Soil Adhesion Research Articles

Effect of Tine Depth and Width on Soil Failure Angle, Cutting Coefficients and Power in Three-Dimensional Case: Computer Modeling

The dynamic response of soil to farm implements is a main factor in determining their performance. The interaction between tillage tools and soil is of a primary interest to the design and use of these tools for soil manipulation. A computer simulation is conducted by developing a program using C ++ programming language to study effect of tool depth and width on angle of soil failure plane, soil cutting coefficients, soil resistance force and Power requirements in three-dimensional soil cutting. The results demonstrated that at 0.2 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.6°, 19.8, 49.54, 16.47 and 1.38 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 51.6°, 10.64, 22.05, 7.26 and 1.30 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 1.77 kN and 1.03 kW and they were shown by 0.04 m width while the highest values were 2.07 kN and 2.26 kW and they were demonstrated by 0.1 m width of tine. At 0.3 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.7°, 27.42, 72.54, 24.11 and 1.39 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 52.3°, 13.70, 31.23, 10.35 and 1.35 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 4.27 kN and 4.66 kW and they were shown by 0.04 m width while the highest values were 4.86 kN and 5.29 kW and they were demonstrated by 0.1 m width of tine. At 0.4 m tine depth the highest values of angle of soil failure plane, frictional coefficient, overburden coefficient, soil cohesion coefficient and soil adhesion coefficient were 52.8°, 35.04, 95.27, 31.73 and 1.39 respectively and they were recorded by 0.04 m tine width while the lowest values in same sequence were 52.5°, 16.75, 40.39, 13.40 and 1.37 and they were recorded by 0.1 m width. The lowest values of soil resistance force and power were 8.19 kN and 8.93 kW and they were shown by 0.04 m width while the highest values were 9.13 kN and 9.95 kW and they were demonstrated by 0.1 m width of tine. It was concluded that Angle of soil failure plane and soil cutting coefficients decreased as tine working depth and width increased. Soil resistance force and power increased as angle of soil failure plane and soil cutting coefficients decreased as tine working depth and width increased.

Theoretical Justification of Reducing Soil Adhesion to the Surfaces of the Excavator Working Body at Creation Underground Infrastructure

It is proposed method of passive cleaning of the excavator working body from adhering soil that practically does not require additional energy. Theoretical studies of the surface temperature effect of the working body on the stickiness of cohesive fine-grained soils of different fractions are made, on the basis of which the calculation is made, and temperature regimes required to prevent adhesion are defined. The proposed design is recommended to be implemented in all types of shovels to improve the operational performance and, as a consequence, reduce the cost of earthworks.

Earthworm epidermal mucus: Rheological behavior reveals drag-reducing characteristics in soil

Soil adhesion occurs on the surfaces of soil-tillage implements during use. This phenomenon increases energy consumption and decreases tillage quality. Nevertheless, earthworms can comfortably move in moist or adhesive soil, although with soil particles seldom sticking to bodies. The influence of earthworm movement on epidermal mucus provides perspective for the interpretation of the results on drag-reducing characteristics. The amino acid composition and rheological behavior of epidermal mucus samples from three earthworm ecological species were studied in the laboratory. These earthworm species were represented by Eisenia fetida, Aporrectodea trapezoides, and Amynthas pingi, which were collected from the Typic Hapludolls with loam textures. An electro-stimulation device was developed to extract and collect approximately 5g of mucus (field weight) from several individuals of 30g in total of each earthworm species. Mucus samples from the three earthworm species were found to contain 16 amino acids. Aspartic acid, glutamic acid, and valine were present in relatively high concentrations in all the samples. The rheological behavior of earthworm epidermal mucus was investigated via continuous shear, thixotropy, and oscillation tests. The apparent viscosity initially increased and then decreased with the increase in mucus shear rate. The thixotropic behavior was demonstrated as the apparent viscosity of epidermal mucus recovered gradually with the decrease in shear rate. Oscillatory tests showed that the viscoelastic behavior of epidermal mucus can be altered with changes in oscillation frequency. A five-layer interface contact model revealed that the apparent viscosity of mucus changes with earthworm movement, thereby reducing the soil adhesion and friction resistance toward the earthworm body surface. Overall, this study revealed the drag-reducing characteristics of earthworm epidermal mucus and inspired the development of some potential bionic applications with lubricating functions for soil-tillage implements.

Using dye tracer for visualizing roots impact on soil structure and soil porous system

AbstractPlants influence the water regime in soil by both water uptake and an uneven distribution of water infiltration at the soil surface. The latter process is more poorly studied, but it is well known that roots modify soil structure by enhancing aggregation and biopore production. This study used a dye tracer to visualize the impact of plants on water flow in the topsoil of a Greyic Phaeozem. Brilliant blue was ponded to 10 cm height in a 1 m × 1 m frame in the field immediately after harvest of winter wheat (Triticum aestivum L.). After complete infiltration, the staining patterns within the vertical and horizontal field-scale sections were studied. In addition, soil thin sections were made and micromorphological images were used to study soil structure and dye distribution at the microscale. The field-scale sections clearly documented uneven dye penetration into the soil surface, which was influenced by plant presence and in some cases by mechanical compaction of the soil surface. The micromorphological images showed that root activities compress soil and increases the bulk density near the roots (which could be also result of root water uptake and consequent soil adhesion). On the other hand in few cases a preferential flow along the roots was observed.

Effect of axial stiffness on soil nail forces

Currently used soil nail design methods normally ignore axial stiffness of soil nails and assume that nail–soil adhesion fully develops during construction of the soil nail wall, which would allow the use of conventional stability analysis with peak soil parameters for the newly excavated slopes. Although not fully consistent with the monitoring results for soil nails in working conditions, the resulting structures are proven by the accumulated practical experience for conventional geometry and conventional materials used in soil nail construction. This paper considers the effect of axial stiffness on the forces developing in soil nails, which affects the design of soil nails of lower stiffness, for example soil nails reinforced with fibre-reinforced polymer tendons, or nails of greater lengths. The use of fibre-reinforced polymers has considerable advantages in construction due to their light weight, ease of site preparation and high durability. However, their use is often deterred by their relatively low stiffness and lack of ductility. The paper discusses the methods by which negative effect of the use of soil nails of lower axial stiffness and ductility can be overcome in design.

Three-dimensional discrete element modelling (DEM) of tillage: Accounting for soil cohesion and adhesion

Recent studies have shown that the discrete element modelling (DEM) can effectively be used to model the soil-tool interaction if both an appropriate contact model and DEM parameters are used. Ucgul, M., Fielke J.M and Saunders, C. (2014a) Biosystems Engineering. 121: 105–117 showed that hysteretic spring contact model (HSCM) can give accurate predictions of draft and vertical forces for a range of sweep tillage tool geometries operating in a cohesionless soil. In this study a linear adhesion/cohesion model was integrated with the HSCM to model the cohesive behaviour of soil and its interaction with a tillage tool. The proposed contact model was validated with the direct shear tests performed and further validation was achieved via DEM simulation of the interaction between soil and tillage tool tests. The results showed that the suggested contact model can be used to predict both tillage draft and vertical tillage forces for varying speed, operating depth, moisture content and compaction levels. The results also showed that the DEM parameters determined in our earlier paper can be directly used in the suggested model without further re-calibration. It was observed that the soil bulk density has a significant effect on the predicted tillage forces and when the measured wet bulk density was used in the simulations a good correlation with measured forces was able to be achieved. Thus, the method presented has good potential to accurately model tillage forces in a range of soil and operating conditions.

INVESTIGATE A SIMPLE DESIGN FOR SWEET POTATO HARVESTING

The digging harvesting machine was modified and tested to perform the effect of harvesting speeds on harvesting qualities such as sweet potato lifting, un-lifting, damaged, un-damaged, soil adhesion on tuber surface and machine productivity. These indicators were evaluated under condition of medium at El Dakahlia Governorate (Belqas), Egyptian. A lot of experimental field were conducted on sweet potato harvesting under three different levels of separator length (450, 700 and 1200mm); reciprocated cam with link length of 180, 210 and 240 mm and three forward speeds (3.6;, 5.1 and 7.2km/h) under digging Nose share.. The obtained results concluded that the maximum value of sweet potato lifting efficiency was 97.14% recorded at 3.6 km/h harvesting speed and reciprocated cam with link length of 180mm. At reciprocated cam with link length of 180mm, increasing forward speed from 3.6 to 7.2 km/h increased the un-lifted of 2.74; 1.26 and 1.19 times at separator length of 450, 700 and 1200mm respectively. Generally, increasing harvesting speed increased sweet potato damage and decreased un-damage percentage. For example, at reciprocated cam with link length of 180mm, increasing forward speed from 3.6 to 7.2 km/h increased mechanical damage from 2.80 to 3.85% and decreased un-damage from 97.12 to 96.15% at separator length of 450mm. The harvesting forward speed strongly affected soil adhesion on sweet potato surface. By increasing forward speed from 3.6 to 7.2 km/h decreased soil adhesion on sweet potato surface under all treatments except at reciprocated cam with link length of 180mm.

Variation of limiting lateral soil pressure with depth for pile rows in clay

Pile group interaction effects on the lateral pile resistance are investigated for the case of a laterally loaded row of piles in clay. Both uniform undrained shear strength and linearly increasing with depth shear strength profiles are considered. Three-dimensional finite element analyses are presented, which are used to identify the predominant failure modes and to calculate the reduction in lateral resistance due to group effects. A limited number of two-dimensional analyses are also presented in order to examine the behaviour of very closely spaced piles. It is shown that, contrary to current practice, group effects vary with depth; they are insignificant close to the ground surface, increase to a maximum value at intermediate depths and finally reduce to a constant value at great depth. The effect of pile spacing and pile–soil adhesion are investigated and equations are developed for the calculation of a depth dependent reduction factor, which when multiplied by the limiting lateral pressure along a single pile, provides the corresponding variation of soil pressure along a pile in a pile row. This reduction factor is used to perform p–y analyses, which show that, due to this variation of group effects on the lateral soil pressures with depth, the overall group interaction effects depend on the pile length. Comparisons are also made with approaches used in practice that assume constant with depth reduction factors.

Effects of Bionic Geometric Structure Press Rollers on Reducing Rolling Resistance and Adhesion against Soil

Press roller is a commonly used tool for compacting soil to a suitable compactness. An ideal press roller should be able to ensure a low adhesion and rolling resistance in a suitable compaction. However, in tillage operation, the phenomenon of soil adhesion occurred widely when press roller worked. In this research, the ventral surface of dung beetles was taken as the bionic prototype and bionic ridged geometric structure press rollers were designed using ultra high molecular weight polyethylene material. Under the same testing conditions, press rollers with different geometrical details were conducted to examine the effect of ridge section diameter, ridge height to diameter ratio and the number of ridges along the circumference of the rollers on rolling resistance and soil adhesion. The results showed that the all bionic rollers exhibited lower adhesion than a conventional roller. While, only ridged bionic roller with suitable size could reduce rolling resistance. The bionic roller with the ridge diameter of 40 mm, dimensionless ratio of height to diameter of 0.5, the number of 12 indicated the lowest resistance in this work, 25 % lower than conventional roller.

The Role of Bionic Modifications in Reducing Adhesion and Draft of Agricultural and Earthmoving Machinery

Soil adheres to the surfaces of soil engaging components of earthmoving machinery and equipment. It has been pbserved that up to 50% of energy may be consumed in overcoming adhesion and friction of soil to the surfaces of soil engaging components of agricultural and earthmoving machinery. Surface morphology, chemical composition, elasticity, lubrication mechanism and electric osmosis play significant roles in reducing adhesion, friction and energy consumption of various equipment. Some of these techniques have very limited application in the practical field conditions because of the time and amount of fluid required to achieve the desired results. Whereas other techniques are effective in reducing adhesion and friction and improving work quality of these machines and equipment. This paper analyses the forces including the drafts of conventional and bionic bulldozing blades operating under identical conditions using mathematical modelling. The force analysis showed that both adhesion and friction play major role in reducing drafts of earrthmoving machinery. It is also worth stating that both the surface morphology and the construction materials play important role in reducing adhesion and friction of ground eganging components of earthmoving machinery.

Effect of loading direction on the ultimate lateral soil pressure of two piles in clay

Design equations are presented for the calculation of the ultimate lateral resistance of two-pile groups in clay under a general loading direction. Analytical upper bound solutions, numerical upper and lower bound limit analyses and displacement finite-element analyses are first presented for the case of two piles loaded parallel to the pile-to-pile axis. Displacement finite-element analyses are subsequently used to calculate the ultimate lateral resistance for different directions of pile displacement. The design equations that are proposed, based on the numerical study, take account of the effect of the pile spacing, the pile–soil adhesion and the displacement or the loading direction on the ultimate lateral resistance.

Undrained limiting lateral soil pressure on a row of piles

The displacement finite element, lower and upper bound finite element limit analysis and analytical upper bound plasticity methods are employed to investigate the undrained limiting lateral resistance of piles in a pile row. Numerical analyses and analytical calculations are presented for various pile spacings and pile–soil adhesion factors. The numerical results are shown to be in excellent agreement with each other and also with the theoretical upper bounds produced by the analytical upper bound calculations. Based on the numerical and analytical results, an empirical equation is proposed for the calculation of the ultimate undrained lateral bearing capacity factor. This equation is subsequently used to calculate p-multipliers applicable to the lower part of piles in pile rows, which are compared to multipliers available in the literature (that are constant with depth). The comparison shows significant differences, indicating that the amount of reduction in lateral resistance due to group effects is not constant with depth as routinely assumed in practice.

Modification of clay adhesion to improve tunnelling excavation

Mechanical tunnel driving by means of tunnel boring machines through clayey soils often leads to clogging problems which cause delays in tunnel construction and economic issues. Taking into account the diffuse double-layer theory, two very well-known clay formations, namely the Ypresian and Boom clays were investigated. Several geotechnical tests and a new adhesion test (cone pull-out test) were performed using water and solutions with different sodium chloride concentration as pore fluids. The results showed a reduction of the liquid limit for both clays when salt solutions were used instead of water. Undrained shear strength of the Ypresian clay progressively increased as the sodium chloride concentration of the pore fluid increased, whereas that of the Boom clay, which contains less smectite, was less sensitive to the chemical composition of the pore fluids. Cone pull-out tests, developed to detect the adhesive properties of clays, showed a drastic drop of clogging for the Ypresian clay when mixed with sodium chloride solutions within the entire consistency range studied, whereas in the case of Boom clay the variation was less evident and a clear effect was only observed at low consistencies. The results are promising for improving tunnelling excavation performance by adding sodium chloride solutions to avoid problems derived from adhesion of clayey soils.

Lateral bearing capacity of rigid piles near clay slopes

Analytical equations were derived to determine the undrained lateral bearing capacity of rigid piles in cohesive soil. Piles in level ground and piles placed at a distance from the crest of a slope were examined, taking account of the effect of the adhesion at the pile–soil interface. The derived analytical solutions were used to develop charts relating the lateral pile capacity to the pile length/diameter ratio, the pile–soil adhesion, the distance of the point of load application from the ground to the pile diameter ratio, the inclination of the slope and the distance of the pile from the crest of the slope to the pile diameter ratio. They were also used to derive a reduction factor which, when multiplied by the lateral bearing capacity for level ground, gives the bearing capacity of the same pile near a slope. In addition, a critical non-dimensional distance between the pile and the crest of the slope, at which the bearing capacity approaches that for a level ground, was determined. The bearing capacity charts obtained for level ground were compared to the classic Broms' charts and to others derived using several different lateral earth pressure distributions along the pile. Comparisons were also made between the results of the proposed method for piles near slopes and those obtained from charts based on upper bound calculations. Finally, the proposed new method was validated through a comparison with the results of a large number of pile load tests, in which a remarkable agreement was observed between the analytical results and the measurements.

Derivation of Quantitative Removal Efficiency of Protein Stain from K/S Value of Washing Test Fabric Soiled with Hemoglobin

We have improved a previous method for the preparation of hemoglobin-soiled fabrics in order to facilitate quantitative calculation of the efficiency with which protein stains can be removed from such materials. We then evaluated the sensitivity of surface reflectance as a method for stain quantification. Test fabrics were made by spotting a white fabric with a certain amount of hemoglobin solution and drying it. We observed a large difference between the percentage stain removal as measured by surface reflectance when compared with chemical analysis. Deformities in the surface of the soiled fabric caused by capillary action in the drying process likely contributed to this difference. Quantitative removal percentage could be predicted easily from the K/S values of test fabrics that were dry-heated without steam, although soil adhesion was too weak to evaluate the washing power of commercial detergent. Overall, we found that practical test fabrics with adequate soil adhesion properties can be prepared by adopting a steam heating process after dry heating.

친수 및 소수처리 PET직물의 고형오구의 세척성

The effect of hydrophilicity and hydrophobicity of PET fabric on the detergency of particulate soil were investigated as functions of the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. The detergency of the particulate soil was determined by the adhesion of particles to and their removal from fabric, the PET fabric and <TEX>${\alpha}-Fe_2O_3$</TEX> were used as textile materials and for the model of particulate soil, respectively. The hydrophilic and hydrophobic finish for PET fabric was treated with a polyester, silicone and fluorine organic compound of resin respectively. The adhesion of particulate soil to fabric treated with hydrophobic chemicals were slightly higher but its removal from fabric treated with hydrophobic chemicals was largely higher than fabric treated with a hydrophilic chemical regardless of solution conditions such as the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. Therefore, hydrophobic treatment for fabric had a more positive effect than the hydrophilic treatment on the detergency of particulate soil.

Effect of Temperature on Adhesion of Clay Soil to Steel

Effect of Temperature on Adhesion of Clay Soil to Steel Soil adhesion is one of the important factors in measuring the amount of energy consumption. In this paper, the effect of temperature on the amount of clay soil adhesion was investigated. The soil used in this research was saturated clay mud. In order to measure adhesion, a specific instrument was designed. The dimensions of the metal plate were 210x70x20 mm and its weight was 2.5 kgf. The metal plate alloy was st37. The adhesion was calculated from the difference between weight of water used for clearing the metal plate of the soil and the weight of the metal plate. Six levels of temperature from 5 to 30°c were applied. A refrigerator and an oven were used for getting the required temperature. The test was performed three times for each level. Results showed that an increase in temperature from 5 to 30°c decreases the soil adhesion. Three equations such as linear polynomial, exponential and quadratic polynomial correlated with the experimental data and the result showed that the quadratic polynomial model had the best correlation with experimental data.

Experimental Study on Bionic Screw Pile of Reducing Adhesion and Resistance

The surface of compound eye of ant was observed by using scanning electron microscopy technology. These characteristics on the surface were applied on cone of screw pile for preventing flood and rushing to deal with an emergency. Comparing experiments of piling were conducted before and after the bionic surface was made, and these experiments were conducted under three different soil environments, including soil among the Yellow River, the Yangtze River and the Pearl River. In the experiments, data of strain was tested and collected by dynamic strain gauge RA2300 style. The output was recorded on disc and later the data were processed by computer. The observation results showed that the compound eye of ant was made of a lot of small convex eyes. These small convex eyes were arranged in dense style. They had the characteristics of convex dome. The results of piling experiments showed that the bionic screw pile with bionic surface of cone produced better effect of reducing soil adhesion and resistance than the common screw pile with no bionic surface of cone.

Resistance reduction by bionic coupling of the earthworm lubrication function

Based on the biological coupling theory, the resistance reduction characteristic of the surface morphology and surface wettability of the earthworm were studied in this paper. The parameters of surface dorsal pore and corrugation were extracted. According to these parameters, the lubrication mechanism of the earthworm surface was analyzed. The distribution of the pores and surface morphology were designed and the bionic coupling samples were prepared. The positive pressure, lubricant flow rate and advancing velocity were selected as the experiment factors while the soil friction resistance as observed object. According to the obtained data of bionic coupling samples from the testing system of biologic signal for tiny soil adhesion test, the optimal samples from the bionic coupling resistance reduction tests were selected through the range analysis. Compared to the normal ones, the soil resistance of bionic coupling samples was reduced by 76.8%. This is of great significance and offers bright prospects for reducing energy loss in terrain mechanics.

Plant/soil concentration ratios for paired field and garden crops, with emphasis on iodine and the role of soil adhesion

In the effort to predict the risks associated with contaminated soils, considerable reliance is placed on plant/soil concentration ratio (CR) values measured at sites other than the contaminated site. This inevitably results in the need to extrapolate among the many soil and plant types. There are few studies that compare CR among plant types that encompass both field and garden crops. Here, CRs for 40 elements were measured for 25 crops from farm and garden sites chosen so the grain crops were in close proximity to the gardens. Special emphasis was placed on iodine (I) because data for this element are sparse. For many elements, there were consistent trends among CRs for the various crop types, with leafy crops > root crops ≥ fruit crops ≈ seed crops. Exceptions included CR values for As, K, Se and Zn which were highest in the seed crops. The correlation of CRs from one plant type to another was evident only when there was a wide range in soil concentrations. In comparing CRs between crop types, it became apparent that the relationships differed for the rare earth elements (REE), which also had very low CR values. The CRs for root and leafy crops of REE converged to a minimum value. This was attributed to soil adhesion, despite the samples being washed, and the average soil adhesion for root crops was 500 mg soil kg −1 dry plant and for leafy crops was 5 g kg −1. Across elements, the log CR was negatively correlated with log Kd (the soil solid/liquid partition coefficient), as expected. Although, this correlation is expected, measures of correlation coefficients suitable for stochastic risk assessment are not frequently reported. The results suggest that r ≈ −0.7 would be appropriate for risk assessment.