Sandy Silty Soils Research Articles

Amelioration of fat clay treated with CNS and cohesionless soils

The present study evaluates the amelioration of fat clay by blending it with cohesive non-swelling soil (CNS) and cohesionless silty sandy soil (Kassu). The fat clay sample with a liquid limit (LL) of 50 and a plasticity index (PI) of 26 was collected from Narowal, while CNS and Kassu samples were procured from Lahore's outskirts. Geotechnical tests on the virgin soil indicated its unsuitability for construction. Laboratory tests, including modified Proctor compaction, unconfined compression, California bearing ratio (CBR), and one-dimensional consolidation, were performed on samples blended with 0–35% CNS or Kassu in 5% intervals. The LL and PI of fat clay decreased significantly with the addition of 35% CNS (LL: 50–32%, PI: 24 to 13) and Kassu (LL: 50–29%, PI: 24–12). The CBR value increased from 4 to 7%, making the blended soil suitable for subgrade use. Unconfined compression tests showed a strength increase from 102 to 185 kPa with 35% CNS and up to 140 kPa with 25% Kassu. Compaction tests revealed improved maximum dry unit weight and reduced optimum moisture content. Swell potential decreased from 4 to 1.2 and 0.26% with CNS and Kassu additions. Regression models predict swell pressure and ultimate swell potential. The study concludes that blending fat clay with CNS and Kassu significantly improves its geotechnical properties, with CNS being more effective in controlling swell characteristics.

Beneficial Use of Water Treatment Sludge with Stabilizers for Application in Road Pavements

Water treatment sludge (WTS) is the residue produced during water treatment processes for public use. Exploring the reintroduction of these wastes into the production chain to generate new, value-added materials presents a current challenge. This could promote their reuse and reduce the negative environmental impacts associated with their disposal. This study assessed the technical feasibility of using aluminum-based WTS to partially replace silty sand soil in mixtures that include two stabilizers (hydrated lime and Portland cement), potentially for use in road pavements. After conducting a thorough physical, chemical, and geotechnical characterization of both the soil and the sludge, bench-scale experiments were carried out to test the mixtures’ resistance, with WTS proportions of 5%, 8%, 10%, 15%, and 20%, stabilized with either lime or cement. The findings confirm that WTS does not contain potentially toxic elements, according to Brazilian standards, and all tested composites appear suitable for paving. However, the mechanical resistance of the soil–sludge–cement mixtures decreases as the WTS content increases, with an optimum California bearing ratio (CBR) of 41.50% achieved at a 5% WTS addition. Meanwhile, incorporating 15% WTS into soil–sludge–lime mixtures resulted in the highest CBR value of 21.25% for this type of mixture. It is concluded that incorporating stabilizers into soil–WTPS mixtures for road construction allows for an increased percentage of WTPS in silty-sandy soils. Further studies are recommended with different soil types and the addition of fibers to the mixes, to assess the long-term performance of the structure, along with economic and environmental analyses.

Numerical study on local scour characteristics around submarine pipelines in the Yellow River Delta silty sandy soil under waves and currents

AbstractDue to their high reliability and cost‐efficiency, submarine pipelines are widely used in offshore oil and gas resource engineering. Due to the interaction of waves, currents, seabed, and pipeline structures, the soil around submarine pipelines is prone to local scour, severely affecting their operational safety. With the Yellow River Delta as the research area and based on the renormalized group (RNG) k‐ε turbulence model and Stokes fifth‐order wave theory, this study solves the Navier–Stokes (N–S) equation using the finite difference method. The volume of fluid (VOF) method is used to describe the fluid‐free surface, and a three‐dimensional numerical model of currents and waves–submarine pipeline–silty sandy seabed is established. The rationality of the numerical model is verified using a self‐built waveflow flume. On this basis, in this study, the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field, shear stress, and turbulence intensity is analyzed. The results indicate that (1) local scour around submarine pipelines can be divided into three stages: rapid scour, slow scour, and stable scour. The maximum scour depth occurs directly below the pipeline, and the shape of the scour pits is asymmetric. (2) As the water depth decreases and the pipeline suspension height increases, the scour becomes more intense. (3) When currents go through a pipeline, a clear stagnation point is formed in front of the pipeline, and the flow velocity is positively correlated with the depth of scour. This study can provide a valuable reference for the protection of submarine pipelines in this area.

Zinc Fertilizer Applications to Ocimum basilicum L. under Water Stress: Changes in the Total Phenolic and Flavonoid Content, Essential Oil Compounds and Morphological Properties

Water stress poses a significant challenge for plant growth and productivity, impacting both yield and quality. With the ongoing changes in global climate, mitigating the adverse effects of water deficiency on plants has become crucial. In this study, the focus is on enhancing the tolerance of Ocimum basilicum L., a plant highly susceptible to water stress. To achieve this, in this study examined the effects of zinc fertilizer supplementation at varying rates (2.5 - 5 and 10 mg/kg) on O. basilicum grown in silty sandy soil and subjected to water stress conditions. Several parameters, including mineral uptake, morphological characteristics, total phenol and flavonoid contents, and essential oil compounds, were evaluated in sweet basil. The results revealed that water stress had a detrimental impact on the morphological properties and secondary metabolites analysed. Estragole emerged as the main compound in the essential oil analysis, with the highest concentration (69.37%) observed in the group treated with 10 mg/kg of zinc fertilizer. Conversely, the lowest concentration (66.14%) was recorded in the water-stressed group without fertilizer. Notably, the application of zinc fertilizer at concentrations of 5 and 10 mg/kg significantly ameliorated the negative effects induced by water stress. Furthermore, zinc exhibited diverse mechanisms of action concerning the uptake of other nutrients from the soil.

Pore Characterization of Sandy Silty Soil in Metro Surrounding Rock: A Synchrotron Small-Angle X-ray Scattering Experiment

Pore Characterization of Sandy Silty Soil in Metro Surrounding Rock: A Synchrotron Small-Angle X-ray Scattering Experiment

Attenuation of erythromycin-laden waste water using the constructed wetland technique

Erythromycin (ERY) is environmentally resilient because of its aromatic nature, which hinders degradation. In the present study, silty–sandy soil, with a saturated hydraulic conductivity (K) value of 1.66 × 10−7 m/s, was studied for its potential to remove aqueous ERY using a laboratory-scale constructed wetland. With a dose of 10 g/l, a concentration of 25 mg/l and a contact time of 30 min, the maximum adsorption reached 89.79 ± 1.5%, as found from batch experiments. The Freundlich isotherm (R 2 = 0.983, n = 0.575, K f = 0.04 mg/g) was the best fitting among different user models. In the kinetic study, the pseudo-second-order model (q e = 1.297 mg/g, K 2 = 0.182 g/(mg min)) had the best fit with experimental data. A one-dimensional vertical column study exhibited an exhaustion time of 2.7 days for a 40 mm deep soil bed to remove ERY. A laboratory-scale constructed wetland model composed of silty–sandy soil showed a reduction of ERY of 92.44%. Finally, the results were validated with the CW2D wetland model of the Hydrus software, which corroborated the experimental results. The outcome exhorts that constructed wetlands with silty–sandy soil may be an effective technique for the reduction of ERY present in waste water, which has profound importance from a social health perspective.

Efficacy Evaluation of Silty-Sandy Soil and Chrysopogon zizanioides to Attenuate Doxycycline from Wastewater in a Constructed Wetland System

Efficacy Evaluation of Silty-Sandy Soil and <i>Chrysopogon zizanioides</i> to Attenuate Doxycycline from Wastewater in a Constructed Wetland System

A data-driven method to model stress-strain behaviour of frozen soil considering uncertainty

Various experiments and computational methods have been conducted to describe the mechanical behaviours of frozen soils. However, due to high nonlinearity and uncertainty of responses, modelling the stress-strain behaviours of frozen soils remains challenging. Accordingly, we first propose a novel data-driven method based on Long Short-Term Memory (LSTM) to model the mechanical responses of frozen soil. A compiled database on the stress-strain of a frozen silty sandy soil is employed to feed into the LSTM model, where the mechanical behaviours under various temperatures and confining pressures are measured through triaxial tests. Subsequently, uncertainty of the stress-strain relations (i.e., deviatoric stress and volumetric strain to axial strain) is investigated and considered in LSTM-based modelling with Monte Carlo dropout (LSTM-MCD). Results demonstrate that the LSTM model without uncertainty can capture the stress-strain responses of the frozen soil with considerable predictive accuracy. Uncertainty analysis from LSTM-MCD reveals that the model with uncertainty can be applied to evaluate the mechanical responses of frozen soil with 95% confidence intervals. This study sheds light on the advantage of the data-driven model with uncertainty in predicting mechanical behaviours of frozen soils and provides references for permafrost construction.

Assessing the Effect of Particle Size Distribution on Permeability of Silty-Sandy Soils

Assessing the Effect of Particle Size Distribution on Permeability of Silty-Sandy Soils

The relationship between productivity and some drought tolerance indicators for several cultivars of bread wheat

The research was conducted in Tartous Governorate during the two agricultural seasons (2018–2019 and 2019–2020) under control conditions, the aim of the research is to study the relationship between the productivity of five promising strains of bread wheat (‘ACSAD 1256’, ‘Douma 58847’, ‘Douma 58585’, ‘Douma 64453’, ‘ACSAD 1149’) and two cultivars (‘Douma 2’ and ‘Douma 4’) and some quantitative indicators of drought: stress tolerance index ( STI), mean of productivity ( MP), modified stress tolerance index ( MSTI), and relative yield ( RY). Cultivation was carried out in pots filled with light sandy silty soil, and three treatments of 70, 50, and 30% of the field capacity were applied in addition to the control and with three replications for each treatment. The strains ‘Douma 58585’ and ‘Douma 58847’ gave high yield values for grain in the two agricultural seasons. It was also found that there were significant differences between the two seasons in yield between the control and drought stress factors and drought tolerance indicators, such as stress tolerance index, modified stress tolerance index ( MSTI), mean of productivity ( MP), and relative yield ( RY). On the other hand, a positive and strong relationship was found between STI, MSTI, and MP in both treatments and both seasons. The research concluded that the best indicators, which were related to the productivity, whether in the control or transactions and in the two growing seasons together, are STI and MP, which are promising indicators in the classification of stress-tolerant cultivars or strains.

Investigation of the Liquefaction Potential of Coal Ash Due to Seismic Loading

Abstract Coal ash is a geomaterial with a metastable structure. This type of geomaterial is significantly susceptible to liquefaction as a result of seismic loads. An investigation of ash that is susceptible to liquefaction due to a seismic load can use the CPT penetration test. This method of investigating liquefaction was developed based on numerous penetration tests of sandy or silty–sandy soils and was developed at the Workshop on the Evaluation of Soil Liquefaction Resistance, NCEER, Salk Lake City, Utah, USA, 1996. In the present article, the results of the CPT penetration test conducted at the Rosina ash tailings pond in Žilina in Slovakia, are analyzed using the NCEER methodology. The safety factor for ash liquefaction was expressed based on the penetration resistance values measured in the CPT tests using the ‘LiquefyPro’ software. The safety factor in the liquefaction of the ash sediment was expressed by changing the level of seeping water in the body of the tailings pond, the unit weight of coal ash, and the seismic acceleration.

Case study in the Northern Cape (Loopeng area), South Africa, confirming occurrence of a collapsible sand soil structure in transported soils

Abstract Testing was performed on transported soils belonging to recently deposited sandy-silty soil deposits occurring in and around Loopeng Village, Northern Cape Province, South Africa, in order to determine the occurrence and order of magnitude of a collapsible sand soil structure. Various empirical geotechnical characteristics including: in situ soil profile structure description, particle grading curve and clay content, soil classification, soil density and void ratio were compared to collapse potential values determined with oedometer testing, in order to judge the success with which the empirical characteristics can be utilised to predict the occurrence of a collapsible soil structure. From the results it is clear that a collapsible sand structure exists in the transported soils (both aeolian and fine alluvial) and that the empirical descriptors mostly correctly indicate the occurrence of the particular soil structure when compared to existing studies on collapsible sands. The one descriptor which reflects a relatively poor prediction of a collapsible soil structure, namely the in situ soil profile structure description, is considered to be a poor indicator due to erroneous or poor in situ soil structure observations. These poor observations result from unfavourable local conditions namely dry, dusty soil conditions and very brief intact standup time of test pit side walls.

Efficacy Assessment of Silty–Sandy Soil as Bed Material in Constructed Wetland to Treat Naphthalene-Laden Wastewater: Physical and Numerical Modeling

Naphthalene is a common polycyclic aromatic hydrocarbon that is widely present in aquatic environments and has colossal negative health effects on living beings. Thus, the removal of naphthalene from wastewater using sustainable, low-cost geomaterials and novel technologies is of prime importance. In this study, the efficacy of a locally available silty–sandy soil in attenuating aqueous naphthalene was assessed using a laboratory-scale constructed wetland. The hydraulic conductivity of the soil was found to be 1.66 × 10−5 cm/s. Batch adsorption data showed that the Langmuir and pseudo-second-order models were the best fitting isotherm and kinetics models, with coefficient of determination values of 0.98 and 0.99, respectively. A one-dimensional vertical-column study using the tested soil on naphthalene showed that the exhaustion time of a 40-mm-deep soil bed was about 1.6 days. A laboratory-scale rectangular-tank test conducted using that soil, with the same test numerically modeled using HYDRUS solute-transport software, revealed that 90% of the initial concentration of naphthalene would reach the outlet in 102 days. The wetland constructed using the selected soil indicated a reduction in the naphthalene concentration of up to 92.8%, which corroborated the results from the CW2D HYDRUS module.

Development and validation of a model for soil wetting geometry under Moistube Irrigation

We developed an empirical soil wetting geometry model for silty clay loam and coarse sand soils under a semi-permeable porous wall line source Moistube Irrigation (MTI) lateral irrigation. The model was developed to simulate vertical and lateral soil water movement using the Buckingham pi (π) theorem. This study was premised on a hypothesis that soil hydraulic properties influence soil water movement under MTI. Two independent, but similar experiments, were conducted to calibrate and validate the model using MTI lateral placed at a depth of 0.2 m below the soil surface in a soil bin with a continuous water supply (150 kPa). Soil water content was measured every 5 min for 100 h using MPS-2 sensors. Model calibration showed that soil texture influenced water movement (p < 0.05) and showed a good fit for wetted widths and depths for both soils (nRMSE = 0.5–10%; NSE ge 0.50; and d-index ge 0.50. The percentage bias left( {PBIAS} right) statistic revealed that the models’ under-estimated wetted depth after 24 h by 21.9% and 3.9% for silty clay loam and sandy soil, respectively. Sensitivity analysis revealed agreeable models’ performance values. This implies the model's applicability for estimating wetted distances for an MTI lateral placed at 0.2 m and MTI operating pressure of 150 kPa. We concluded that the models are prescriptive and should be used to estimate wetting geometries for conditions under which they were developed. Further experimentation under varying scenarios for which MTI would be used, including field conditions, is needed to further validate the model and establish robustness. MTI wetting geometry informs placement depth for optimal irrigation water usage.

Optimum Bacteria Suspension Volume for Stabilizing Silty Sand Soils by Sporosarcina pasteurii Bacteria

Recently, the bio-mediated soil improvement techniques have gained an increasing attention. In this method, the bacteria was cultivated aerobically in the laboratory and added to the soil with reactant solutions such as urea and calcium chloride. Most of the existing studies are on sandy soils and a few researches have done on silty sandy soils. However, most soils in nature are compounds of fine-grained and coarse-grained soils. In fine-grained soils, silt does not have very good resistance due to the lack of adhesion between its particles. Hence, in this study Sporosarcina pasteurii bacterium was aerobically cultivated for stabilizing the sand with different percentages of silt to determine the optimum bacteria suspension volume. After some bacterial tests such as measuring bacterial growth, standard plate count, gram staining, pH determination, growth without urea, and urease test, geo-technical tests like soil sieve, compaction, and Atterberg limits were also done. Standard plate count was estimated 2.5*108 through serial dilution plating and culture media pH was determined 8.64 from different samples. Moreover, to achieve the best results, different sampling methods were compared. As the calcium carbonate creates a network of calcified bridges of calcite between sand grains, an electron microscope was used for scanning the surface with a focused beam of electrons. Results of triaxial tests showed that by adding optimum bacteria suspension volume, the maximum strength for samples with 0, 10, 20, 30 and 40% of silt was improved from 700, 900, 750, 600 and550 to 1100, 1400, 1550, 1600, and 1500 kPa, respectively.

Microbial richness in sandy-silty soil Tunisia and its role in arid zone fertilization

Arid zone are stressful environments, typified by alkaline soils low in organic matter, with biologically limiting extremes in water availability, temperature, and UV radiation. This study aims to analyze the microbial diversity of forest soil and its evolution considering climate change in a typical Mediterranean forest of cork oak (Quercus suber L.) and its importance in arid soil fertilization. The investigation was conducted in forest at north-western Tunisia. The study of the quality of the forest soil was based on physicochemical (pH, C, N, EC...) and microbiological (fungi and bacteria) analyses. A collection of strains has been isolated and identified morphologically (form, gram ...) and biochemically (enzymatic activity: catalase, oxidase ...). According to the results obtained, the forest soil has a pH of about 5.03 ± 0.2, C/N ratio 39.82±1.02. The count and fungi, non-filamentous and non-filamentous bacteria on solid soil show a great diversity that confers the fertility of the soil. An important number of strains of actinomycetes (45 isolates) and non-filamentous bacteria (82 isolates) showing distinctive morphological characteristics. The isolates enzymatic activity showed an important value. These obtained results give an idea on the microbe diversity that can be used in the field of bio-fertilization of poor microbial structure soils as the arid zones and oasis system.

CPT-based analysis of structured soil characteristics and liquefaction failure of the Yellow River Subaquatic Delta

The classification of seabed soil in the Yellow River Subaquatic Delta can be obtained more accurately by cone penetration test (CPT). The Soil behavior type index (Ic), over-consolidation ratio (OCR), sensitivity (St) and the relationship between them were clarified. The cyclic stress ratio (CSR) of seabed soil in the Yellow River Delta was calculated based on the wave elements in the 5-year recurrence period, and the cyclic resistance ratio (CRR) was further obtained by calculating the shear wave velocity. The liquefaction analysis was carried out. The analysis of the structure and liquefaction of the seabed soil in the Yellow River Delta is mainly from the following aspects: the seabed soil in the Yellow River Delta is mainly composed of silty soil, sandy soil and cohesive soil. Most areas are in the state of over-consolidation, with the OCR between 20 and 60, and the over-consolidation ratio decreases with the increase of offshore distance. It belongs to the highly sensitive soil layer with poor structure, and the sensitivity is linearly correlated with the over-consolidation ratio. The degree of liquefaction of soil layer is higher than that of offshore soil layer, and the liquefaction of sensitive fine-grained soil layer occurs easily.

New species Semitobrilus filipjevi sp. n. from Laos and taxonomic structure of the genus Semitobrilus Tsalolikhin, 1981 (Nematoda: Tobrilida, Tobrilidae, Neotobrilinae)

A description of the new species Semitobrilus filipjevi sp. n. from Laos is given. The new species differs from the other species of the genus by its long head setae. The new species differs from S. pellucidus in the length of the head setae (more than 50% of the head width) and the presence of crystalloids in the body cavity. The new species was discovered in the silty-sandy soil from a forest pond in southern Laos. An identification key of the species and a refined diagnosis of the genus Semitobrilus is provided. The species characters and species composition of the genus Semitobrilus are discussed. It is proposed to synonymize the species S. closlongicaudatus (Gagarin, 1971) with the species S. longicaudatus (Hofmaenner, 1913). The species S. gagarini (Ebsary, 1982) is transferred to the category sp. inq. The length of the head setae is the main character of the species. The presence of crystalloids in the body cavity is an unreliable character. Errors in the descriptions of S. ebsaryi, S. gagarini, and S. pellucidus are discussed. The work used the materials from the collection of the Zoological Institute of the Russian Academy of Sciences, including the original slides by I. N. Filipjev.

Assessing the Dynamic Behaviour of Midrise Frame Structures Sitting on Silty Sandy Soil

Background:Midrise 5 to 15 storeys frame structures sitting on soft soils are susceptible to damage induced by seismic events. The level of damage is related to the interaction between the structure, foundation and soil called Soil Structure Interaction (SSI). If the level of ground acceleration is low, the wave gets amplified putting the structure at risk of collapse.Objective and Methods:Concerns about SSI have motivated several researchers to investigate the seismic behaviour of structures rested on cohesive and cohesionless soils. The objective of the work presented in this paper is to evaluate the effects of several parameters on the seismic soil structure interaction behaviour of midrise structures sitting on silty sandy soil. Using ABAQUS, reliable 3D models of 5 to 15 storeys midrise concrete frame structures rested on raft foundation were built. The effects of the structure’s number of storeys, raft size and thickness were explored for different column sizes. Fixed-based structures which capture the model adopted in seismic codes and flexible-based structures were hit at the bottom by El-Centro (1940) and Northridge (1994) earthquakes.Results and Conclusion:The results, presented in terms of storey lateral deflection, inter-storey drift, shear force, foundation rocking and response spectrum showed the important contribution of SSI effects on the behaviour of the midrise structures. The model analyses indicated that column size strongly affects the behaviour of flexible structures. LetNbe the structure number of storeys andCthe column size. The results showed that in terms of storey lateral deflection and levelling shear force, for column sizes C 0.5 X 0.5 m, SSI was detrimental to structures with 10 ≤N≤ 15 and beneficial to structures with 5 ≤N&lt;10. Increasing the column size to C 0.5 X 1 m showed that SSI became detrimental for structures with 10 &lt;N≤ 15 under El-Centro (1940) and for structures with 7≤N≤ 15 under Northridge (1994), and beneficial for structures with 5 ≤N≤ 10 under El-Centro (1940) and for structures with 5 ≤N&lt; 7 under Northridge (1994). The FE results showed that even though base shear increased with raft size, lateral deflections were amplified for C 0.5 X 0.5 m S15 structures and attenuated for C 0.5 X 1 m S15 structures. However, the seismic response of S15 structures was slightly affected by the variation in raft thickness under both column sizes. Finally, the paper includes a discussion and evaluation of the contribution of inertial and kinematic effects, including soil types used on the simulated numerical models’ seismic responses.

Monotonic and dynamic properties of riverbed sand and hill-slope soils of seismically active North-east India for ground engineering applications

The stress–strain characteristics of soil under monotonic loading conditions and the dynamic properties of soils under cyclic loading are necessary for foundation engineering, ground response analysis and soil structure interaction studies. In the absence of site/region-specific properties, it is a common practice to use representative parameters based on the index properties of soil and available standard correlations. Such correlations might be inadequate for regional soils of varying index properties. Based on monotonic and cyclic triaxial tests, this study reports the monotonic and dynamic soil properties of the prevalent soils from the northeastern region of India, namely the cohesionless, cohesive and silty-sandy soils. It is observed that monotonic response of cohesionless soil is mostly influenced by the initial relative density, while the response of cohesive and silty-sands are primarily influenced by the effective confining pressure and degree of saturation. The cyclic triaxial tests revealed that, irrespective of the soil type, the strain-dependent modulus reduction and especially the damping ratio curves are noticeably different from available standards. The study highlights the importance of identifying the site/region specific soil properties for their usage in GRA and SSI applications.