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The consistency of fine soils is an essential tool in the classification and estimation of their parameters. Firstly, the changes in the consistency limits of the clayey soil improved with the waste material were investigated experimentally. Bentonite, which was classified as a high plasticity clay according to the unified soil classification system, was improved by using only waste glass powder, only waste EPS beads and both additives at different rates. Liquid limit and plastic limit tests were carried out. Secondly, a dataset (65 data) was gathered for the consistency limits of treated soils with similar waste materials in this study and literature. 80% of the data was selected to be used as training and 20% as a test dataset. Empirical correlations were obtained with the multiple linear regression method. The same dataset was used in the artificial neural network method (ANN) and the algorithm was trained. Both methods were run with the testing dataset and the results were compared. In both methods, the determination coefficients obtained from the training and testing data sets are satisfactorily high, and it is thought that the consistency limits of the treated clays will be estimated close to the actual values. In order to check that the results obtained by the ANN method are independent of the selected data sets, cross-validation tests were performed. As a result of this study, empirical correlations and ANN methods are proposed to be used in estimating the consistency limits of clayey soils improved with mentioned waste materials. [ABSTRACT FROM AUTHOR]

Pozzolans are used as additives in stabilizing clayey soils and as trass in cement production. Natural and unnatural pozzolans added to the ground in the stabilization process increase the bearing strength and strength of the soil, reduce the deformations that will occur as a result of stresses, settlements, swelling potential, liquefaction potential and permeability. It Pozzolans, which are used in cement and called trass, reduce the heat of hydration, increase the resistance of concrete against cracking, increase the waterproofing of the concrete and prevent the expansion caused by the alkaliaggregate reaction. For this reason, researching materials with natural pozzolanic properties and examining their pozzolanic properties are important for the country's economy. In this study, chemical and mineralogical studies were carried out to determine the pozzolanic properties of acidic and basic tuffs, and pozzolanic activity tests were carried out on the tuffs. As a result of the studies, although the acidic character tuffs belonging to the Kızılkaya Formation meet the conditions for use as an additive in the stabilization and cement production recommended in the standards, they cannot provide sufficient compressive strength in the pozzolanic activity test. This is due to the low CaO ratio. For this reason, it is necessary to increase the CaO ratio with lime additives in the use of acidic tuffs. It has been concluded that the chemical properties of the basic character tuffs of the Karabakır Formation are not in accordance with the limit values given in the standards, they will not create sufficient pozzolanic reaction and cannot be used as an additive material. [ABSTRACT FROM AUTHOR]

Sulfur (S) has an important place in meeting the nutritional needs of radish and obtaining high quality products. Biochar applications affect soil quality and plant growth positively. The study was carried out to determine the sulfur fertilizer demand of the radish plant grown in the calcareous soils at Konya that located in Central Anatolia, which has an important agricultural potential. In the study, it was aimed to determine the effect of biochar application on the plant's use of sulfur and plant growth, and the appropriate sulfur(S) fertilizer dose for radish. In the study, elemental-S (0-200-400 mgkg-1), SO4-2-S (0-25-50 mgkg-1) and biochar (0-1% - 2%) were applied to the cultivation soil. Plant material is 8TR-17 hazelnut radish (Raphanus sativus var.) variety. According to the results obtained, leaf chlorophyll SPAD values, plant height, tuber weight, the remaining S (mgkg-1) concentration in the soil at the end of the experiment were significantly different with increasing S doses compared to the control (p<0.01). Leaf chlorophyll SPAD values, plant height, tuber weight and the remaining S (mgkg-1) concentration in the soil(p<0.01) and stem diameter (p< 0.05) showed significant differences compared to the control at the interaction between biochar doses and S application forms. The chlorophyll SPAD value varied between 23.3and 34.8, leaf length varied between 5.59 and 6.49 cm, the number of leaves varied between 2.98 to 4.06 piecesplant-1 and leaf weight varied between 6.01 to 10.45 gpot-1. Stem length varied between 0.75 to 2.23 cmplant-1 and stem diameter varied between 1.5 to 15.24 cmplant-1. Tuber weight averages ranged from 0.136 to 4.566 gpot-1 and with the biochar applications increased compared to control. These increases are especially important in the SO4-2-S application. The remaining S (mgkg-1) concentrations in the soil are between 13.40 to 94.43 mgkg-1. These values showed significant differences with S fertilizers, S doses and biochar applications (p<0.05). At the soil pH value at the end of the experiment considering the mean values of sulfur doses, showed a decrease of 0.07 units compared to the control and this value was statistically significant (p<0.01). As a result, it is thought that good plant growth and tuber formation will be achieved with the application of 2% biochar in the cultivation of hazelnut radish, when the sand content is low and partially clayey loam soil will be used. [ABSTRACT FROM AUTHOR]

In this study, the removal efficiency of nitrogen and phosphorus in secondary treated wastewaters with a laboratory scale soil-aquifer treatment system prepared using two different types of soils and the effect of soil types on treatment efficiency were investigated. In the columns filled with clayey loam soil (CLS) and loamy soil (LS), secondary treated municipal wastewater taken from the effluent of Denizli province (Turkey) municipal wastewater treatment plant was used as feed wastewater. During the experimental studies, the total-N, total-P, dissolved oxygen, pH and temperature parameters were measured in the permeate samples taken from the valves at different depths attached to the columns. In the permeate samples taken from the last valves at a depth of 75 cm, total-N was 50.85% and total-P 97.07% in CLS, while these values were calculated as 36.72% and 64.43% in LS, respectively. In addition, the first 10 cm was highly effective for total-N and total-P removal in both soil types. Consequently, It was observed that TT was less effective than KTT in both total-N and total-P removal, the removal efficiency increased as the depth increased in both soils, and there was no time-dependent decrease in the removal efficiency during the experimental studies. [ABSTRACT FROM AUTHOR]

Evaluating and reusing wastes in the geotechnical field not only provides economical and effective solutions, but also contributes to sustainability by reducing the use of depleted resources. In this study, the effects of 0%, 5%, 10%, 15% and 25% waste porcelain tile (APK) on clay soils on the physical and mechanical properties of clay soils were investigated. APK reduced the liquid limit value of the clay soil by 25%, the plastic limit value by 22% and the plasticity index value by approximately 30%. With the addition of APK, the dry unit volume weight value increased from 1.71 g/cm3 to 1.74 g/cm3, and the optimum water content decreased by 15%. The CBR ratio increased from 4% to 10%, resulting in an increase in the transport value. It was concluded that by increasing the unconfined compressive strength by around 44%, it improved the bearing capacity. It was observed that the APK additive improved the consolidation properties of the clay and contributed positively to controlling the swellingcompression behavior. The consolidation coefficient value increased by 3 times with the increase in the APK ratio. The volumetric compression coefficient decreased by 90%. The permeability coefficient increased approximately 50 times with the increase in APK. In this study, it was concluded that it is possible to use APK to stabilize clayey soils. In addition to providing technical and economic benefits, the use of APK in the improvement of soils is a solution to the problem of accumulation of wastes in the environment and causing pollution. [ABSTRACT FROM AUTHOR]

The liquefaction phenomenon may originate in fine sandy - silty type of soils subjected to dynamic effects, low plasticity clays and even in soils with gravels based on the magnitude of applied acceleration. The mechanical or chemical soil improvement techniques have been used to prevent this problem. The mixing or grouting operations of sodium polyacrylate, which has a high-water absorption capacity, is one of the chemical soil improvement techniques. The frost behavior of this material, which turns into a gel form when react with the water in the environment, is not known in the permafrost areas. Within this purpose, sandy specimens including 5.00%, 10.00%, 15.00%, and 20.00% sodium polyacrylate gel as well as reference ones, were frozen at -20C° and unconfined compression tests were applied. Moreover, the tests were repeated for additional specimens containing 5.00% bentonite clay by weight. Although the unconfined compressive strength of all samples improved according to the increase in the amount of water with the gel content, about 14.00% lower values were obtained in specimens containing bentonite. On the other hand, the unit strain values of frozen samples without bentonite increased, while reduction observed in samples with bentonite. The viscous structure, that is in gel form inside the soil, dissipates volume increase during the freezing process and prevents the frost heave problem. However, the loss of bearing capacity should be considered in case of insufficient saturation in liquefaction sensitive sandy soils improved with sodium polyacrylate. [ABSTRACT FROM AUTHOR]

Response Surface Methodology (RSM) is useful to find the optimum value of the response, to examine the relationship between independent variables and responses, or to shorten very complicated and time-consuming numerical analyses. Although the RSM is a commonly used method in many branches of engineering, the use of this method is limited in geotechnical studies. In this study, the effect of curing temperature on shear strength and unconfined compressive strength parameters of lime stabilized clayey soil was examined. Within the scope of the study, it was aimed to evaluate the Response Surface Method to estimate these parameters with less experimental effort. In the study effect of the temperature was controlled with five different curing temperature level (3 °C, 13 °C, 23 °C, 33 °C, 43 °C). Three axial (UU) and unconfined compression tests were performed on 40 pieces of stabilized soil samples cured along 28 days at various temperatures. The experimental design was performed with Response Surface Methodology to reduce the test number. Within this scope, an equation was derived statistically to estimate the deviator strength of the samples. Statistical analyses were performed considering deviator strengths of the 18 pieces of samples. As a result of the study, it was seen that it is possible to estimate shear strength and unconfined compression strengths of the samples accurately by using fewer test numbers with Response Surface Methodology. [ABSTRACT FROM AUTHOR]

The use of geosynthetics as reinforcement for the base layer of flexible pavement systems has grown steadily over the past thirty years. Although geosynthetic reinforcements can lead to improved pavement performance, the specific conditions or mechanisms that govern the reinforcement are unclear, largely remaining unidentified and unmeasured. In this study, the assessment of the effect of geogrids on the roads that is reinforced granular fill layer over soft clay soil, section's ability to support before and after traffic loads were investigated using plate loading tests in situ. The results of the field tests show that geosynthetic reinforcement as is an effective method in reducing deformation and repairing granular fill layer overlying soft foundations. [ABSTRACT FROM AUTHOR]

In this study, liquefaction potential of the alluvial soils consisting of clay, silt, and sand sized materials in Sahilkent (Bafra, Samsun) area was investigated using CPT data. Within the scope of the study, 20 boreholes each having a depth of 15 meters were drilled throughout Bafra district, and one undisturbed soil sample were obtained per meter from 5 of these boreholes located in Sahilkent area. Wet sieve, hydrometer, plastic limit, liquid limit, and natural water content determinations were conducted on 20 samples with high silt and sand content. In the preliminary evaluation, it was determined that there is a liquefaction potential in some regions at different depths, and in order to perform detailed liquefaction analyses, 15-meter-deep CPTu were carried out in 1 meter distance from those 5 borehole locations. In CPTu tests, data including cone tip resistance, sleeve friction, effective stress, relative stiffness, etc. were recorded every 5 cm, and average values of these data for each meter depth were used in the liquefaction analysis. Liquefaction analyses was conducted for an earthquake scenario of Mw = 7.2 and the liquefaction potential of the 15-meter soil layer in the study area was determined. As a result of the analyses, it was determined that no liquefaction will occur for an earthquake scenario of Mw = 7.2 in Sahilkent region. It is thought that high fine-grained content of the alluvium, and the fact that existing clean sand levels are located between fine-grained soil layers increase the resistance of the soil against liquefaction. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to determine some engineering properties of the low plasticity clayey soil stabilized with ultrafine blast furnace slag cement (Spinor A6). Firstly, the fundamental geotechnical characteristics of clayey soil specimens stabilized with the contents of 8%, 10% and 12% ultrafine blast furnace slag cement were experimentally ascertained. Then, the compressive strength, compressibiliy and swelling tests were conducted on the ultrafine blast furnace slag cement stabilized clayey soil specimens that were compacted at the optimum moisture content and maximum dry density. Experimental data showed that after stabilization of low plasticity clayey soil with ultrafine blast furnace slag cement, its strength increased by 9 to 14 times in air dried samples and 9 to 12 times wet-cured samples after 90 days. In addition, at the end of the 90th day, compressibility decreased between 18.3 and 19.2 times in air dried samples and between 17.6 and 18.5 times in wet-cured samples. Finally, it was determined that the swelling potential decreased between 67.5 and 270.0 times in the samples that were kept in the air dried at the end of the 90th day and between 54.0 and 101.2 times in the samples that were kept in the wet-cured samples. Test results showed that the compressive strength of low plasticity clayey soil increased and its compressibility and swelling index decreased with time as ultrafine blast furnace slag cement was added to the soil. [ABSTRACT FROM AUTHOR]

In this study, an experimental research was conducted on the use of recycled concrete aggregates (RCA) obtained by pulverized of broken concrete samples which were used for determining the strength of concrete. Concrete samples were crushed in the laboratory and reduced to the required dimensions for the experiments. The clayey soil provided in the vicinity was chosen as the sub-base material to be used in road and embankment construction. RCA prepared by sieving 425-micron (No: 40) were mixed with sub-base soil at 5%, 10% and 15% thereby samples were prepared in different mixing ratios. Some geotechnical experiments were performed on the mixtures prepared to determine the effect of RCA on the water-density relationship and mechanical properties of clayey soil such as Proctor, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR). According to the results of the experimental study, RCA improves the mechanical properties of low plasticity clayey soil. [ABSTRACT FROM AUTHOR]

Chemical stabilization is defined as modification of engineering properties of soil with chemical reactions of various additives. Chemical stabilization is applied to the soils which cannot be adequately treated by mechanical stabilization. Chemical stabilization leads to changes in soil properties such as strength, plasticity, compaction and durability, as well as in its permeability. Permeability of soil is important in ground water flow and leakage problems. However, there are few studies about the effect of chemical stabilization on permeability. In this study, the effects of chemical stabilization with lime and perlite combinations on permeability of high plasticity clayey soil were investigated. With the stabilization of high plasticity clayey soils with lime, the permeability of the mixture increases up to 25 times. Moreover, perlite which can be used as a secondary additive in stabilization of such soils causes serious decrease in permeability. [ABSTRACT FROM AUTHOR]

Irrigating the soil with irrigation water, which has a high sodium concentration, usually increases the sodium content of the soil. The salt and the Sodium Absorption Rate (SAR) values of irrigation water cause significant changes in the physical structure of the soil. In the clayey soil, limiter variable amount of Na is specified as 1 - 1.5 meq 100-1 g soil, which corresponds to 4-8 Exchangeable Sodium Percentage (ESP) value. In this study, the effects of some parameters such as ESP, EC and pH of irrigation water with constant EC values and 0, 15, 30, 40 SAR values were investigated. During the experiment, 3 replicates were used from each subject and soil samples were taken at the end of the experiment from each layer. ESP values were found with divided into total Na to total Ca, Mg, K and Na values. EC and pH values were obtained by extracting soil samples from the laboratory and measuring them with EC and pH measuring devices. As the SAR values increased, the ESP values increased and statistically significant differences were observed between the soil layers. The highest ESP value averaged 4.124 on the third layer of SAR40, while the lowest ESP value was 1.312 on the second layer of SAR0. As the SAR values increased, EC and pH values increased, statistically significant differences between the layers were observed. [ABSTRACT FROM AUTHOR]

The most important soil behaviour in order to consider in foundation designs of specially light structures built on clay soils is swelling properties of the soil and accordingly soils heave which occurs on soil surface. For this reason, in surveys related to this kind of soils, it is quite important to determine the swelling properties of soils and appropriate stabilisation methods. Literature contains a vast number of stabilising techniques such as; lime, cement, fly ash, bitume and resin for treatment of expansive soils. Financial perspective of these techniques is very important. Therefore, the primary purpose is low cost for the best treatment. In this study, a laboratory model study was conducted in order to determine the performance of gypsum column technique on treatment of clay soils. For this purpose, gypsum column was built in a field model which built in the laboratory and the changes on swelling of the soil was determined depending on the distance from the column. By using the obtained model data, the performance of gypsum column technique was analyzed and discussed. [ABSTRACT FROM AUTHOR]

Many researchers investigated the behavior of surface foundations constructed on reinforced sand (Omar et al. 1993; Khing et al. 1993; Yetimoglu et al. 1994; Das ve Omar 1994; Adams & Collin 1997). However most of the problematic foundation soils are of cohesive nature. Therefore in this study the effect of reinforcing cohesive foundation soils was investigated. Normally the cohesive soil excavated would be replaced by a granular fill. This means that improvement will be obtained due to the geosynthetic reinforcement but also because of the soil exchange. In order to see the effect of geosynthetic reinforcement alone, in this study the backfill was considered to have the same properties as the natural cohesive soil. The foundation behavior is assessed using limit equilibrium and finite element method (FEM). In this study the finite element code, Plaxis was used. A parametric study was conducted. Safety factors were calculated by using the "Phi-c reduction" method in the finite element analyses. In the "Phi-c reduction" approach the shear strength parameters tanθand c of the soil are successively reduced until failure occurs. The soil was modeled as Mohr-Coulomb model and the reinforcement as a linear elastic material. In the analyses, no specific interaction model between soil and reinforcement was used. The analyses presented in this study involve strip foundations on clay soil. The problem was analyzed under plane strain condition. The material properties were chosen in accordance with those in the literature to represent a clay soil. The soil parameters adopted were: γ = 15 kN/m³; E = 25000 kPa (500 * c); ? = 0.30; Ş= 0°; ψ? = 0°and c = 100, 75, 50, 37.5, 25, 12.5 kN/m² . Footing thickness was chosen as 0.143 m and was placed directly on the surface without any embedment. Geosynthetic axial stiffness per unit width was selected as J=2000kN/m to represent a typical geogrid (Deb et. al. 2007). For the finite element analyses, vertical boundary was chosen to have only horizontal fixity and bottom boundary has both horizontal and vertical fixity. The size of the finite element mesh used was the same for all the analyses. It was chosen to be large enough to reduce the boundary effects to a negligible level. Factor of Safety (GS) for bearing capacities of unreinforced soil were calculated first by Limit Equilibrium analysis and then by FEM. The footing width (B=2.5, 5, 10 and 20 m), cohesion of the foundation soil (c=50 and 100 kPa), and surcharge load on footing (100 and 200 kPa) were varied to assess their influence on the safety factor of the shallow foundation. A good agreement was achieved between bearing capacity calculated using limit equilibrium approaches and finite element solutions. The finite element analysis gave factor of safety values directly proportional to cohesion of the clay soil as expected. In order to investigate the influence of the reinforcement on the factor of safety, a parametric study was conducted using different reinforcement configurations. Number of reinforcement layers, depth of the first reinforcement, vertical spacing of reinforcement layers, width of reinforcements and cohesion values of soil were chosen as variables in the analyses. Results obtained are summarized below: •As the number of reinforcement layer increases (from one to six), the safety factor increases as well. Regardless of total number of reinforcement layers, the foundation width did not have a significant effect on the bearing capacity. •The depth of the first reinforcement varied between 0.05B and 0.7B. The most efficient initial reinforcement depth was found as 0.4B. •The vertical spacing between horizontal reinforcement layers (H) were taken as 0.025B, 0.05B and 0.1B. When six reinforcement layers were used, increase in the factor of safety values were calculated as: 7.5%, 12% and 17% for H/B values of 0.025, 0.05 and 0.1 respectively. •The reinforcement lengths analyzed were L=B; L=2B; L=3B; L=4B and L=5B. The increase in bearing capacity after a length of L=3B was negligible. •BCR and effective reinforcement depth were not affected when cohesion of the soil changed. [ABSTRACT FROM AUTHOR]

This study was carried out in Gölbaşı-Harmanlı (Adıyaman) region where coal basin exists. Chemical, petrographical and organic geochemical analyses of the Tertiary aged coals were taken into consideration. Coal quality investigation along with proximate (moisture, volatile matter, fixed carbon, ash) and elemental analyses (C, H, O, S, N) were performed. The huminite reflectances of organically abundant matter and coal levels were found to be between 0.28% and 0.516% which refer to low maturity levels. This parameter is compatible with fluorescence colors, calorific value (average original 2736 - dry 3727 Kcal/kg) and average Tmax (422 °C). Organic matters of the investigatedcoals exhibit a low grade transformation, due to a low lithostatic pressure on them. In GC analyses, n-alkanes with low carbon numbers as n-C17, n-C27, n-C30 and n-C3 and CS2 as well as benzen were detected. Triterpanoid component was determined with GC-MS data and tends to imply high ground continental vegetation, but gammacera values to hypersaline depositional conditions. Gölbaşı coals show sub-bituminous and lignite coalification ranks. Rock Eval analysis results show TYPE II/III and III kerogen, with average Tmax value is 422 °C, and corresponding to the immature and premature rank for hydrocarbon generation. The coals are characterised with their abundance of huminite maceral group with small amount of inertinite and liptinite macerals. Mineral matters of the Gölbaşı coals are calcite, clays, and sulfur bearing minerals. [ABSTRACT FROM AUTHOR]

This study aims to compare the permeability coefficients calculated based on the particle size analyses peculiar to the soil samples of some districts at Meşelik and Tepebaşı residential areas in Eskişehir. The study area covers 6 km2. In this study, the properties ofunits in alluvial deposit cut by 29 boreholes previously drilled in the area were examined from borehole logs contained in the geological reports. On the basis of the sieve analyses, particle size distribution curves were drawn. The parameters of D60, D50, D30, D20, D10, I0, U, Cc values were calculated by using these graphs. Porosity values werecalculated by using Gs, specific density and water content. Permeability coefficients were also calculated for the units having no water content values considering the intervals accepted by the literature. Dependently or independently on porosity values, permeability coefficients were individually calculated by using the Hazen, Kozeny-Carman, Breyer, Slichter, Terzaghi, USBR and Alyamani-Sen formulas, for each core samples from different depths of the boreholes and then the most appropriate formula for different depths and units was determined. Variations of permeability coefficient for different grain sizes and porosities were studied. Based on the outcomes of this study, calculated permeability coefficients are almost similar for uniform soil units, however, different for non-uniform units. It is inferred that using above-mentioned approaches for estimation of permeability coefficient for clay material is not suitable. As a conclusion, estimation of permeability coefficient using Breyer, Slitcher, Terzaghi and Alyamani-Sen approaches are more suitable for non-uniform units while Hazen, Cozeny-Carman ve USBR are applicable for uniform units. [ABSTRACT FROM AUTHOR]

Liquid limit is one of the important soil index parameters and it is determined by means of two standard methods; Casagrande and fall-cone methods. Determination of liquid limit by fall-cone is based on penetration of cone shaped metal object into a homogeneously prepared soil mud with free fall. Even though it is less operator dependent and it gives more accurate results, compared to the Casagrande method, standard 4 point fall-cone method as imposed in TS 1900, takes long time when too many samples are to be tested for identification purposes. In this study 138 clay samples were tested with fall-cone method, test results were evaluated statistically and determination of liquid limit by means of one point fall-cone was investigated. After the experimental and statistical studies, 3 empirical equations were developed and “LL= W/(0.33* P/20)+0.66)” equation seemed to be more reliable. Faults to happen during the application of standard 4 point method are reflected on the graph and after drawing a trend line, these faults will be distributed along the trend line. However in the one point method faults will be reflected directly on a single liquid limit value. Therefore, in one point method, test procedure should be obeyed carefully. Although the fall-cone liquid limit test method is proposed method in Turkish Standards, one point method is not mentioned. As in the standards of other countries, it is thought to be appropriate that Turkish Standards include one point fall-cone method. [ABSTRACT FROM AUTHOR]