Sandy Silt Soil Research Articles

Investigating the internal erosion behavior and microscopic mechanisms of chemically stabilized soil: an experimental study

IntroductionInternal erosion triggered by water pipeline leaks seriously threatens the stability of the urban ground. Hangzhou, a city in Zhejiang Province, China, is facing critical challenges due to urban ground collapse (UGC) caused by internal erosion. However, there is a lack of research on the prevention of UGC by improving the internal erodibility of underground soil. Addressing this issue is of utmost importance to ensure the city’s stability and safety. This paper proposes to improve the internal erodibility of typical sandy silt soils with chemical stabilisers.MethodsThe effects of three chemical stabilisers, lignosulphonate (LS), lime (LI), and lignin fibre (LF), on the critical shear stress (τc) and erosion coefficient (kd) of sandy silt soils were investigated, which from Hangzhou, Zhejiang, China, by the hole erosion test (HET) at different mixing amounts and at different conservation times.ResultsThe findings indicate that LF mainly improves the erosion resistance of sandy silt by increasing τc, and the maximum increase is 2.38 times; LI mainly improves the erosion resistance by decreasing kd, and the maximum decrease is 2.18 times. After adding LS, τc and kd did not change significantly. The scanning electron microscope (SEM) test revealed that the inclusion of LF led to the formation of larger agglomerates in the sandy silt soil. The microstructure of sandy silt soil remained dispersed even after adding LS. Various chemical stabilisers used to improve sandy silt soils exhibited distinct erosion mechanisms. Sandy silt soils improved with LF exfoliated into agglomerates, displaying high resistance to erosion. On the other hand, the sandy silt treated with LF still lacks a protective layer and shows minimal improvements in its ability to withstand erosion. In contrast, the LS-amended sandy silt remains stripped with individual soil particles with insignificant changes in erosion resistance.DiscussionThis study can provide a conceptual framework for choosing foundation treatment techniques in future urban development projects.

Safety Factor and Settlement Analysis of Borepile Foundation in Warmadewa Gianyar Hospital Building

Building structure planning must be distinct from foundation structure planning. The foundation plays an important role in transferring building loads to the ground. The Warmadewa Gianyar Hospital building consists of 5 floors with a building area of 8323. 471 m2 on a granular soil location where there are three layers of soil types, namely sandy silt soil, silty sand, and sand mixed with rock grains. The Borepile foundation is installed at a depth of 12 m with an N SPT value of 60. This building carries dead loads, live loads, rain loads, wind loads, and earthquake loads. This building will use a bore pile foundation by modeling bore pile piles in GEO5 software to obtain safety factor values and installed reinforcement. Based on the analysis results, the pile diameter used is 450 mm and has a length of 12 m. The analysis obtained the carrying capacity with a safety factor of 2.1> 2 and a maximum settlement of 4.77 mm.

Erosion Mechanisms in Unpaved Roads: Effects of Slope, Rainfall, and Soil type

Erosion is the main cause of damage to unpaved roads. This study utilized rainfall simulators to quantify erosion on unpaved roads, controlling variables such as rainfall intensity and slope. A laboratory model of an unpaved road was utilized to evaluate soil loss in an experimental setup. A total of 72 tests were conducted to compare simulated conditions on unpaved roads for three soil types with three slope variations, and eight rainfall intensities. The impact of each variable (soil type, slope, and rainfall intensity) on soil loss was analyzed for 30-minute rainfall events. Analysis of variance (ANOVA) was employed to assess soil erosion response to terrain slope for the three soil types, revealing statistical differences in soil loss between low slopes (2%) and steep slopes (7%) with p-values of .04 (sandy soil), .00007 (sandy silt soil), and .00008 (loam silt soil). Correlation analysis demonstrated a strong relationship between rainfall intensity and soil loss ( R2 = .76) for sandy soil and sandy silt soil. Analysis of covariance (ANCOVA) indicated a linear relationship between soil loss and rainfall intensity, with significant differences ( p < .05). The findings suggest that soil loss on unpaved roads is positively correlated with slope and rainfall intensity. However, this relationship is not always linear; sandy soil exhibited a nonlinear relationship, especially with high rainfall intensities, whereas sandy silt soil showed a linear relationship with evaluated rain intensities. The type of soil influences erosion process, with higher erosion rates observed in sandy silt soils compared to loam silt soils. This paper analyzed the factors essential for addressing erosion on unpaved roads, identifying key elements to minimize soil loss.

Composition and Content of Carotenoids of Gastropod <i>Tritia reticulata</i> in Black Sea

The results of a two–year study of the composition and content of carotenoids of sea snails Tritia reticulata (L., 1758), living in a mixed bottom community of bivalve mollusks in the sandy zone of the upper sublitoral (depth 0–1 m) of the Cossack Bay of Sevastopol, are presented. The highest content of total carotenoids was detected in June (1.8–2.09 mg/100 g of crude mass), the average Cossack Baymples for both years was 1.54 mg/100 g of crude mass. In the qualitative composition of T. reticulata taken from the pastures of bivalves on sandy-silt soil, 15 free carotenoids were identified: b-carotene, echinenone, hydroxyechinenone, astaxanthin, didehydroastaxanthin, diadinoxanthin, diatoxanthin, fucoxanthin, halocintiaxanthin, fucoxanthinol, mactraxanthin, heteroxanthin, lutein, zeaxanthin, alloxanthin and esters of the last 4 carotenoids. The po-ssibility of metabolic transformations of carotenoids is discussed.

Quantitative analysis of selenium species in the edible parts of cabbage, carrot, tomato and green pea treated with selenate-enriched irrigation water

Background and aimsSelenium (Se)-biofortified foods are able to compensate for Se deficient diets, but the proportion of different Se species varies among plant species, and the bioavailability of Se species also varies. This study aims to examine the Se species composition of four vegetables.MethodsThe effect of Se-enriched irrigation water on the concentrations of Se species in the edible parts of cabbage, carrots, tomatoes and green peas grown on different soil types was investigated and quantified using HPLC-ICP-MS with either standard addition or isotope dilution.ResultsCabbage leaf and carrot root contained a high proportion (88 and 92%, respectively) of selenate (SeVI), while in tomato fruit and green pea seed selenomethionine (SeMet) was found in the highest proportion (33% and 48%, respectively), but elemental Se was also detected. The elemental Se concentration of peas was significantly higher on sandy soil (2.29 mg kg−1) than on sandy silt (1.38 mg kg−1) or silt soil (1.34 mg kg−1). In 100 g of fresh edible parts, the largest amount of Se species was found in cabbage leaves, but organic Se in the form of SeMet was the most abundant in green peas, being significantly higher than in carrots or tomatoes. Tomatoes contained a nearly three-fold ratio of organic Se to inorganic Se, the latter being mostly comprised of the elemental form, which is unusually high in vegetables. The highest rate of unknown Se species exceeded 66% in the case of peas, while the highest identification rate (> 95%) of Se could be achieved in tomato.ConclusionTomatoes converted the absorbed Se into organic Se in the highest ratio, while green peas had the highest amount of organic Se in fresh biomass, so biotransformation was the most effective for these vegetables without any significant biomass reduction. These vegetables may be adapted to soils with a higher Se content.

Exploration and isolation of indigenous arbuscular mycorrhizal fungi in post-landslide sandy and clayey silt for eco-friendly remediation

Critical lands are formed after landslides due to the erosion and stripping of the surface soil in the depletion zone and the formation of accumulation zones, requiring remediation efforts. Indigenous arbuscular mycorrhizal fungi help rehabilitate degraded lands, including post-landslide sites, by adapting to native soil conditions. This study investigates mycorrhiza’s presence in post-landslide areas with sandy silt in Cililin and clayey silt in Citatah. Soil samples are collected at 30 cm depth using a corer near Dysoxylum macrocarpum in Citatah and Gmelina arborea in Cililin. Mycorrhiza isolation involves wet sieving and centrifugation. Local mycorrhiza genera identified are Glomus, Gigaspora, Acaulospora, and Scutellospora. Sandy silt soil 2 exhibits the highest spore density of 178 per 100 grams, while clayey silt soil 1 has the lowest density of 148 per 100 grams. Glomus dominates in sandy silt with a 93 per 100 grams concentration and a 38–45 µm size. Scutellospora is scarce in clayey silt, with only 1 per 100 grams, 90-170 µm size. Isolated mycorrhiza can serve as compatible and adaptive inoculum. The discovery of mycorrhiza tolerant to post-landslide conditions is expected to play an important role in the remediation process of critical lands caused by landslides.

Experimental Study for Load-Settlement Behavior of Flat and Shell Footings on Sandy Silt Soil

Shell foundations are often used to raise the carrying capacity of a structure on weak soils. In cases where large superstructure loads must be transferred to poorer soils, shell foundations are more cost-effective than ordinary shallow foundations. Advances in the study and design of shell-type foundations have shown their superiority over traditional footings in poorer soils. The current study aims to investigate shell shape’s influence on ultimate load capacity. Seven footing types’ models were created along with an appropriate testing box. The soil needed for the study was from the region north of Mosul city, classified as silt with low plasticity (sandy silt) soil. A laboratory model experimentally determined the ultimate load capacities for inverted and upright conical, inverted and upright pyramid, and hemispherical shell foundations on silty soil. The achieved results were associated with those for conventional flat squares and circles. According to the findings, the “upright conical” shell footing has a load capacity of 12.7 kN, higher than the other foundations, and its efficiency was 51%. When comparing foundations, the “upright pyramidal” shell footing has better settling characteristics and a settlement factor of 0.017. As the shell factor decreases, the shell foundation begins to behave more like a flat foundation, which reduces the maximum load capacity of the shell foundation.

Experimental Data and Modeling the Adsorption-Desorption and Mobility Behavior of Ciprofloxacin in Sandy Silt Soil

The improved understanding of the behavior of antibiotics in soil is of great importance due to their environmental hazard and frequent detection. In this work, the adsorption-desorption and mobility behaviors of ciprofloxacin in sandy silt soil, affecting the fate of ciprofloxacin in the environment, were studied by a series of batch tests and column tests. In batch tests, the effects of contact time, initial ciprofloxacin concentration, sandy silt soil dosage, solution pH, and ionic strength on ciprofloxacin adsorption and desorption in sandy silt soil were considered. Adsorption results were satisfactorily modeled, with good fittings to the pseudo-second-order model (R2 > 0.999) and Langmuir model (R2 > 0.991), with the value for Langmuir’s maximum adsorption capacity (qm) 5.50 mg g−1. Ciprofloxacin adsorption decreased sharply by increasing the pH from 7.0 to 10.0 and the ionic strength from 0.01 to 0.2 mol L−1 CaCl2. Comparatively, ciprofloxacin was more readily desorbed from sandy silt soil at alkaline and high ionic strength conditions. Breakthrough curves of ciprofloxacin obtained from the column experiments were described by the two-site model, Thomas model, and Yan mode. Of these models, the two-site model was the most suitable to describe the mobility of ciprofloxacin. The retardation factor (R) obtained in the two-site model was 345, suggesting strong adsorption affinity with ciprofloxacin on the sandy silt soil surface. The results from the Thomas model suggested the extremely small external and internal diffusion resistances. The Yan model was not suitable. Cation exchange interaction, electrostatic interaction, mechanical resistance, entrapment between porous media, and gravity sedimentation were proposed to be the important adsorption mechanisms.

Hydraulic conductivity predictive model of RHA-ameliorated laterite for solving landfill liner leachate, soil and water contamination and carbon emission problems

AbstractThe environment is seriously being affected by the leachate release at the unconstructed and badly constructed waste containment or landfill facilities around the globe. The worst hit is the developing world where there is little or totally no waste management system and facilities to receive waste released into the atmosphere. This research work is focused on the leachate drain into the soil and the underground water from landfills, which toxicifies both the soil and the water. Also, the construction of the liner or barrier with cement poses serious threat to the environment due to oxides of carbon release and this research also took this into account by replacing the utilization of cement with rice husk ash (RHA), which has proven to have the potentials of replacing cement as a supplementary binder. Laboratory tests were conducted to determine the hydraulic conductivity (K) of lateritic soil (LS) ameliorated with different dosages of RHA. Other hydromechanical properties of the treated blend were studied and multiple data were generated for the artificial neural network (ANN) back-propagation (-BP), genetic algorithm (GA) and gradual reducing gradient (GRG), genetic programming (GP) and evolutionary polynomial regression (EPR) prediction exercises. Results show that the LS was a poorly graded A-2 sandy silt soil, which was subjected to three different compaction energies with the minimum of the British standard light (BSL) and derived k of 6.95E-10, 50.75E-10 and 32.33E-10 for BSL, west African standard and British standard heavy, respectively. The RHA addition improved the studied properties of the ameliorated LS. Out of the five models, the ANN-GRG outclassed others with a performance of 99% with minimal error compared with the rest. Potentially, this research has shown that RHA with a pozzolanic chemical moduli of 81.47% can replace cement in the construction of ecofriendly and more efficient landfills and waste containemnt barriers to save the soil and the underground water as well as the environment from leachate contamination and carbon emissions.

Effect of curing time and percentage of additive materials on unconfined compressive strength and California bearing ratio in sandy silt soil

Effect of curing time and percentage of additive materials on unconfined compressive strength and California bearing ratio in sandy silt soil

The soil characteristics mapping of Pagar Alam City (A case study of North Pagar Alam District)

Pagar Alam city is one of districts in South Sumatera province that has an area of ± 63,366 hectares (Monograph of the city of Pagaralam, 2013). So far, the people of Pagar Alam city, especially the north Pagar Alam district, have no reference to determine the soil type of its area; therefore this study carried out an analysis of the soil characteristics and conducted a mapping of its types of characteristics and the soil water content in the north Pagar Alam district.A geomap is a map that depicts existing image of the earth’s surface which is represented on a flat surface in a certain projection. Geomapping is a process of measuring, calculating and depicting the earth’s surface using certain methods. Soil is the surface layer of the earth that comes from parent material that has undergone an advanced process, due to natural changes under the influence of water, air, and various kinds of organisms, both living and dead (Dokuchaev 1870).After conducting 20 soil sample tests, it can be seen from the interpolated and overlayed sub-district map that the land in North Pagar Alam district has sandy silt soil where 19.69 km2 of the area has good grades of the soil and the other23.90 km2 of the area consists of poorly graded sand.

A Laboratory Methodological Proposal for “Geotechnical Lime Stabilization of A-4 Soils”

This paper establish the beginning of a research process regarding the behavior of soils stabilized with lime. Generally, the geotechnical practice of soils stabilized with lime requires a first step conducted in the laboratory, to attest the features of “natural soils” in order to improve their behavior in term of geotechnical performance and, a second step, carried out onsite with experimental test fields, in order to verify the benefit obtained by the use of lime treatments. The topic of this research focuses on the first step above described. In order to provide geotechnical laboratory tests useful to our purpose, A-4 soils (according to HRB classification) and CL-ML (according to USCS soils classification) were tested. These soils show a large distribution in the Piedmont Po Plain (NW Italy): they outcrop in correspondence to terraced alluvial fans linked to alpine watercourses and are generally applied for stabilization with lime for foundation structures and pavements. Additionally, these soils are mainly inorganic with a marked tendency towards sandy silt soils with the presence of gravel. The presence of gravel results on a greater strain hardening in the behavior of shear strength of soils. Finally, in support of geotechnicians, who have to draw up specifications, a systematized laboratory methodology to follow for A-4 soils stabilization with lime is here reported and a detailed analyses of mechanical behavior obtained on “soil-lime-water mixtures” is described.

Evaluation of time response of GMS for soil suction measurement

The Granular Matrix Sensor (GMS) is an indirect method for soil suction measurement. Since GMS is comparatively inexpensive, robust and usually provide continuous soil suction data, it is a natural candidate for civil engineering practice. The sensor has been used mainly for irrigation purposes, and also for some civil engineering activities. Questions about its effectiveness and reliability are still posed, making studies about this topic desirable. This study presents a laboratory comparison between Watermark and an ordinary tensiometer during an equilibrium period and for a wetting procedure performed in a compacted sandy silt soil (residual soil of gneiss). The results yielded that GMS may provide tensiometer equivalent suction values in a context of no significant water content variation. However, it takes a longer time to obtain stabilized suction values. During the wetting procedure, GMS presented a delay of about 2 h in detecting water while tensiometer detection was almost instantaneous.

Revisiting biotic and abiotic drivers of seedling establishment, natural enemies and survival in a tropical tree species in a West Africa semi-arid biosphere reserve

Biotic and abiotic drivers of seedling establishment and survival are fundamental not only for elucidating processes occurring at plant early life stages, but also for assisting species natural regeneration. Keystone, multipurpose and economically important tree species such as Afzelia africana Sm. are reportedly facing recruitment constraints, yet little is known about how abiotic and biotic factors shape the species seedling dynamics. Here, we monitored the species seedlings over one year across three seasons in West Africa savannahs to determine how conspecific and heterospecific biotic neighborhood and habitat heterogeneity correlate with initial seedling density, leaves’ fungal infection and herbivory and how all these factors combined, influence the species seedling survival.Seedling densities increased with increasing conspecific adult densities, and were highest in tree savannahs and on sandy-silt soils. Leaves’ fungal infection and herbivory were also positively associated with conspecific adult density, but were more abundantly observed in tree savannahs than in shrub savannahs. Seedling survival was constrained on higher slope, and negatively affected by conspecific adult density, especially in shrub savannahs.There was a strong evidence for negative density-dependence effects of conspecific adults on seedling survival, which operated through negative effects of herbivory and fungal infection. Habitat heterogeneity was also an important driver, which modulated biotic factors’ effects on seedling survival: tree savannahs promote positive conspecific density-dependence of seedling fungal infection and herbivory more than shrub savannahs. Nonetheless, seedlings were more sensitive to natural enemies in shrub savannahs, suggesting increased negative conspecific density-dependence effects on seedling survival in less dense vegetation, possibly as a result of enhanced specialization of predators and pathogens on a limited set of species. The study brings important insights into the mechanisms that drive the establishment and survival of the species seedling, which should be considered in the design of management activities aiming at the conservation of this endangered species.

Correlation Between SPT and PMT for Sandy Silt: A Case Study from Kuala Lumpur, Malaysia

In this study, the pressuremeter modulus (EM) and the unload–reload modulus (Eur) consisted of a wide range of data were correlated to blow counts (N60) using a maximum of 50 blows/300 mm and the extrapolated N60 of 300 blows/300 mm. A 3D model and statistical analysis were used to provide relevant justifications for the selection of this extrapolation method, considering that N60 was limited to 50 blows. In generating a 3D model, the N60 profile was developed using the inverse distance weighting method for predicting unsampled data between boreholes. Correlations were established for the sandy silt soil type that was observed as the dominant lithology in the Klang Valley Mass Rapid Transit line 1 project in Kuala Lumpur, Malaysia. A total 52 pressuremeter test and standard penetration test data pairs were obtained at depths ranging from 6 to 41.7 m within the Kenny Hill Formation (KHF) and the contact zone between the KHF and the limestone formation. This contact zone has shown distinct geological features with the characteristic of a lower N60 value underlying stiff strata. According to the EM/Eur ratio, the maximum value of 7 indicated that this zone is unpredicted in initial and unload–reload stiffness compared to the non-contact zone (the KHF only), with a maximum ratio of 3. Therefore, separate correlations were established to distinguish these zones. Strong correlations between N60 and EM were identified by splitting these zones. The proposed correlation was then compared with the previous research.

Determination of Soil Bearing Capacity from Spectral Analysis of Surface Wave Test, Standard Penetration Test and Mackintosh Probe Test

Spectral Analysis of Surface Wave (SASW) method is one of soil investigation methods which promotes cost-effective and less time-consuming procedures, apart form of its non-destructive nature. This study aims to determine the soil ultimate bearing capacity obtained from the SASW method by using Ali Keceli’s equation for sandy silt soil. The finding in terms of bearing capacity is then compared to the Standard Penetration Test (SPT) and Mackintosh Probe (MP) results. All the tests were conducted at seven different locations. It is found that there is no 1:1 relationship between the bearing capacity obtained from SPT and SASW although the pattern of the trendline is similar. However, the pattern of the trendline captured is not as similar as SPT for MP and SASW. The coefficient of determination (R2) between SPT and SASW varies from 0.74 to 0.95 and the R2 between the MP and SASW varies from 0.43 to 0.77. The overall R2 found for SPT and SASW is 0.87 and 0.74 for MP and SASW in all locations. For the comparison with SPT and MP, SASW is well-correlated with SPT and moderately with MP. From this study, it can be concluded that SASW has the potential to determine the ultimate bearing capacity of soil as an alternative to SPT and MP tests.

Effect of Irrigation Water Containing Iodine on Plant Physiological Processes and Elemental Concentrations of Cabbage (Brassica oleracea L. var. capitata L.) and Tomato (Solanum lycopersicum L.) Cultivated in Different Soils

Iodine uptake and translocation was studied in cabbage and tomato cultivated on different soil types (sand, sandy silt, silt) by applying irrigation water containing iodine at concentrations of 0.1 and 0.5 mg/L. Iodine treatment at the concentrations applied did not significantly influence the photosynthetic efficiency and chlorophyll concentration of cabbage and tomato leaves. The growth of cabbage leaves cultivated on sand and sandy silt soil with iodine treatment was slightly stimulated, while, on silt soil, it remained unchanged; for tomato plant parts, independent of the soil-type, the dry mass values remained constant. It can be concluded that iodine treatment had no negative effect on the physiological characteristic of cabbage and tomato plants. Applying 0.5 mg/L in the irrigation water, the highest biofortification with iodine was achieved in plants cultivated in sandy soil and the iodine concentration calculated in the dry matter amounted to 10 and 3.6 mg/kg in the leaves and fruits of cabbage and tomato, respectively. Considering the iodine and moisture content of cabbage leaves and tomato fruits, the consumption of 100 g of fresh vegetable would cover about 80% and 15% of the recommended iodine intake, respectively. The presence of iodine resulted in a reduction in Fe and P concentrations in tomato fruits independent of the soil-type; however, the concentration of Mg, Cu, Mn, Zn, and B remained practically unchanged. However, for cabbage, no similar trend for Fe and P was observed.

Laboratory Characterization of a Compacted–Unsaturated Silty Sand with Special Attention to Dynamic Behavior

The dynamic properties of compacted non-cohesive soils are desired not only because of the risk of natural sources of dynamic excitations such as earthquakes, but mostly because of the anthropogenic impact of machines that are working on such soils. These soils are often unsaturated, which positively affects the soil’s mechanical properties. The information about the values of these parameters is highly desirable for engineers. In this article, we performed a series of tests, including oedometric tests, resonant column tests, bender element tests, and unsaturated triaxial tests, to evaluate those characteristic parameters. The results showed that sandy silt soil has a typical reaction to dynamic loading in terms of shear modulus degradation and the damping ratio curves’ characteristics, which can be modeled by using empirical equations. We found that the compaction procedure caused an over-consolidation state dependent on the moisture content during compaction effort. The article analyzed the soil properties that impact the maximum shear modulus G0 value. Those properties were suction s, confining pressure σ3, and compaction degree represented by the void ratio function f(e).

Quantitative evaluation of pore characteristics of sodic soils reclaimed by flue gas desulphurization gypsum using X‐ray computed tomography

AbstractFlue gas desulphurization (FGD) gypsum can effectively remediate sodic soils through improving two‐dimensional/three‐dimensional (3D) soil pore characteristics, especially vertical macroporosity. Understanding the response pattern of pore characteristics of sodic soils with different textures to FGD gypsum reclamation measures is critical to formulating appropriate improvement strategies for addressing growing challenges of land degradation. The objectives of this study were (a) to quantify the effect of FGD gypsum on two‐dimensional/three‐dimensional pore characteristics of amended sodic soils using X‐ray computed tomography (CT); and (b) to investigate the response pattern of different sodic soils to reclamation measures. Three types of intact sodic soils (sandy loam, silty loam, and silt soil) were collected from different sodic fields in north China for X‐ray CT image scan, and soil pore characteristic parameters (including porosity, pore network density, pore length density, and tortuosity) were measured. The results indicate that the high proportion of horizontal pores and lower pore length density are typical features in the sodic soils investigated. The responses of three sodic soils to reclamation measures demonstrate obvious variations that the 3D macroporosity of silt sodic soils was significantly increased (p < .05) by 53.7%, showing more sensitive and better effect than that of sandy loam (52.9%) and silty loam (20%) sodic soils, in which the reclamation improved the vertical macroporosity of silt sodic soil by 164.6%. It is speculated that the higher clay and silt contents in the silt sodic soils and their interaction with gypsum contribute to the expansion of pore size, and the formed macropore promotes the vertical migration of clay and silt particles to further increase the vertical macroporosity. In addition, FGD gypsum is beneficial for the formation of new pores in silt loam soils. The findings of this study confirm the feasibility of quantifying pore characteristics of sodic soils with the help of X‐ray CT images and suggest that it is necessary to adopt specific reclamation strategies for different degraded sodic soils.

Development of Practical Correlations Between Cone Penetration Resistance and SPT Values for Various Types of Soils

A suite of relationships has been developed between cone penetration resistance (qc) and SPT values of clayey and sandy soils. The major difference between these relationships and those of previous studies lies in the range of data and variety of soils. Most studies with the same scope of research since 1959 have been considered herein, and their practical data have been collected. Then, by means of statistical analyses and data refinement, a database was provided for diverse types of soils (including silty sand, clayey, sandy and sandy silt soils). Accordingly, for each soil type, the data were classified as either regression or test data. The regression data were applied to develop the correlations between qc and SPT value (N60). The test data were employed to examine accuracy of the correlation compared to the available relationships for the same soil type. The results indicate that the proposed relationships between qc and N60 for silty sand, sandy and sandy silt soils are simple with RMSE values equal to 0.078, 7.012 and 7.498, respectively, whereas in the case of clay, the relationship becomes more complex (accuracy of 0.248). Based on the results derived herein, it can be concluded that all relationships proposed in this study are of greater accuracy compared to the previous relations.