contamination in soil environments is an issue of worldwide concern. The effect of a variety of microplastic accumulation on soil index and engineering properties is still unclear. Clayey soil is very important in geotechnical engineering because of its complex behaviour. This study investigates the effects of a variety of microplastics such as Low-Density Polyethylene (LDPE), Polyvinyl Chloride (PVC), and High-Density Polyethylene (HDPE) in environmental relevant concentrations (2%,4%,6% w/w) on index and engineering properties of clayey soil with respect to a number of observation days. In the present study, the non-contaminated soil treated as a control. The detailed experimentation revealed a significant change in the liquid limit, plastic limit, and shear strength values of clayey soil with an increasing percentage of microplastic contamination, whereas minute changes are recorded with respect to the number of observation days, this may be due to inert nature of microplastic. The shear strength is one of the critical engineering properties of soil that determines the strength and stability of the soil. The shear strength value of 0.94 kg/cm2 for control decreased to 0.76 kg/cm2 and 0.73 kg/cm2 and 0.85 kg/cm2 for the addition of 2%, 4%, and 6% respectively of LDPE microplastic contamination, similarly, for PVC microplastic contamination of 2%, 4% the shear strength decreases to 0.77 kg/cm2, 0.85 kg/cm2 respectively, the HDPE microplastic contamination of 2%, 4%, and 6% results in shear strength decrease to 0.52 kg/cm2, 0.53 kg/cm2 and 0.65 kg/cm2.The altered values of shear strength along with other index and engineering properties of soil due to microplastic contamination may lead to instability in structures or may increase the chances of harmful natural threats such as landslides. The present study provides evidence of significant changes in the index and engineering properties and therefore the stability of the soil which is the major contribution of the study.

State parameter governing the mechanical properties of cement-treated clays

A new state parameter that is capable of characterizing the mechanical properties of cement-treated clays with different mixing proportions, curing time, and stress conditions is developed in this study. The development is conducted by combining the effect of stress level based on the critical state theory with the effective void ratio. Based on the experimental data of cement-treated Bangkok clay performed in this study together with those of cement-treated Singapore marine and Ariake clays reported in previous studies, the analyses reveal that the state parameter is proven to be an efficient parameter for characterizing the mechanical properties of cement-treated clays with different base clays under various mixing proportions and curing times tested under various stress conditions. Furthermore, empirical equations to assist the establishment of the effective void ratio on the critical state locus from the plastic limit value of the base clay are suggested based on regression analyses. The state parameter can thus be computed and the engineers can preliminarily estimate the mechanical properties of cement-treated clay in the planning stage.

Mapping the Physical Properties of Soils and the California Bearing Ratio (CBR) Value for Different Soil Types: A Case Study in the Bukit Kemuning and Pugung Tampak Areas

It is widely accepted that soil is a mixture of mineral constituents that have accumulated over time. The physical characteristics of soil vary according to the mineral and organic matter content and the process of formation. The soil`s unique characteristics have been the subject of research in the field of civil engineering, which has continued to evolve to the present day due to the land`s requirement for civil engineering construction, such as road paving. As a result, the current study sought to determine the similarity of soil samples based on their physical properties and California Bearing Ratio (CBR) values, as well as the relationship between the soil`s physical properties and CBR values. To our knowledge, there is hardly little research in the literature investigating the topic under our investigation. Furthermore, we also mapped the physical characteristics and CBR values of numerous distinct soil samples using a Geographical Information System (GIS). This study concentrated on the West Lampung Regency, specifically the area between Bukit Kemuning in Central Lampung and Liwa in West Lampung, along the lines of Bukit Kemuning, Liwa, and Krui, all the way to the Lampung – Bengkulu province border. The soil samples from the area were taken for two tests: the unsoaked CBR test and the soaked CBR test. The results of the tests show that a 31-kilometre distance does not result in a significant difference in soil properties, which are generally similar except in clay-rich areas. Furthermore, the results of the laboratory analysis show that the amount of water in the soil sample affects the Liquid Limit (LL), Plastic Limit (PL), Maximum Dry Density (MDD), and CBR values; the lower the plastic limit value, and thus the lower the CBR value, the less water in the soil. The implications of the current findings are also discussed.

Influence of leachates on geotehnical and geochemical properties of termite mound soils

This study investigated the influence of leachate prepared from Telfairia occidentalis on the geotechnical and geochemical properties of termite mound soil obtained from the premises of the federal university of agriculture, Abeokuta, south-western Nigeria. The termite mound soil samples were collected from three different locations and each sample collected was contaminated by mixing with leachates in percentage increments of 0% 10%, 15% and 20% of dry weight of the air-dried soil. The soil samples were subjected to Atterberg limits and hydraulic conductivity tests for geotechnical observation and X-ray fluorescence tests for geochemical tests. The range of values for the geotechnical analyses were obtained as; plastic limit (9.1% – 14.2%), liquid limit (28.6 % – 61%), plasticity index ((18.2% – 49.5%) and hydraulic conductivity (1.85 – 4.1 x 10-8) cm/sec) with a resultant reduction in the plastic limit, liquid limit and plasticity index values but an increase in the hydraulic conductivity of the samples as the leachate concentration increased. The results from X-ray fluorescence analyses after 20% leachate contamination showed that the major elemental chemical composition for the three samples were comprised of SiO2 (56.25 – 56.5%), Al2O3 (28.42 – 28.50%), Fe2O3 (4.46 – 6.5%), TiO2 (1.08 – 1.23%), CaO (1.45 – 1.60%), P2O5 (0 – 0.04%), K2O (0.9 – 6.1%) and MnO (0.02 – 4.7%). There was a marginal alteration of the indices with the values inferring the presence of a minimum composition of feldspar and a major composition of quartz-rich minerals and thus lending more credence to the presence of silicates as shown from the X-ray fluorescence results. It also infers that the termite mounds are predominantly made from sand materials. The termite soil samples obtained from the aforementioned locations may not be suitable for engineering works unless stabilization procedure is adopted.

The Effect of Organic Waste and Synthetic Conditioner Applications on Consistency Limits

This study was carried out to determine the effects of wheat straw (WS), hazelnut husk (HH), humic acid (HA) and polyacrylamide (PAM) treatments on consistency limits (liquid limit (LL), plastic limit (PL), plasticity index (PI)) in two soils with sandy loam and clayey loam in texture. Soil samples used in the study were taken from two different areas of land (0-20 cm) from Samsun province's Bafra district. WS (0, 2%, 4%), HH (0, 2%, 4%), HA (0, 200 and 1000 ppm) and PAM (0, 30 and 90 ppm) were used in this study that was conducted in a split plots experimental design with three replications. According to the results; it was determined that the liquid limit, plastic limit and plasticity index values increased with the application of organic and synthetic conditioners in both soil texture, and the effect was realized as WS>HH>HA>PAM. It was observed that the highest dose application was the more effective in both soil texture, except for PAM.

Effects of vermicompost applications on Atterberg Limits and workability of soils under different soil moisture contents

The present research was conducted to assess the effects of vermicompost (VC) treatments under different soil moisture contents on consistency limits of sandy-clay-loam (SCL) soils in which lettuce (Lactuca sativa var. crispa) was cultivated in a greenhouse. Liquid limit (LL), plastic limit (PL), plasticity index (PI), consistency index (Ic) and clay activity (A) values were investigated. Three different VC doses (0, 2.5 and 5% w/w) were applied at 3 different soil moisture contents (100% FC-field capacity, 50% FC and 25% FC). Experiments were conducted in 3 replications over 27 experimental plots (3×3x3). Increasing LL and PL values were observed with increasing VC doses. The greatest LL (46.6%) and PL (37.7%) values were obtained from the 5% VC treatment under high soil moisture content (100%FC) and the lowest LL (35.0%) and PL (23.0%) were obtained from the control treatment under low soil moisture content (25%FC). LL had significant correlations with VC (0.848**), PL (0.904**), PI (0.565**), Ic (0.668**) and A (0.548**). Ic had significant correlations with VC (0.815**), PL (0.417*) and PI (0.740**). As compared to the control treatments, Ic values increased by 13.0% and 21.9% respectively with 2.5% and 5% VC treatments. Ic values were greater than 0.75. Therefore, it was observed that the sandy-clay-loam soils could be cultivated without any structural deformations at FC or higher moisture contents with vermicompost application. Moisture content upper limits for optimal tillage without any structural destructions were suggested as 26.8%, 34.9% and 36.9% for 0%VC, 2.5%VC and 5%VC treatments, respectively. Present findings indicated that VC treatments extended the range of moisture for workability.

Improvement in engineering properties of clay soil using waste demolished material

Expansive soil contain the highly active clay mineral in the form of montmorillonite due to which expensive soil swell upto 7% upon adding 1% of water, which may lead to unequal settlement of subsoil. The primary characterisation of clayey soil is which possess very poor shear strength with high shrinkage & swelling. This research paper represent a complete framework to overcome this drawback of highly expansive soil by adding waste material like fly ash and brick waste to clay soil in order to improve it’s engineering properties. Fly ash can be easily obtained from coal combustion plants while brick waste is easily available at demolition area. In this research fly ash is added in different percentages 0%, 4%, 8%, 12%, 16% and brick waste is added 5%, 10%, 15%, 20%, 25% by weight of soil. The results of test shown that the addition of fly ash and brick waste reduces the liquid limit, plastic limit value, plasticity index value, optimum moisture content value, percentage free swell index value and increases the unconfined compressive strength value and California bearing ratio value.

Investigation of Clayey and Sandy Soil Characteristics Polluted with Crude Oil

The focusing in this study was on the contaminated-uncontaminated soils' properties whichstudied by performing experimental tests included, Atterberg’s limit, specific gravity, compaction,unconfined compression, and direct shear tests. Different % of crude oil was used in thecontaminated soils which are performed by mixing the soils using different percent of were oilof 3 %, 6 % and 9 % by dry weight. The main effect of oil contamination causes a reduction in theliquid and plastic limit values for clayey soil. Besides oil contamination gives a reduction in themaximum dry unit weight as well as a decreasing the optimum water content with comparisonto original soil (clayey and sandy soil). The angle of internal friction is decreased for sand whileit increases for clay is one of oil contamination results.

Discussion: Determining the plasticity properties of high plastic clays: a new empirical approach [Arab J Geosci (2020) 13(11), 394

This article presents a discussion of the Arabian Journal of Geosciences, 394, Vol. 13, No. 11, which (among other things) proposed a new empirical correlation for the prediction of the plasticity index magnitude (and hence by association the plastic limit value) of fine-grained soils sampled from different depths in the Bakirkoy District of Istanbul City. As inputs, the proposed correlation employs the activity index, along with defining parameters of the semi-logarithmic flow curve obtained from the Casagrande (percussion-cup) liquid limit test. This article presents the following: (i) a discussion of the relevant literature that was not covered in the original paper; (ii) clarifications on, and observations regarding, the general approach adopted in the original investigation; (iii) concerns over whether the proposed new empirical correlation can be meaningfully recalibrated for particular clay soil types specific to other regions around the world; and (iv) suggestions for improvement of the new empirical correlation by adopting a different set of input parameters.

Bilecik Şeyh Edebali Üniversitesi Kampüs Topraklarının Bazı Fiziko-Kimyasal ve Mekaniksel Özellikleri ve İşlenebilirlikleri

In this study, some physico-chemical and mechanical properties and appropriate moisture levels for workability of soil series in Bilecik Şeyh Edebali University Campus area in Turkey were determined. Soil samples were taken from 0 - 20 cm depth of 20 different points in Gülümbe and Aşağıköy series. Soils in the Gülümbe were clay (C) and clay loam (CL) in texture with a mean bulk density of 1.05 g cm-3, saturated hydraulic conductivity of 0.66 cm h-1, slightly alkaline (pH=7.74), medium soil organic matter (SOM) (2.01%), high lime (17.08%), insufficient available phosphorus (1.92 kg P2O5 da-1), sufficient available potassium (88.54 kg K2O da-1), cation exchange capacity (CEC) of 37.71 cmol kg-1, insufficient available Fe (2.35 mg kg-1) and available Mn (5.18 mg kg-1), sufficient available Zn (1.81 mg kg-1) and available Cu (1.00 mg kg-1) contents. Soils in the Aşağıköy were loamy (L) and sand-clay-loam (SCL) in texture with a bulk density of 1.31 g cm-3, saturated hydraulic conductivity of 2.32 cm h-1, slightly alkaline (pH=7.74), low organic matter (1.81%), medium lime (6.75%), high available phosphorus (18.76 kg P2O5 da-1), sufficient available potassium (133.94 kg K2O da-1), CEC of 25.26 cmol kg-1, sufficient available Fe (5.67 mg kg-1) and available Cu (2.57 mg kg-1), insufficient available Mn (3.21 mg kg-1) and available Zn (0.66 mg kg-1) contents. While the highest liquid limit (LL) (68.17%) and plastic limit (PL) (31.49%) values were determined in Gülümbe series with the highest clay content and the lowest LL (46.50%) and PL (24.80%) values were in Aşağıköy series with the lowest clay content. Plasticity index (PI) of the soils in Gülümbe and Aşağıköy series respectively varied between 32.73 - 40.26% with a mean of 36.17% and between 21.70 - 28.0% with a mean of 24.73%. Based on LL and PI values, Gülümbe soils were classified as “highly plastic inorganic clays” and Aşağıköy soils were classified as “moderately plastic inorganic clays”. LL values of the soils had significant correlations with clay (0.88**), sand (-0.71*), PL (0.75**), PI (0.89**), consistency index (0.57*), SOM (0.62*), CEC (0.75**) and available K2O (0.54*). The upper and lower moisture limits for optimum tillage were recommended as 29.15 - 23.50% for Gülümbe series and as 24.95 - 21.24% for Aşağıköy series. It was concluded that campus soils could be cultivated at field capacity without any structural deformations because of the consistency index values were between 0.75 - 1.00.