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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.

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]

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]

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.

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]

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.

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.

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.

Background Progesterone is increasingly being used in women at high risk for preterm labor and for maintenance tocolysis. Ultrasound evaluation of uterine in pregnant women in the second trimester of pregnancy can be a predictor of birth complications. Objective To study the effect of vaginal progesterone on uterine by doppler sonography among women in the second and third trimesters of pregnancy who are at risk of preterm labor. Patients and methods A prospective study was carried out on 60 patients attending Obstetrics and Gynecology Department, Menoufia Teaching Hospital, Menoufia, Egypt, during the period from March 2019 to March 2020. The patients were admitted to the hospital for preterm labor, which was arrested by acute tocolysis within 48 h. All participants were subjected to routine baseline investigations and Doppler flow assessment. Results There was a highly statistically significant difference (P < 0.001) in uterine artery pulsatility index (PI) before and after treatment (P = 0.000). Uterine artery PI decreased significantly after treatment (0.817 ± 0.16) than before treatment (0.969 ± 0.27). Uterine artery PI decreased significantly after treatment than before treatment in different periods of gestation (weeks). Moreover, there was no statistically significant difference (P>0.05) between the studied women as change in umbilical artery PI before and after treatment in different periods of gestation (weeks). Moreover, uterine artery PI was significantly correlated (P < 0.05) with period of gestation (week) before and after progesterone treatment. Conclusion Uterine artery pulsatility index (PI) decreased significantly after progesterone treatment than before treatment in different periods of gestation (weeks). Umbilical artery PI and middle cerebral artery Doppler PI were not significant different among the studied patients before and after progesterone treatment in different periods of gestation (weeks). Uterine artery PI and middle cerebral artery Doppler PI were negatively associated with period of gestation (week) before and after progesterone treatment.

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. [ABSTRACT FROM AUTHOR]

Soil tensile strength is important in different geotechnical structures such as earth dams, roads, airports, landfills, and retaining walls. There are several experiments to study the tensile behavior of soils with different advantages and disadvantages. One of the methods used to investigate soil tensile behavior is tensile hollow cylinder apparatus, which has seldom been used. In this research, a hollow cylindrical device to measure the tensile properties of soil was built and operated. This device can apply tensile stress evenly to the entire soil sample so that stress concentration does not occur at any point in the sample. After designing, manufacturing, and assembling the apparatus, validation tests were performed to ensure the device was operating well. The results of the repeatability tests show the accurate performance of the device. Also, in this study, the effect of plasticity index (PI) on the tensile behavior of kaolinite clay was investigated. Clayey soils with plasticity indices of 10 and 24% were selected. The results show that for clays with a similar mineral, the tensile strength increases and the tensile failure strain decreases with increasing the plasticity index.

Geotechnical investigation, in hilly areas, for high-rise projects, becomes a problematic issue and costly process due to difficulties in mobilization and assembling the drilling equipment on mountainous terrains. The objective of this study is to map soil properties of study areas, especially at inaccessible sites, for reconnaissance. Digital soil maps for Tehsil Murree, Pakistan, have been developed using the emerging Geographical Information System (GIS). The research work involved the creation of an exhaustive database, by collecting and rectifying geotechnical data, followed by the digitization of the acquired data through integration with GIS, in an attempt to visualize, analyze and interpret the collected geotechnical information spatially. The soil data of 205 explanatory holes were collected from the available geotechnical investigation (GI) reports. The collection depth of soil samples, which were initially used for the design of deep and shallow foundations by different soil consultancies in the Murree area, was approximately 50 ft. below ground level. Appropriate spatial interpolation methods (i.e., the Kriging) were applied for the preparation of smooth surface maps of soil standard penetration tester number values, soil type and plasticity index. The accuracy of developed SPT N value and plasticity maps were then evaluated using the linear regression method, in which the predicted values of soil characteristics from developed maps and actual values were compared. SPT N value maps were developed up to a depth of 9.14 m below ground level and at every 1.52 m interval. The depth of refusal was considered in the developed maps. Soil type and plasticity maps were generated up to 15.24 m depth, again at every 1.52 m intervals, using color contours, considering the maximum predicted foundation depth for high-rise projects. The study has implications for academics and practitioners to map the soil properties for inaccessible sites using GIS, as the resulting maps have high accuracy. [ABSTRACT FROM AUTHOR]

Background Progesterone is increasingly being used in women at high risk for preterm labor and for maintenance tocolysis. Ultrasound evaluation of uterine in pregnant women in the second trimester of pregnancy can be a predictor of birth complications. Objective To study the effect of vaginal progesterone on uterine by doppler sonography among women in the second and third trimesters of pregnancy who are at risk of preterm labor. Patients and methods A prospective study was carried out on 60 patients attending Obstetrics and Gynecology Department, Menoufia Teaching Hospital, Menoufia, Egypt, during the period from March 2019 to March 2020. The patients were admitted to the hospital for preterm labor, which was arrested by acute tocolysis within 48 h. All participants were subjected to routine baseline investigations and Doppler flow assessment. Results There was a highly statistically significant difference (P < 0.001) in uterine artery pulsatility index (PI) before and after treatment (P = 0.000). Uterine artery PI decreased significantly after treatment (0.817 ± 0.16) than before treatment (0.969 ± 0.27). Uterine artery PI decreased significantly after treatment than before treatment in different periods of gestation (weeks). Moreover, there was no statistically significant difference (P0.05) between the studied women as change in umbilical artery PI before and after treatment in different periods of gestation (weeks). Moreover, uterine artery PI was significantly correlated (P < 0.05) with period of gestation (week) before and after progesterone treatment. Conclusion Uterine artery pulsatility index (PI) decreased significantly after progesterone treatment than before treatment in different periods of gestation (weeks). Umbilical artery PI and middle cerebral artery Doppler PI were not significant different among the studied patients before and after progesterone treatment in different periods of gestation (weeks). Uterine artery PI and middle cerebral artery Doppler PI were negatively associated with period of gestation (week) before and after progesterone treatment. [ABSTRACT FROM AUTHOR]

Ten coarse-fine mixtures (CFM) (intermediate soils) having fines contents (FC) of 0%, 12%, 20%, 30%, 40%, and plasticity indices (PI) of 5% and 15% were prepared in the laboratory by mixing different fractions of gravel, sand, nonplastic silt, kaolin, and bentonite. Index properties, volume change during saturation, specific surface area (SSA), and saturated hydraulic conductivity of CFM were investigated. For compacted CFM, a FC=15% (for PI=5%) and FC=12% (for PI=15%) represent the transition between coarse- and fine-dominant behavior based on intergranular void ratio. The total SSA of CFM may be estimated from the weighted average of SSA determined individually for each soil fraction since the SSA of the cohesive portion was observed to be linearly proportional to the percent fractions of kaolin and bentonite. Hydraulic conductivity estimations based on the SSA of soils proposed by the Kozeny–Carman equation underpredicted the hydraulic conductivity of CFM by one to four orders of magnitude. Alternatively, the formulations from consolidation theory and modified Hazen's correlation utilizing effective particle size, D10 , and void ratio, e, estimated the hydraulic conductivity within an order of magnitude. Although hydraulic conductivity decreased with the increase of FC and PI, a smaller amount of decrease was observed in low plastic CFM. [ABSTRACT FROM AUTHOR]

Abstract Background Geologic and geotechnical conditions of soils where Nanka and Ajali Formations outcropped in Anambra Basin, Southeastern Nigeria were investigated and accessed. This was done using detailed mapping and mechanical soil laboratory tests to unravel the genesis and continued expansion of gully erosion in the study areas. Results Field study revealed that gully erosions are more pronounced in the study area with poor vegetation cover and a high degree of slope steepness. Grain size analysis revealed that the soils of the Nanka Formation have an average sand content value of 90.90% (sandy) and silt content value of 3.0% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 5.29%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.67 × 10–3 cm/s. The compaction test further revealed that the soils are loosely compacted. The soils for the Ajali Formation have an average sand content value of 95.10% (sandy) and silt content value of 1.43% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 2.70%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.70 × 10–3 cm/s. The compaction test revealed that the soils are loosely compacted. Conclusion After field surveys and laboratory analyses, it was found that the gully erosions have been developing respectively on steep slopes and non-vegetated areas, and their genesis facilitated by the cohesionless and very permeable nature of the sandy formations. Following those key findings, it was proposed many practices (agronomic and engineering mainly) that can help mitigate the formations as well as the expansion of this very damaging hazard type. The potential implications of these gully erosion include damaging of buildings, residential houses, bridges, and roads, loss of farmland and vegetation, isolation of villages and towns, increased migration of inhabitants as well as degradation of agricultural fertile land.

A study on the effect of sisal fibre and waste plastic strips on tropical black clay (also called Black cotton soil, BCS) was carried out. Tests piloted on the natural and treated soil consist of California bearing ratio (CBR), Atterberg limits and compaction for different percentages inclusion of sisal fibre (0, 0.5, 1, 1.5 and 2%) and waste plastic strips (0, 0.5, 1, 1.5 and 2%) by dry weight of soil. Results obtained showed that the liquid limit of BCS initially fluctuated between 43.4% and 55.9% at 1% sisal fibre content, then dropped to 49.4% at 2% sisal fibre content. In the case soil treated with waste plastic strips, liquid values increased from 43.4% for the natural soil to a highest value of 58% at 1% waste plastic strips and thereafter decreased to 49.15% at 2% waste plastic strips content. Plastic limit for both BCS-sisal fibre/waste plastic strips initially decreased from its natural value of 25.78 to 15.55 and 14.77% when treated with sisal fibre and waste plastic strips respectively at 0.5% admixtures content. In the case of plasticity index, values initially increase from its natural value of 17.66% to peak values of 35.39 and 43.23% for sisal fibre and waste plastic strips treated soil respectively, and thereafter decreased. Maximum dry density (MDD) initially increased from 1.55 mg/m3 at 0%, to 1.60 mg/m3 at 0.5% and thereafter decreased to 1.53 mg/m3 at 2% of fibre content. In the case of samples treated with waste plastic strips. The MDD progressively increased as the amount of waste plastic strips increased. OMC show an overall trend of increase for BCS treated with sisal fibre, and a general trend of decrease for soil treated with waste plastic strips. The CBR values initially lessened from their natural value of 13.59% to 4.76% at 1% sisal fibre and subsequently increased to 10.57% at 2% sisal fibre. Similar behaviour was observed for soil modified with waste plastic strips. Based on the results, BCS/waste plastic strips improved the soil more than BCS/sisal fibre treated soil and is recommended at optimal 2% waste plastic strips for geotechnical engineering application such as road payment. [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. [ABSTRACT FROM AUTHOR]

The running-in process is the initial process for the new moving parts wearing against each other to establish the shape adjustment that will regulate them into a stable relationship for the rest of their working life. The objective of this research is to investigate and evaluate the running-in process by using disk-on-block line contact device. Due to its empirical nature and well-ploughed analysis, an asperity micro-contact model is considered. The experiment is performed by varying the surface roughness of the block with rigid smooth sphere surface under specific condition. The effects of surface roughness, load, speed, and lubrication on the running-in behaviour is studied. The running-in process encourage plastic deformation of asperities and created microstructural changes on contact surfaces. The theoretical and experiment result shows that the plasticity index ps, surface roughness parameter b, real contact area ratio * A0 and specific film thickness l is influenced by the running-in process.

Copyright of Investigación e Innovación en Ingenierías is the property of Universidad Simon Bolivar 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.)

Electrokinetic (EK) treatment is an innovative, cost-effective in situ ground modification technology. The EK treatment uses a combination of low-voltage direct-current, electrodes, and ionic solutions across problematic soil to improve the ground conditions. This study aims to model the effect of changing electrode length (le) on the performance of the EK treatment on the engineering properties of fine-grained problematic soils. The consideration of the changing electrode lengths (le), varying soil depths (ds), and lengthwise anode to cathode distances (dA↔E), in the soil block samples, is in the form of the laboratory model test tank. The significant performance of the experimental tests was with changing electrode lengths of 0.25le (7.5 cm), 0.50le (15.0 cm), 0.75le (22.5 cm), and 1.0le (30.0 cm). The study analyzed the test data obtained from the Atterberg limit and one-dimensional swelling tests at different extraction points of the EK treated soils in the test tanks. Furthermore, the study carefully analyzed the effect of changing electrode length (le) on the performance of the EK treatment. The results of the Design of Experiment (DOE) model analysis revealed that the effect of changing electrode length (le) on the plasticity index (PI), and swelling potential (SP) of the EK treated soils, was significant. For a specific soil depth (ds), the electrode lengths (le) of 0.50le and 0.75le were significantly effective in reducing the PI, and the SP of the EK treated soils. Unlike other studies in the literature, the use of DOE analysis in the present study enabled the detection of the significant input factors and their interactive effects on the PI and the SP, thus, enabling the practicing engineers to navigate accurate design models for large in situ applications. [ABSTRACT FROM AUTHOR]

Conical picks are by far the most widely used drag type cutting tools employed on partial face rock excavation machines. The cutting force and specific energy are two important design parameters for the conical pick performance, and the rock cutting testing is considered as the promising tool for determining these parameters. In the absence of an instrumented cutting rig, researchers generally rely on empirical predictive plots. For this, this paper suggests predictive plots for estimating the cutting force and specific energy, in consideration of the cutting depth to define the cuttability with conical picks. In this context, rock cutting tests were carried out on six volcanic rock samples with varying cutting depths using the unrelieved and relieved cutting modes. The cutting force and specific energy were correlated with the uniaxial compressive strength, Brazilian tensile strength, elasticity modulus, and plasticity index. Predictive plots were proposed for different cutting depths in the unrelieved and relieved cutting modes and exponential relationships were obtained among the cuttability parameters, and mechanical and elastoplastic properties of rocks.

Abstract Shallow landslides occur frequently on the Aso volcanic mountains. The soil materials on the Aso volcanic mountains consist of tephra layers formed by volcanic activities. This study is aimed to specify the physical properties of soil that correlate with the sliding layer of a shallow landslide on the volcanic mountain area. Tephra layers consist of kuroboku and scoria layers and the differences between these layers were specified using the physical properties of soil methods. Results showed that the plasticity index and the fine fraction content can be used for estimating the sliding layer in the Aso volcanic area.

Abstract Structural failure of buildings, roads, and other infrastructures has led to the loss of lives and monumental damage to the economy. In developing countries such as Nigeria, the failures are always attributed to the nature/type of soils in the area without considering other factors. With the increase in civil engineering constructions and the scramble for a limited portion of competent soils for such constructions, land, therefore, is becoming man’s most priced commodity for agriculture, residential and industrial purposes. No works of such have been done in the area, it is, therefore, imperative to study the cause(s) to prevent further loss of lives and the negative effects of such on the economy. The study was carried out at Panyam and some surrounding localities on latitudes N9021′ and N9026′ and longitudes 9011′E and 9016′E an area of 72 km2. A total of forty samples were collected out of which twenty were selected for swelling potentials determination due to their cohesive nature within the 1.5 m depth. To characterize the swelling of the soils, inferential testing methods; direct method comprising Liquid Limit and Plasticity Index with values ranging from 30% – 70% and 10% – 27% respectively, and the indirect method (Free Swell Index, FSI) whose values range from 9.1% – 90% were used. Most of the soils analyzed based on the geotechnical standards were categorized relatively safe for civil infrastructure. Structural studies employed the direct measurements of surface structures to get the orientations of structures measured. Landsat image and Total Magnetic Intensity (TMI) map of the area was acquired from the Nigerian Geological Survey Agency (NGSA) for subsurface structural analysis. The RTP-TMI (reduce to pole) grid data of the area were processed to improve magnetic anomalies associated with edges of surface/near-surface geological structures using the MAGMAP two-dimensional fast fourier transform (2D-FFT) filters package in Oasis Montaj v7.2 software. Geophysical studies using aeromagnetic data at a near-surface depth of 40 m and fractures measured on the surface both revealed a major trend in the NNE – SSW. It was observed that structures constructed across the major trend suffered little to moderate damage while those constructed along the major fractures trend suffered severe damage. It was concluded that both soils and fractures played individual roles in the collapse of infrastructure in the area.

Using discarded iron ore powder to settle subgrade soil will improve the characteristics of black cotton soil. The soil's engineering properties are analysed using various tests, such as specific gravity, grain size analysis, Atterberg's limits, compaction properties, and unconfined compressive strength. These tests examine the classification of the soil, the optimum moisture content (OMC), the maximum dry density (MDD), the strength of the soil, and other variables. The black cotton soil (BCS) was taken from Ghatkesar Mandal in the Malkalgiri-Medchal region, while the iron ore was procured from a small-scale local enterprise. For this, a clay soil sample with a medium degree of plasticity was combined with iron ore powder in concentrations ranging from 0% to 20% with a 5% increment. The data obtained demonstrated a steady rise in specific gravity with the addition of scrap iron ore and raised from 2.54 to 2.81 when it comes to unconfined compressive strength. Adding more iron ore increased the UCS to stabilize the soil from 149.31kPa to 232.22kPa. The OMC increased from 16% to 12.5%, MDD from 1.86gm/cc to 1.98gm/cc and Plasticity Index from 42.8% to 28.08%. For all mixes, the soil is well-graded. The results demonstrate that iron ore waste can successfully stabilize the soil.

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering 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.)

Phenotypic plasticity is often considered important for invasive plant success, yet relatively few studies have assessed plasticity in both native and invasive populations of the same species. We examined the plastic response to temperature for Bromus tectorum populations collected from similar shrub-steppe environments in the Republics of Armenia and Georgia, where it is native, and along an invasive front in California and Nevada. Plants were grown in growth chambers in either 'warm' (30/20 °C, day/night) or 'cold' (10/5 °C) conditions. Invasive populations exhibited greater adaptive plasticity than natives for freezing tolerance (as measured by chlorophyll a fluorescence), such that invasive populations grown in the cold treatment exhibited the highest tolerance. Invasive populations also exhibited more rapid seedling emergence in response to warm temperatures compared to native populations. The climatic conditions of population source locations were related to emergence timing for invasive populations and to freezing tolerance across all populations combined. Plasticity in growth-related traits such as biomass, allocation, leaf length, and photosynthesis did not differ between native and invasive populations. Rather, some growth-related traits were very plastic across all populations, which may help to dampen differences in biomass in contrasting environments. Thus, invasive populations were found to be particularly plastic for some important traits such as seedling emergence and freezing tolerance, but plasticity at the species level may also be an important factor in the invasive ability of B. tectorum. © 2014 Springer International Publishing Switzerland.

Introduction: the following study focuses on the granulometric analysis of soils, using a soil from the town of Cuauhtémoc, Villa Flores, Chiapas, Mexico, to determine its possible use in the elaboration of Compressed Earth Blocks (CEB). The purpose of the study is to achieve adequate mechanical strength without using chemical stabilization Method: the initial characterization procedure of the soil samples was developed by means of granulometric determination and consistency limits, which made it possible to identify the soil by its granulometric curve and resistance to axial compression. The discussion arose from the identification in the existing regulations for CEB in Spain and Mexico that they establish too wide granulometric intervals and do not seem to give importance to achieving an optimal accommodation of the granulometric curve, forcing chemical stabilization. A granulometric range for CEB was idealized by adjusting maximum and minimum limits of the different sizes of particles that make up the samples and the percentage of initial water was established from the plasticity index. Afterwards, 3 series were elaborated with five samples of compressed earth in each configuration, varying the granulometric curve, percentage of water and elaboration pressure to improve their resistance to compression. Results: the results describe a notable improvement in the behavior of the soil as a compressed block when the granulometric adjustment is carried out. The CEB mix design was improved from 32.5 kg / cm² to 54.75 kg / cm² by adjusting the percentage of water and nominal brewing pressure. Conclusion: it is concluded that it is possible to optimize the use of soil for construction by controlling the granulometry, water content and nominal pressure of the raw material, achieving mechanical strengths greater than 50 kg / cm² without using cement, asphalt, or lime as stabilizers. [ABSTRACT FROM AUTHOR]

Relevance. Classification of organomineral soils according to state standards require correction. Methods for determining classification consistency indicators give excessive values moisture content of the plasticity and liquid limits due to the high content of organic matter. Due to imperfect standards, their results are unreliable and the grounds are incorrectly classified, which leads to errors in calculations of the base of constructions. The expediency of determining the consistency of organics containing soils is doubtful, and in order to reduce costs in engineering and geological investigations, the authors propose to consider in detail the problem of classification of organomineral soils by the example of numerous experimental data obtained for soils in the West Siberian region and recommend еру changes to existing standards. The main aim of the research is to identify the relationship between consistency indicators and organic matter content based on the experimental studies of organic-mineral soils of Western Siberia and justify the use of the Atterberg limits applied for mineral soils. Object: organomineral clay soils typical for Western Siberia, picked on the territory surroundings of the city of Tomsk, oil and gas fields of Tomsk region and Khanty-Mansiysky Autonomous District. Research methods include a method for determining limits of liquid and plasticity (wL and wp) and organic content (Ir), as well as by analyzing the results using MS Excel and Statistica. Results. The authors have carried out the review and analysis of foreign methods for determining the classification indexes of consistency in engineering-geological surveys and considered the problems of their carrying out and applications for soils containing organic substances. The determinations of organic matter, moisture content and consistency were carried out, significant interrelations between the indices were obtained and regression equations were compiled. As a result, inconsistencies with the current classification of organomineral clay soils due to overestimation of the consistency indices are revealed, therefore, in relation to their uninformativeness, it is recommended to abandon their use for organics containing soils.

Prediction of the free swell index of the expansive soil using artificial neural network has been presented in this paper. Input parameters for the artificial neural network model were plasticity index and shrinkage index, while the output was the free swell index. Artificial neural network algorithm used a back propagation model. Training of the artificial neural network model was conducted on the data collected from literature, and the weights and biases were obtained which described the relation among the input variables and the output free swell index. Further, the sensitivity analysis was performed, and the parameters affecting the free swell index of the expansive soil were identified. The sensitivity analysis results indicated that the plasticity index (63.97 %) followed by shrinkage index (36.03 %) was affecting the free swell index in this order. The study shows that the prediction accuracy of the free swell index of the expansive soil using artificial neural network model was quite good.

Geotechnical investigation, in hilly areas, for high-rise projects, becomes a problematic issue and costly process due to difficulties in mobilization and assembling the drilling equipment on mountainous terrains. The objective of this study is to map soil properties of study areas, especially at inaccessible sites, for reconnaissance. Digital soil maps for Tehsil Murree, Pakistan, have been developed using the emerging Geographical Information System (GIS). The research work involved the creation of an exhaustive database, by collecting and rectifying geotechnical data, followed by the digitization of the acquired data through integration with GIS, in an attempt to visualize, analyze and interpret the collected geotechnical information spatially. The soil data of 205 explanatory holes were collected from the available geotechnical investigation (GI) reports. The collection depth of soil samples, which were initially used for the design of deep and shallow foundations by different soil consultancies in the Murree area, was approximately 50 ft. below ground level. Appropriate spatial interpolation methods (i.e., the Kriging) were applied for the preparation of smooth surface maps of soil standard penetration tester number values, soil type and plasticity index. The accuracy of developed SPT N value and plasticity maps were then evaluated using the linear regression method, in which the predicted values of soil characteristics from developed maps and actual values were compared. SPT N value maps were developed up to a depth of 9.14 m below ground level and at every 1.52 m interval. The depth of refusal was considered in the developed maps. Soil type and plasticity maps were generated up to 15.24 m depth, again at every 1.52 m intervals, using color contours, considering the maximum predicted foundation depth for high-rise projects. The study has implications for academics and practitioners to map the soil properties for inaccessible sites using GIS, as the resulting maps have high accuracy.

The objective of this research was to investigate the effect of adding thermally treated clay on some engineering properties of the untreated expansive clayey soil. Three expansive clayey soil samples obtained from three different sites in the south of Syria have been investigated. They were thermally treated up to three different levels (450°C, 650°C and 850°C) for 3 hours. Three replacement levels of thermally treated clay were used, i.e. 0%, 10% and 20%. The X-ray diffractometer (XRD) technique has been used to detect the crystalline and glassy phase in the clayey samples before and after the thermal treatment. Pozzolanic activity of the thermally treated clayey soil has been studied using the modified Chapelle test and the mechanical strength test at each of the temperature levels. Atterberg limits, compaction, free swell, swelling pressure and linear shrinkage have particularly been investigated. Test results revealed the positive effect of thermally treated clay when added to the natural soil. Plasticity index (PI) was reduced by about 60% when 20% thermally treated clay was added to the natural soil. In addition, 6% lime was added to further investigate the combined effect of lime and calcined clay on the properties of the clayey expansive soil. All investigated properties were significantly improved when 20% thermally treated soil and 6% lime were added together. For instance, swelling pressure and linear shrinkage values were reduced to less than 15% or even much less when compared with those of the natural soil. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis were employed as well.

Background: Geologic and geotechnical conditions of soils where Nanka and Ajali Formations outcropped in Anambra Basin, Southeastern Nigeria were investigated and accessed. This was done using detailed mapping and mechanical soil laboratory tests to unravel the genesis and continued expansion of gully erosion in the study areas. Results: Field study revealed that gully erosions are more pronounced in the study area with poor vegetation cover and a high degree of slope steepness. Grain size analysis revealed that the soils of the Nanka Formation have an average sand content value of 90.90% (sandy) and silt content value of 3.0% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 5.29%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.67 × 10–3 cm/s. The compaction test further revealed that the soils are loosely compacted. The soils for the Ajali Formation have an average sand content value of 95.10% (sandy) and silt content value of 1.43% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 2.70%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.70 × 10–3 cm/s. The compaction test revealed that the soils are loosely compacted. Conclusion: After field surveys and laboratory analyses, it was found that the gully erosions have been developing respectively on steep slopes and non-vegetated areas, and their genesis facilitated by the cohesionless and very permeable nature of the sandy formations. Following those key findings, it was proposed many practices (agronomic and engineering mainly) that can help mitigate the formations as well as the expansion of this very damaging hazard type. The potential implications of these gully erosion include damaging of buildings, residential houses, bridges, and roads, loss of farmland and vegetation, isolation of villages and towns, increased migration of inhabitants as well as degradation of agricultural fertile land. [ABSTRACT FROM AUTHOR]

Sundri (Heritiera fomes Buch.-Ham.) is an evergreen mangrove tree species found abundantly in the freshwater zone of Sundarbans, Bangladesh and scattered in moderate or strong saline zones of the forest. H. fomes grows well in top canopy having full sunlight and even in full shade under the canopy. This study presents the plasticity of leaf morphological and anatomical characteristics in H. fomes due to variation of light intensity at different canopy depths and of salinity in different saline zones of Sundarbans. This study was conducted in two steps, firstly the light intensity and leaf phenotypic variations at different canopy depths (one-meter interval) in the fresh water zone of Sundarbans, secondly the leaf phenotypic variations in three saline zones having variable light environment at different canopy positions (top, middle and bottom) in each zone. Leaf samples were collected from three different salinity zones and each canopy positions and various morphological and anatomical characteristics were quantified. A wide range of variations were observed in the leaf parameters measured among the salinity zones of the Sundarbans and the canopy positions. The canopy of H. fomes showed an exponentially decreasing light gradient. Leaf plasticity index (PI) of all the parameters was developed for the salinity zones and the canopy positions of the Sundarbans. The ordination plots (PCA) suggested clear morphological and anatomical shift of the samples collected from different saline zones and canopy positions showing relationship to light and salt stresses in natural environment. Our results provide clear evidence on plastic strategy of H. fomes against salinity and light gradients in the Sundarbans.

Geotechnical engineering like any other engineering field has to develop and cope with new technologies. This article intends to investigate the spatial relationships between soil’s liquid limit (LL), plasticity index (PI) and Liquidity index (LI) for particular zones of Sulaymaniyah City. The main objective is to study the ability to produce digital soil maps for the study area and determine regions of high expansive soil. Inverse Distance Weighting (IDW) interpolation tool within the GIS (Geographic Information System) program was used to produce the maps. Data from 592 boreholes for LL and PI and 245 boreholes for LI were used for this study. Layers were allocated into three depth ranges (1 to 2, 2 to 4 and 4 to 6) m. A total of 1396 observations were used for producing the maps for both LL and PI, and 371 data for LI. Based on the results, the IDW method gives reasonable predictions depending on the results of R2 and RMSE. The results also showed that the study area has relatively large zones of high expansive soil that must be taken into considerations before performing any construction activity. These maps are essential for helping geotechnical engineers in making decisions and visualizing soils’ behaviors.

The effect of material properties and surface roughness on the contribution of asperities and sphere bulk displacements to the total displacement of a rough spherical contact is investigated. A dimensionless transition load, above which the contribution of the bulk displacement exceeds the contribution of the asperities displacement, is found as a function of the plasticity index and dimensionless critical interference of the sphere bulk. A criterion is proposed for evaluating the importance of surface roughness in calculating the displacement of a rough spherical contact. Some experimental results with a spherical micro-contact are presented to verify the model.

Article determins a correlation between the values of the plasticity and liquidity index (IP, IL) of cohesive soils achieved by various laboratory methods (on the basis of Casagrande apparatus and cone penetrometer method) and consists research results on natural clayey soils of known origin and strictly defined genetic features, described in detail in terms of particle size and mineralogy (the North Polish ablation boulder clays and varved clays).

In landfills, due to their low hydraulic conductivity, compacted clays (CC) are commonly used in multilayered structures as base liners and cover systems. Nevertheless, the hydraulic performances of the CC layer can be affected by temperature alterations. The CC barrier of cover systems is exposed to heating caused by waste degradation processes as well as by the air temperature fluctuations, including freezing and thawing and high temperatures. Exposition occurs especially during transitory configurations when the final cap is not completed with the protective soil layers. In the present work, four clayey soils of varying plasticity all suitable for landfill barriers according to the international standard requirements are tested with respect to their sensitivity to thermal stresses in terms of hydraulic conductivity changes. For each material, experimental tests are performed on compacted specimens comparing the values obtained soon after compaction with the ones obtained after exposition to freezing–thawing or drying processes, the latter caused by heating up to 60 °C. The results show that freezing–thawing is more detrimental than heating, since the first can increase the hydraulic conductivity by up to about 20 times, while the second by less than 10 times. The soils of medium plasticity are the most affected, while the ones with high plasticity show the ability to partially withstand the effects of the investigated thermal alterations. This behavior seems related to the water absorption capacity of the material. The results suggest that the optimum water content acquired from the Proctor Standard curve seems to be a suitable indicator of this partial recovery potential. [ABSTRACT FROM AUTHOR]

This study presents the results of in-situ field stabilization of clay soil using lime, dolerite and quartzite powders. The rock samples were collected from Oghi village and Misri Banda village of Khyber Pakhtunkhwa Province, Pakistan. A 415m2 site comprised of loose clay in Haripur district of Khyber Pakhtunkhwa was selected for field stabilization. In order to implement the experimental plan, eight test pits were dug and soil samples were collected from each pit to determine their major geotechnical properties. The raw soil contained kaolinite, illite and montmorillonite and hence characterized as CH type according to the Unified Classification System. The addition of 6% lime was found to produce the most positive impact on soil properties. Following a steady augment by 10%, a maximum of 30% dolerite and quartzite powders were separately mixed with each of the 6% lime-added soil samples. The resulting mixed soils were placed back into their respective pits and compacted using compaction vibrator. Standard penetration, field density and plate load tests were performed on each test pit. Finally, soil samples were extracted from all the test pits and the values of their direct shear box and Atterberg limits were measured. The results demonstrate that the addition of dolerite and quartzite leads to a significant increase in the bearing capacity, dry density, penetration resistance and angle of internal friction and thus improves the performance of the formerly lime-stabilized soil by drastically decreasing its compressibility. The resulting improvement is mainly due to the denser and less hydrophilic character of the constituents of the added rock powders as compared with the lime and raw soil. It has also been found that the magnitude of impact on the soil properties by dolerite and quartzite is notably different owing to the difference in mineralogical composition and physical characteristics of individual minerals present in both rock types. This study would help construction engineers for better soil treatment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

This study presents the effect of high plasticity on swell potential, swelling pressure and micro-structural characteristics of kaolinite-bentonite mixed clays. Five different mix ratios of kaolinite bentonite mixture of 100:0, 90:10, 75:25, 50:50 and 25:75 in % by weight of dry kaolinite were used. All five synthesised soils were then mixed with 0%, 5% and 8% of cement by weight of dry soil, cured for 28 days and subjected to the Atterberg limit, one-dimensional oedometer and scanning electron microscope test. The inclusion of 5% and 8% cement reduces the plasticity index of the treated soils as the percentage of bentonite increases. The effects on plasticity of treatment with 5% and 8% cement after a 28-day curing period was evaluated, and the results show that reduction in plasticity index resulted in decreased swell potential and swelling pressure of the kaolinite-bentonite mixed clays. The results of microstructural analysis of 5% cement-treated soils show formation of flocculated fabric and cementation of soil particles, and filling with cementitious compounds of the voids of flocculated fabric in the soil. The reduction in swell can be attributed to the resulting compacted and dense mass of treated soils due to cementation of soil particles and cation exchange. The complex swell behaviour of high-plasticity kaolinite-bentonite mix is explained using the one-dimensional oedometer test, by further experimental study and examination of the microstructure of treated soils. [ABSTRACT FROM AUTHOR]