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Several biopolymer applications in geotechnical engineering have been adopted in recent years, notably dust control, soil strengthening, and erosion control. Although biopolymer soil treatment approaches can assure engineering efficiency while satisfying environmental protection standards, this technology requires more validation regarding site adaptability, durability, and economic feasibility. The influence of biopolymers on soil behavior is discussed within geotechnical engineering applications and practices, including soil consistency limits, strength and deformation parameters, hydraulic conductivity, soil-water properties, and erosion prevention. Laboratory studies were performed to confirm the behavior of the treated soil, including Atterberg limits, proctor, and direct shear tests utilizing two types of biopolymers: guar gum and xanthan gum. [ABSTRACT FROM AUTHOR]

This research study investigates how incorporating soft nanoparticles affect the wear behavior and the characteristics of the materials in three-body mixed lubrication conditions. A disk-on-block tribometer was used to revealed a positive correlation between plasticity index and wear rates, indicating that increased plastic deformation leads to higher wear. The size and concentration of copper oxide (CuO) nanoparticles significantly influenced wear behavior. The study found that for block materials with a hardness of 27 HRC and 43 HRC paired with a disk of 58 HRC, increasing nanoparticle concentration and using larger nanoparticles relative to surface roughness (larger nanoparticle size and surface roughness ratio) resulted in reduced wear. The larger nanoparticles can more effectively fill the gaps on the smoother surface, increasing contact area and minimizing plastic deformation during sliding, especially when the contact is more elastic. However, when the counteracting block material is significantly harder than the disk, the effect of nanoparticles might be reversed, potentially leading to increased wear. These findings suggest a complex interplay between material properties, nanoparticle characteristics, and wear resistance, influenced by the relative hardness of contacting surfaces. This research offers valuable insight for developing materials with improved wear performance in applications involving sliding friction in third-body contact.

Salinity and sodicity greatly influences ongoing physical processes in soils. Organic matter may rehabilitate physical and mechanical properties of soils. Vermicompost as an amendment influences moisture-related parameters including consistency (plastic – PL and liquid limit – LL) and compaction. This study was conducted on soils (sandy-clay-loam) treated with different salinity levels (0.58 (control – irrigation water quality, tap water), 4 and 8 dS m−1) to investigate the effects of different vermicompost doses (0% (control), 2.5% and 5% w/w) on soil consistency limits and compaction. The pot experiment was carried out in a total of 27 pots, i.e. 3 (vermicompost doses) x 3 (salinity levels) x 3 (number of replicates). For Proctor compaction properties, maximum dry bulk density (MDD) reduced and optimum water contents (OWC) increased with increasing vermicompost doses under different salinity levels (p <.01). Increasing vermicompost doses under the lowest salinity level (0.58 dS m−1) yielded increasing optimum water contents for control (LL = 35.93% and PL = 25.85%). Optimum water contents were determined as 42.19% (LL) and 29.93% (PL) for 2.5% vermicompost dose and as 47.33% (LL) and 36.01% (PL) for 5% vermicompost dose under the lowest salinity level. LL, PL, OWC and MDD were significantly affected by vermicompost x salinity interactions. The highest maximum dry bulk density (1.92 g cm3) and the lowest optimum water contents (13.50%) were obtained from 0% vermicompost under the 8 dS m−1 NaCl level. Mean weight diameter (MWD) values ranged from 0.690 mm for 0% VC treatment under high Na salt level (8 dS m−1 NaCl) to 0.821 mm for 5% VC treatment under lowest Na salt level (0.58 dS m−1 NaCl). The correlations between aggregate stability (particle size group 1–2 mm) and optimum water content were 0.647*, 0.587* and 0.598* as compared to correlations of −0.512*, −0.470*, and −0.617** between aggregate stability (particle size group 1–2 mm) and maximum dry bulk density for the 0, 4 and 8 dS m−1 NaCl levels, respectively. MWD was positively correlated with OWC (0.386*) and negatively correlated with MDD (−0.385*). The greatest (2.39%) and the lowest (0.32%) soil organic matter values were respectively observed in 5% VC under the lowest salinity level (0.58 dS m−1) and 0% VC with at high Na salt level (8 dS m−1 NaCl). It was concluded that vermicompost reduced compaction-induced damage in soils. [ABSTRACT FROM AUTHOR]

Liquid and plastic limits are important parameters of soil hydraulic properties and are important in the research of collapsing gullies. To investigate the specific ion effects on the liquid and plastic limits of collapsing gullies, soil samples from three soil layers in a soil profile（red soil layer, sandy soil layer, and detritus layer) of a stable collapsing gully located in Hetian Town of Changting County, Fujian Province, were collected and exchanged with three kinds of electrolyte solutions（Li+, Na+, and K+) to analyze the liquid and plastic limits. The main results were as follows: the red soil layer had the highest plastic limit, liquid limit, and plasticity index, followed by the sandy soil and detritus layers（P＜0.05). Correlation analysis showed that the clay content, organic matter content, cation exchange capacity, and kaolinite content were positively correlated with the plastic and liquid limits（P＜0.05). Clay and organic matter contents were significantly positively correlated with the plastic limit. The plastic limit, liquid limit, and plasticity index of the red soil layer exchanged with K+ were 5.80%, 9.53%, and 12.99% higher than those exchanged with Li+, and 3.50%, 9.77%, and 15.86% higher than those exchanged with Na+, respectively. The plastic limit, liquid limit, and plasticity index of the sandy soil layer exchanged with K+ were 7.22%, 6.69%, and 6.83% higher than those exchanged with Li+, and 4.33%, 5.27%, and 7.32% higher than those exchanged with Na+, respectively. However, the liquid and plastic limits of the detritus layers did not differ significantly. The liquid and plastic limits of the red and sandy soil layers exchanged for K+ were significantly higher than those exchanged for Li+ and Na+. Therefore, compared with Li+ and Na+, K+ could increase the liquid and plastic limits of collapsing gullies. [ABSTRACT FROM AUTHOR]

Abstract Background Hyptis suaveolens (L.) Poit., native to the American tropics, is a pantropical annual plant and a major invasive species throughout India. It was anticipated that the availability of sunlight, coupled with its superior reproductive potential, persistent propagule bank, and dispersal ability, could lead to an increase in the growth and spread of this invader, thus potentially impeding herbaceous growth and diversity in non-native areas. Clarifying its ecological fitness and competitive performance will be useful to manage the spread of H. suaveolens in natural ecosystems that are facing a wide range of anthropogenic pressures. Methods The present study is a three-tier experiment. In the first tier, a field study was conducted to assess the patterns of H. suaveolens abundance and herbaceous species diversity in response to light availability (sun, 842–1072 µmol m–2 s−1 and shade 253–341 µmol m– 2 s−1) in the tropical dry deciduous ecosystems in the Vindhyan highlands, India. Furthermore, the impact of H. suaveolens abundance on the resident native and non-native species abundance and diversity was also studied. In the second tier, a randomized common garden experiment was conducted to understand the trait fitness of H. suaveolens in sun (940 µmol m–2 s−1) and shade (300 µmol m–2 s−1) conditions. In the third tier, a plant growth chamber experiment with high-light (940 µmol m–2 s−1) and low-light (300 µmol m–2 s−1) treatments was done to learn how H. suaveolens partitions its biomass between aboveground and belowground plant parts. Results The field study indicated that the sunlit areas had a higher abundance of H. suaveolens and a lower diversity of resident herbaceous species than the shaded areas. The common garden experiment showed that sun-dwelling H. suaveolens individuals performed better in germinative, vegetative, eco-physiological, and reproductive traits than the shade-dwelling individuals. The growth chamber experiment exhibited that plants grown in high-light environment had greater seed germination, seedling recruitment, and aboveground biomass than those grown in low-light environment, whereas plants grown in low-light environment exhibited a higher root mass ratio than the high-light individuals. These results suggest that H. suaveolens individuals mask the understory vegetation owing to higher seedling recruitment, relative growth rate, photosynthetic performance, resource acquisition-allocation, and reproductive output in response to high-light conditions. Conclusions The study concludes that light significantly controls the invasive population dynamics of H. suaveolens in dry deciduous forests. In high-light areas, H. suaveolens populations dominate the forest understory with suboptimal shade tolerance. In shade environment, H. suaveolens maintains a persistent soil seed bank along with ‘Oskar individuals’ that become active in response to high-light availability. The modus operandi is a ‘sit and wait’ strategy. The current study provides insights on prioritizing areas for H. suaveolens management that will potentially reduce the risk of biological invasions on the native species diversity of tropical regions.

Background: Hyptis suaveolens (L.) Poit., native to the American tropics, is a pantropical annual plant and a major invasive species throughout India. It was anticipated that the availability of sunlight, coupled with its superior reproductive potential, persistent propagule bank, and dispersal ability, could lead to an increase in the growth and spread of this invader, thus potentially impeding herbaceous growth and diversity in non-native areas. Clarifying its ecological fitness and competitive performance will be useful to manage the spread of H. suaveolens in natural ecosystems that are facing a wide range of anthropogenic pressures. Methods: The present study is a three-tier experiment. In the first tier, a field study was conducted to assess the patterns of H. suaveolens abundance and herbaceous species diversity in response to light availability (sun, 842–1072 µmol m–2 s−1 and shade 253–341 µmol m–2 s−1) in the tropical dry deciduous ecosystems in the Vindhyan highlands, India. Furthermore, the impact of H. suaveolens abundance on the resident native and non-native species abundance and diversity was also studied. In the second tier, a randomized common garden experiment was conducted to understand the trait fitness of H. suaveolens in sun (940 µmol m–2 s−1) and shade (300 µmol m–2 s−1) conditions. In the third tier, a plant growth chamber experiment with high-light (940 µmol m–2 s−1) and low-light (300 µmol m–2 s−1) treatments was done to learn how H. suaveolens partitions its biomass between aboveground and belowground plant parts. Results: The field study indicated that the sunlit areas had a higher abundance of H. suaveolens and a lower diversity of resident herbaceous species than the shaded areas. The common garden experiment showed that sun-dwelling H. suaveolens individuals performed better in germinative, vegetative, eco-physiological, and reproductive traits than the shade-dwelling individuals. The growth chamber experiment exhibited that plants grown in high-light environment had greater seed germination, seedling recruitment, and aboveground biomass than those grown in low-light environment, whereas plants grown in low-light environment exhibited a higher root mass ratio than the high-light individuals. These results suggest that H. suaveolens individuals mask the understory vegetation owing to higher seedling recruitment, relative growth rate, photosynthetic performance, resource acquisition-allocation, and reproductive output in response to high-light conditions. Conclusions: The study concludes that light significantly controls the invasive population dynamics of H. suaveolens in dry deciduous forests. In high-light areas, H. suaveolens populations dominate the forest understory with suboptimal shade tolerance. In shade environment, H. suaveolens maintains a persistent soil seed bank along with 'Oskar individuals' that become active in response to high-light availability. The modus operandi is a 'sit and wait' strategy. The current study provides insights on prioritizing areas for H. suaveolens management that will potentially reduce the risk of biological invasions on the native species diversity of tropical regions. [ABSTRACT FROM AUTHOR]

This study delves into the necessity of surface treatment for pure nickel, with a primary focus on applying abrasive jet machining (AJM) in conjunction with a microcontact wear model to investigate the contact interface mechanisms involved in AJM. Experimental findings indicate that SiC particles primarily employ a cutting mechanism to remove asperity peaks on the workpiece surface. While this effectively removes these peaks, it may induce phenomena reminiscent of peen hardening and embedded hardening. Conversely, Al2O3 particles predominantly engage in a rolling extrusion mechanism, leading to noticeable hardening effects akin to peen hardening. The study utilizing microcontact theory derived a 90° erosion wear formula. The study demonstrates that SiC particles outperform Al2O3 particles. SiC particles significantly increase the curvature radius of surface peaks (ρ) and the real contact area (At) during equivalent grinding durations, substantially enhancing workpiece surface quality and service life. Furthermore, post-grinding, an expansion in the elastic deformation region at the particle-workpiece interface, attributed to workpiece surface hardening, mitigates wear, and stabilizes surface roughness. This comprehensive research thoroughly assesses the interfacial effects of different abrasives and grinding parameters, providing valuable insights for related fields. [ABSTRACT FROM AUTHOR]

This paper introduces a novel micro-elastic composite grinding pad for material removal. The study also developed a new grinding wear formula grounded in microcontact mechanics, which is crucial in examining the evolution of interface characteristics under optimal parameter combinations. The results showed that the material removal rate (MRR), reduction of roughness height (σ), and peak curvature radius (ρ) increase were the highest in the initial stage, followed by a slight increase in the real-contact area in the second stage. This research suggests that abrasive particles primarily detach from the elastic pad in the second stage. The plasticity index (ψ) decreases during grinding, which suggests a transition from an elastic-plastic mixed contact interface to a predominantly elastic contact interface. This shift in the interface mechanics explains the gradual reduction in wear at the grinding interface. Both the plasticity index and the MRR are consistent throughout the grinding process. However, the plasticity index is a more effective index of interface wear than the conventional H/E ratio because it considers the surface roughness's shape and size, which is essential in mild grinding operations. The findings of this study can be used to improve the design and performance of micro-elastic composite grinding pads and to optimize the grinding process for improved efficiency and sustainability. [ABSTRACT FROM AUTHOR]

This study aims to determine the capacity of surface soils, the loading layers of engineered structures with shallow foundations, to swell. For this, five samples were collected using a hand auger at a depth of 1.5–2 meters in the city of Al-Faw in Basra, Iraq. The swelling potential of the soils in the research area was calculated using the clay content, liquid limit, plasticity index, and shrinkage limit values, and the constituent minerals were identified using X-ray diffraction. According to the results of the Atterberg’s limit tests, the soil samples taken from the city of Al-Faw fall into one of three categories: clayey silt low plasticity (ML), clay high plasticity (CH), or silty clay low plasticity (CL). The liquid limit in soil samples ranges between 34-55%, and the plasticity index values range between 12 and 28%. Three samples are of medium swelling potential, while the third location has high swelling potential and the second location has low swelling potential, and the X-ray diffraction data demonstrate that Montmorillonite is the main dominant clay mineral, accounting for an average of 31.88%, followed by Kaolinite mineral, which accounts for an average of 28.984%, Illite, which accounts for an average of 19.5702%, Chlorite, which accounts for an average of 12.1864%, and Palegorskite, which accounts for an average of 7.3688%. [ABSTRACT FROM AUTHOR]

Plasticity index, Ip, is a relatable parameter for most geotechnical engineers, because Ip can be used to estimate other soil properties, such as internal friction angle, compression index, and low-strain shear modulus. Consequently, a method for estimating Ip directly from a piezocone penetration test (CPTU), which measures cone resistance, sleeve friction, and pore pressure would be useful for many practising geotechnical engineers. This technical note presents a method for estimating Ip profiles entirely from CPTU data. The new method has been calibrated using a case database of 258 complementary measurements taken, in natural soils, at 25 globally distributed marine sites. [ABSTRACT FROM AUTHOR]

Weak soils in marine environments present unique challenges for engineering endeavours due to its inherent characteristics and the dynamic nature of aquatic systems. In recent times, the use of nanomaterials has emerged as an effective method for strengthening such soft soils. The present study highlights the effect of nano-titanium dioxide on the strength, plasticity, and compressibility characteristics of marine soil treated with the optimal amount of lime (5%). The potential of nanoparticle in modifying the geotechnical behaviour was examined by adding 0.5%, 0.7%, 1%, and 1.2% of N-TiO2 per unit weight of dry soil. The unconfined compressive strength values of untreated, optimally lime-treated and optimally nano-treated soil specimens were 47 kPa, 467 kPa and 164 kPa, respectively. After 28 days curing period, the unconfined compressive strength of optimally lime-treated marine soil samples mixed with the optimal amount of 0.7% N-TiO2 showed a nine-fold increase to 491 kPa with respect to untreated soil. After the nanotreatment, the liquid limit reduced by 51% and the plasticity index lowered by 74%. This resulted in the improvement of the coefficient of consolidation from 0.001 to 0.004 cm2/s and a reduction in compression index value from 0.39 to 0.17. The microstructure of soil samples was examined using various techniques such as X-ray powder diffraction analysis, Field Emission Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, and Brunauer–Emmett–Teller surface area analysis. The experimental observations indicate that marine soil treatment using N-TiO2 is a promising technique to improve the geotechnical behaviour of marine soil. [ABSTRACT FROM AUTHOR]

The study assessed petroleum systems in the southern Bida Basin, Nigeria, focusing on the Cretaceous sediments. Reservoirs comprise Lokoja and Patti Formation sandstones, while shales, claystone, and siltstone serve as source rocks and stratigraphic traps/seals. Detailed studies delineating the key elements of the petroleum systems in the basin have not been conducted due to a lack of subsurface data. The goal of the current study was to use field observations, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and geochemical and geomechanical data to evaluate key components of petroleum systems in the southern Bida Basin. The results presented in this investigation are intended to attain specific objectives, especially those lacking in the basin's study sections. Petrophysical analysis revealed that the Lokoja Sandstone has porosity of 37%–39.5% and moderate permeability of 23.22–42.29 mD. The Patti Formation sandstone reservoirs exhibited high porosity (38%–42%) and moderate to good permeability (31.54–66.48 mD), suggesting good potential reservoirs. SEM results revealed intragranular pores and micro-fractures in the Patti Shale, whereas the sandstone reservoirs in the Lokoja and Patti formations displayed fractures, facilitating hydrocarbon migration. Quartz was the dominant mineral in the sandstone units of both formations. XRD analysis revealed that brittle and clay minerals influenced the microstructure of Patti Shale. Geochemical analysis indicated promising petroleum potential in the Patti Shale, with a total organic carbon (TOC) content of 1.87 wt%, free hydrocarbon from kerogen (S1) of 0.41 mg/g, hydrogen index (HI) of 0.75 mg HC/g TOC, and production index (PI) of 0.17. The Patti and Lokoja formations' shale, claystone, and siltstone exhibited sealing potential, with a plasticity index of 24–35 and coefficient permeability of 2.8 × 10−4- 3.6 × 10−4 cm/s. Field studies, XRD, geochemical data, and geomechanical index values have confirmed the key components of the petroleum system, which in turn facilitate hydrocarbon generation, migration, accumulation, and entrapment in the basin.

With global concerns on carbon emissions, there is increased need for various eco-friendly alternatives to conventional (cement and lime) additives used in ground improvement applications. This paper investigates the effect of three biopolymers—chitin, chitosan, and sodium carboxymethyl cellulose (NaCMC)—on the consistency limits of low plasticity organic silt soil. The theory of soil mechanics suggests that understanding the soil's plasticity nature is helpful in predicting strength and compressibility characteristics. The variation in the Casagrande liquid limit (LL), plastic limit (PL), plasticity index, and flow index of the soil are presented for 0.5–4% chitin and chitosan dosages, and 0.25–1% NaCMC dosage. For all three biopolymers, the consistency limits (more-so for LL than PL) increased with increasing dosage, with NaCMC addition producing a more dramatic effect compared to chitin and chitosan additions. The biopolymer additives formed 'bridge' connections between the soil particles, helping to improve strength properties. This bridging effect explains the significant increases in LL (being essentially a strength-based parameter) for biopolymer addition. A greater LL increase was observed for NaCMC addition since it is a gellable biopolymer with moisture retaining property. [ABSTRACT FROM AUTHOR]

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The northern coastal strip of Venezuela with a semiarid climate presents conditions for the development of extensive areas with the presence of expansive clays, and, this is the main pathology of its communication routes due to deformation in the surrounding civil works. This contribution characterizes the presence of expansive clays in northern Venezuela in 81 samples distributed in several states of the country. The study included the determination of geomechanical properties through field work and laboratory tests by Atterberg limits, consistency indices and expansion tests as well as the relationship between the indexes and information from edometer tests. The soil grain size is mainly fine (silts and clays), in the Anzoátegui state the average content of fine grains is 86%, while in Falcón and Miranda they are a little lower, 82% and 67%, respectively. In general, the plasticity index (PI) of these expansive clays is high, with an overall average of 23, although the region of Falcón state presented a moderate average (18). The correlations between the expansion pressure and the PI showed a high correlation. These results corroborate that the criterion used to evaluate the Expansion Potential of a clay soil based on the PI proposed by Chen (1988), is a fairly adequate criterion to be used in the study and identification of the expansive behavior of these types of soils. [ABSTRACT FROM AUTHOR]

The creep index plays an important role in calculating the long-term settlement of natural soft clays, so it is vital to determine the creep index quickly and accurately. However, the prediction accuracy of the existing creep index models is low. This study presents seven gene expression programming (GEP) models by using different combinations of the liquid limit wL, plasticity index Ip, void ratio e and clay content CI as input variables for the prediction of creep index. A total of 151 datasets were collected from the available literature for building and testing the GEP models. The proposed GEP models were compared with two machine learning (ML) models (i.e., back propagation neural network and random forest) and five conventional empirical models in terms of three statistical indicators. The research results showed that the prediction performances of the two proposed GEP models (i.e., with combinations C I - w L - e and C I - I p - w L - e as input, respectively) surpass those of the five conventional empirical models and two ML-based models, recommended for predicting the creep index of natural soft clays in engineering practice. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ni-based coatings are extensively used in industry for the surface properties enhancement and improving the system performance under different operating conditions. The resistance to wear and corrosion of the components is found to be improved when the substrate is coated with the coating powder. However, determining the wear rate and wear mechanism is very important and time-consuming process. The coating and counter material properties play important role in the wear rate and wear mechanism. The plasticity index in the dry sliding condition may be used as wear measuring indicator which is governed by the hardness of the coating, asperity radius and the reduced elasticity modulus. In this paper, the plasticity index for different combinations of tribopair (Coating and counter materials) is compared with the dry sliding wear rate obtained for respective pairs. The outcomes show that the specific wear rate obtained for the dry sliding wear can be directly related to the plasticity index. [ABSTRACT FROM AUTHOR]

Correlation analysis of physical and mechanical indexes of Shanghai soil was carried out. Using the support vector machine algorithm, the authors constructed a correlation analysis model of soil plasticity index, liquidity index and compressibility coefficient based on the soil indoor test data obtained from several engineering sites. Then the model parameters were optimized by combining the error indexes. Comparing the results of support vector machine model with those of traditional linear and polynomial fitting methods, it was shown that the prediction results of the model are basically consistent with the actual results, and another advantage of model is that it can carry out deeper mining from more data to improve its robustness. Considering the engineering properties of different category soils are quite different, the authors further analyzed the performance and applicability of model, and established the relationship curve between the forecast bias of each testing sample and its physical indexes. The results indicate that the error of medium compressible soil is smaller than high compressible soil, and the model is more stable and accurate, which could provide a reference for the research of soil compressibility in Shanghai.

This study focuses on establishing a robust relationship between Standard Penetration Test-N values (SPT-N), geotechnical parameters and unconfined compressive strength (qu) using regression analysis. The proposed relationship offers a reliable method for estimating qu based on SPT-N values. A comprehensive dataset comprising approximately 200 soil samples collected from various boreholes across Dhaka city was utilized. Multiple Linear Regression (MLR), Rando-forest Regression (RFR) and AdaBoost Regression techniques were employed to develop a unified correlation model. Evaluation metrics including R-squared (R2), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE), along with Trend-behavior Analysis were employed to assess and compare the performances of the models. Additionally, sensitivity analysis was carried out on the selected model in order to assess the importance of each parameter used to predict qu. Finally, the selected model was compared against the existing empirical models that were published in previous studies. In terms of evaluation metrics and Trend-behavior Analysis, the results showed that the RFR model performed better than the others. Additionally, the selected model outperformed the others, demonstrating the highest R2 score, the smallest RMSE and MAE values and lower residuals compared to the previous models. Hence, the proposed model provides accurate predictions of qu for clayey soil in Bangladesh. Its implementation could ensure more efficient geotechnical designs, specifically adjusted to the geological conditions of the Dhaka region. While previous studies have established regional equations for various parts of the world, our model uniquely has incorporated the Plasticity Index (PI) as a predictor for qu and is specifically calibrated for the geological characteristics of Dhaka city. The findings of this study highlight the effectiveness and applicability of regression analysis in predicting qu for Dhaka's soil properties, thus introducing a valuable tool for enhancing the accuracy and effectiveness of geotechnical assessments and design in the region. [ABSTRACT FROM AUTHOR]

The simple but profound standard equation given in BS 1377:1967 is revisited in this paper. According to the equation, plasticity index (PI) is 2.13 times (or simply twice) the linear shrinkage. This standard relationship is widely recognised and employed when determination of the liquid limit or plastic limit is difficult or not possible. The equation is also used as a basic means of checking the accuracy of test results for the Atterberg limits. Data of 180 natural soil samples were used to statistically evaluate the veracity of the equation. It was found that the BS 1377:1967 equation exhibits excellent accuracy and the equation's veracity for practical engineering use was confirmed. However, the method appears to be correct only up to PI values not exceeding 25% and has greater accuracy at lower PI values (<15%). Other studies in the literature also show that the equation may not apply to some soil types or to soils of particular clay mineral types. These possible limitations thus require further investigation. [ABSTRACT FROM AUTHOR]

Soil compaction in the field is conventionally controlled using maximum dry density, (ρd)max, and optimum moisture content, (w)opt, as the target properties. However, achieving accurate control of these target properties can be difficult due to variation of compaction energy level (CEL) and soil type. Recently, a novel soil compaction control approach using optimum degree of saturation, (Sr)opt, as the target properties has been proposed. It was argued that (Sr)opt can be a better compaction control property as the value is less sensitive to the variation of CEL and soil type. This paper presents an investigation of the compaction characteristics of tropical soils from several locations in Indonesia based on both primary and secondary data. This study was performed by exploring the relationships between (i) dry density (ρd) and Sr, (ii) (ρd) and plasticity index (PI), (iii) (ρd) and CBR, as well as (iv) (ρd) and permeability. This study showed that the (Sr)opt of the soils was 91.2%, with variation between 81.2% and 96.5%. This study also showed that (ρd)max can be related to PI at a given CEL. It is expected that the proposed relationships can be better references for field compaction control practices in Indonesia. [ABSTRACT FROM AUTHOR]

Problems that are often encountered in road construction are poor and unstable soil conditions. Soil conditions greatly affect the design process and the durability of the road. One thing that is usually done to improve soil properties is to add mixed materials to improve the soil properties. The purpose of this study was to determine the effect of adding Waste Glass Powder (WGP) on soil consistency and CBR value. The percentage of WGP used is 2.5%, 5%, 10%, 15% and 25%. The result is that the addition of WGP has significantly improved soil quality. The value of the plasticity index of the soil decreases, which means that the potential for swelling and shrinkage of the soil is also decreased. The CBR value of the soil also increased to 341.04%.

Dredged soil and phosphogypsum are frequently regarded as wasted materials, which require further treatment to control their environmental impact. Hence, phosphogypsum is proposed as a binder to stabilize dredged soil, aiming at efficiently reducing and reusing these waste materials. In this study, the engineering properties of cement-phosphogypsum stabilized dredged soils were investigated through a series of unconfined compression tests, and the effects of plasticity index of original soils on the strength improvement were identified. Then, the microstructure test and mineralogical test were performed to understand the mechanism of physical role of original soils in strength improvement. The results revealed that the unconfined compressive strength significantly decreased with the increase in plasticity index at the same binder content. The essential factor for strength improvement was found to be the formation of cementitious materials identified as calcium silicate hydrate (CSH), calcium aluminate hydrate (CAH), and ettringite (Aft). The normalized integrated intensity of cementitious materials (CSH + CAH + Aft) by pore volume decreased with the increase in plasticity index. Consequently, the density of cementitious materials filling the soil pores controlled the effectiveness of strength improvement. More cementitious materials per pore volume were observed for the original soils with lower values of plasticity index. That is, the higher strength of stabilized soils with lower values of plasticity index was attributed to a packed structure forming by integrated fabric through denser cementitious components. It can be anticipated from the above findings that the effectiveness of stabilization treatment will significantly reduce with the increase in plasticity of origin soil.

A lot of fieldwork is required to assess the safe bearing capacity (SBC) of fine-grained soil using IS Code, along with performing shear parameters to determine angle of internal friction and cohesion. Standard penetration tests are conducted in order to obtain N-value of soil, and evaluating atterberg limits and dry soil density. Here, it is proposed that Adaptive Neuro-Fuzzy Inference System(ANFIS) is adopted to predict fine-grained soil's safe bearing capacity. For this, input parameters considered for ANFIS system are depth of foundation, dry density, liquid limit, plasticity index, Percentage fine fraction, width/Length ratio, and N-Value. A wide range of safe bearing capacity data from various site locations was investigated and trained on. Four different models were developed with variations in membership function for each input, all the models are used with a gaussbell type of membership function. Among the four, the third model is predicting the nearest value with an R2 of 0.9738. Based on the conclusion the ANFIS model is the most reliable technique for assessing the SBC of soils. Investigation of soil properties and estimation of safe bearing capacity will be having more difficulty with respect to skilled person to investigate and time required is also more as dimension of the footing changes SBC also varies. So, to overcome this type of problems my model will give you a best suitable and reliable SBC.

Stand structure, diversity, and plasticity of leaf morphology of Xylocarpus mekongensis were investigated among saline zones in Bangladesh Sundarbans. Stand structure and species diversity were assessed in 27 sample plots (20 m× 20 m) covering 1.08 ha of forest. A total of 11 species were recorded. Out of them, 7, 6, and 9 species were found in fresh water, moderate, and strong saline zone, respectively. Species dominance in terms of importance value showed Heritiera fomes > Excoecaria agallocha > Bruguiera sexangula > Xylocarpus mekongensis in fresh water zone; H. fomes > E. agallocha > Avicennia officinalis > Ceriops decandra in moderate saline zone. E. agallocha > Sonneratia apetala > H. fomes > C. decandra in strong saline zone. Species diversity decreased from fresh water to strong saline zone. The findings showed a wide range of leaf morphological plasticity of all the parameters within and among saline zones. Leaf index, plasticity index, and specific leaf area were maximum in fresh water zone than of others. The findings of PCA revealed clear evidences of plastic behavior of leaf morphological parameters. Thus, the plasticity of leaf morphology might contribute as an influential biological signs of forthcoming climate change events.

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Clay minerals are an important indicator of soil plasticity, influencing clay activity. This study aimed to elucidate the effect of clay minerals, organic C and primary minerals on the Atterberg limit and clay activity. The study was conducted in the Kemuning sub-watershed, Jember, East Java. The study began by preparing a thematic map to determine sample points with stratified random sampling. They were taken as many as 35 disturbed soil sample points at 0-20 cm from the surface. Soil texture was determined using the pipette method, and organic C was determined by the spectrophotometer method. The liquid limit and plastic limit were used to determine the plasticity index. A microscopic analysis of sand mineralogy was carried out to compare activity values with a magnification of 20-40 times to assess the primary soil minerals. The results showed that clay and C-organic affect fluidity, plastic limit, and plasticity index. The presence of andesine, albite, olivine, and orthoclase in the sand fraction and the low clay activity indicated that kaolinite dominated the study area, with smaller amounts of illite and halloysite.

As a common geological material, soil is a key aspect of construction engineering. Soil has typical multi-scale characteristics, but current multi-scale methods analyze these characteristics only in regard to geometric space. More exploration of the coupling influence mechanism of the basic properties of particles on the microstructure and macroscopic properties of soil is needed. This study analyzed the influence of geometric scale and mineral composition on the surface energy of particles at the microscopic level for development of the energy multi-scale method. Experiments were performed to determine the influence of mineral composition and particle size on the plasticity index (Ip) of the soil, and experimental results are discussed and interpreted quantitatively using the energy multi-scale method. The conclusions derived from this work are as follows: 1) the mineral composition and particle size of the soil can cause interface and surface effects; 2) the comprehensive ratio of micro-force to weight (CRFW) of the particles can be determined using the energy multi-scale method and quantitatively reflects the influence of particle size and mineral composition on the microscopic properties of the soil; and 3) the energy multi-scale method explains the mechanism of the plasticity index of soil and has allowed identification of a new division of soil plasticity. When the CRFW was used as the control index, the plasticity index of the three materials was practically the same, even if the mineral composition and particle sizes of the three materials were different.

Copyright of Journal of Soil Science & Plant Nutrition / Toprak Bilimi ve Bitki Besleme Dergisi is the property of Soil Science Society of Turkey and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bruguiera sexangula (Lour.) Poir is an exclusive evergreen mangrove species to the Sundarbans of Bangladesh. It grows well in moderate saline zones with full sunlight. This study presents leaf morphological plasticity in B. sexangula to saline zones. Leaves were sampled from different saline zones and various morphological traits were measured. The results exposed a wide deviations of leaf size parameters: leaf length varied 6.6–17.3 cm; width 2.7–7.8 cm; upper quarter width 2.2–6.5 cm; down quarter width 2.5–7.3 cm; and petiole length 0.17–1.43 cm. Leaf length was significantly larger in fresh water than in other salinity zones, whereas, leaf width, upper and lower leaf quarters were significantly larger in medium saline zone. Leaf shape parameters showed a large variation among saline zones. Leaf base angle was significantly larger in both medium and strong salinity zones. Tip angle was significantly greater in medium salinity zone. Leaf perimeter was significantly larger in fresh water but leaf area was significantly bigger in medium saline zone. Leaf index and specific leaf area were maximum in moderate saline zone. Plasticity index was the highest in moderate saline for almost all the parameters presented. The ordination (PCA) showed clusters of leaf samples although there were some overlap among them which suggested a salt-stress relationship among salinity zones. The results indicate that B. sexangula had a plasticity strategy on leaf morphological parameters to salinity in the Sundarbans. This study will provide basic information of leaf plasticity of this species among saline zones which will help for site selection of coastal planting and will also provide information for policy makers to take necessary steps for its conservation. [ABSTRACT FROM AUTHOR]

This article explores soil classification methods and the influence of using dispersing agents in various amounts for the soil particle size analysis. Laboratory testing with different dispersing agents was conducted to analyze the effects of sodium hexametaphosphate and lithium carbonate for two different soils with plasticity indices indicating one to be with low plasticity (PI = 8.23 %) and the other one with high plasticity (PI = 39 %). The article highlights differences in the granulometric fractions reported for each soil and usage of the same dispersing agent but in various amount. Thus, the classification of soils is influenced by the amount of the used dispersing agents, recommendations of standards being different in time and countries. These findings contribute to a better understanding of the anticipated behavior of fine soils and provide useful insights for various geotechnical applications.