Soil Reaction Forces Research Articles

Development a Device for Measuring Soil Mechanical Properties

In tillage operations to know soil reaction force on the tools working inside soil and under agricultural vehicle tires, soil mechanical parameters should be determined. Measurement and determination of soil mechanical parameters will be helpful for optimum designing of tillage tools to decrease required energy. An experimental device was developed at the University of Mohaghegh Ardabil which is able to conduct three soil mechanics tests of sinkage, penetration and shear, by which soil cohesion, internal friction, stiffness, soil constant and strength were determined. For sinkage and penetration tests an electromotor power was translated to a rectangle plate via a translating system such that moves plate or cone penetrometer vertically and forces it in soil. While fore shear test it moves shear plate horizontally as plate shears the soil. Required forces for sinkage, penetration and shearing were measured by loadcell and vertical and horizontal displacements were measure using linear potentiometer (LVDT). All data logged to a loptop via a data logger. All mentioned parameters for a type of soil were computed desirably related tests.

Calculation of Settlement of Composite Foundation with Rigid Piles under Flexible Ground

According to the character of the interaction of the pile, soil and cushion in composite foundation by fitting the vertical relative displacement distribution function of pile-soil element and introducing an elastic-plastic load transfer model, and deformation form of the pile-soil relative displacement, friction variation of pile, and pile-side soil reaction force model were simplified to a certain degree, and a basic differential equation of settlement calculation of the rigid pile composite foundation was established with consideration of both upward and downward penetration displacements of piles and the coordination of deformation of neutral point and the pile-soil interface. Then, a new method of calculating the settlement of the rigid pile composite foundation considering the interaction of pile-soil-cushion system was developed. At last, this new method was applied to the analysis of a model experiment and a project example, and the results show that (1) there exist great difference between the deformation mode and pile-soil stress ratio of rigid pile composite foundation under flexible ground and those under rigid ground; (2) the calculated results are close to the measured values. This method can reduce the calculation and provide a reference for the settlement calculation of rigid pile composite foundation.

Características cinéticas durante a marcha de um músico com e sem o transporte de seu instrumento

The integrity of the locomotor system can be compromised by the transport of certain objects, especially when done in an inadequate manner. Due to their weight and size, the transport of musical instruments can contribute to body dysfunctions in musicians who frequently have to carry their instruments, influencing balance and body posture. Thus, the soil reaction force was investigated during the gait of a musician carrying or not his instrument. Two AMTI (Advanced Mechanical Technologies, Inc.) platforms were used for kinetic data acquisition. A total of 40 measurements were obtained for gait and balance: 20 without carrying the instrument and 20 while carrying the instrument. The t test showed significant differences between the two situations for all variables analyzed. The results suggest that the locomotor system suffers alterations when carrying any kind of load, as was the case here in which the subject carried 7.75% of his own weight.

Prediction of Soil Reaction Force at Specific Positions on a Moldboard Plow Surface

Prediction of Soil Reaction Force at Specific Positions on a Moldboard Plow Surface

휠로더 굴착 자동화를 위한 버킷 부하특성 연구

The front end wheel loader is widely used for the loading of materials in mining and construction fields. It has repetitive digging, loading and dumping procedures. The bucket is subjected to large resistance force from the soil during scooping. We considered the soil reaction force characteristics from scooping procedure, the protection by overload and automatic scooping mode algorithm. The main topic of this paper is the analysis of the soil reaction force characteristics. The analysis of soil mechanics is carried out and the developed soil model is verified by experimental results from the simplified experimental equipment. A simplified model of the soil shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. In the future, this model will be used for the generation of an appropriate path for the wheel loader automation.

Interpreting the behavior of laterally loaded drilled shaft from measured deflection data

AbstractThe drilled shafts have been widely used to support lateral loads (active load case) or as a means to stabilize an unstable slope (passive load case) due to their large lateral load resistance and structural capacity for shear and bending moments. However, there is a need to develop an analytical procedure that can use the actual measured deflection data of a drilled shaft subject to either active or passive load case to interpret the soil‐drilled shaft interaction behavior. The mathematical formulation and the accompanied numerical procedure based on the principle of superposition were developed in this paper to allow for deducing the relevant soil‐drilled shaft interaction behavior under the applied lateral load (i.e. net soil reaction force on the drilled shaft, the shear and bending moment in the shaft) from the measured deflection data. Both compatibility and force equilibrium conditions were utilized in formulating the mathematical equations for common single drilled shaft boundary conditions (free head and fixed bottom). The current application is limited to small deformation to meet the requirement that the drilled shaft responds in a linear elastic range. A total of three theoretical cases, along with two actual field cases, were used to demonstrate the validity of the proposed method and its engineering applications. Copyright © 2009 John Wiley & Sons, Ltd.

Aplikasi Pengukuran Tahanan Tanah Terhadap Penekanan Plat Dalam Penentuan Parameter Desain Roda Besi Bersirip

Plat penetration resistance on paddy soil was measured for determination of a lug wheel designparameters. A penetrometer equipped with plat tips (three plat sizes) was used for soil penetrationmeasurement at 30o, 45o, 60o, 75o and 90o penetratiron angle, at the depth of 2.5 cm, 5 cm, 7.5 cm, 10 cm,12.5 cm, 15 cm, 17.5 cm dan 20 cm. The results showed that using plat inclination angle of 45o, producedhighest horizontal and vertical soil reaction forces. In the paddy soil with a deeper mud layer condition,soil reaction forces tended to significantly increase at 0-10 cm depth and at 15-20 cm depth. The soilreaction force at 15-20 cm depth at 90o penetration angle was 60 kPa. For the location, the optimum lugwheel design parameters were: 14 lugs, 8 cm lug height, 35 cm lug width, and 85 cm wheel diameter. Fora shallower mud layer paddy soil, the soil resistance significantly increased at 6-20 cm depth. Penetrationresistance at 15-20 cm depth at 90o penetration angle was higher than 90 kPa. The optimum lug wheeldesign parameters were: 14 lugs, 10 cm lug height, 35 cm lug width, and 85 cm wheel diameter.Keywords : paddy soil, plat penetration, soil resistance, lug wheel, designDiterima: 25 Pebruari 2009; Disetujui: 12 Juni 2009

Kinetic characteristics of the gait of a musician carrying or not his instrument

The integrity of the locomotor system can be compromised by the transport of certain objects, especially when done in an inadequate manner. Due to their weight and size, the transport of musical instruments can contribute to body dysfunctions in musicians who frequently have to carry their instruments, influencing balance and body posture. Thus, the soil reaction force was investigated during the gait of a musician carrying or not his instrument. Two AMTI (Advanced Mechanical Technologies, Inc.) platforms were used for kinetic data acquisition. A total of 40 measurements were obtained for gait and balance: 20 without carrying the instrument and 20 while carrying the instrument. The t test showed significant differences between the two situations for all variables analyzed. The results suggest that the locomotor system suffers alterations when carrying any kind of load, as was the case here in which the subject carried 7.75% of his own weight.

Simulation of front end loader bucket–soil interaction using discrete element method

AbstractThe design of earthmoving equipment requires reliable estimates of resisting forces from the soil or rock to be manipulated. A series of discrete element simulations with polyhedral particles designed to replicate a series of bucket–soil interaction experiments are presented. The experiments involve manipulation of a pile of gravel, consisting of angular and sub‐rounded particles, with a prototype of a front end loader bucket. The geometry of the soil pile and the trajectory of the bucket from each experiment are simulated using discrete element method (DEM). A single set of DEM model properties, including inter‐particle contact friction angle estimated from the initial configuration of the soil pile prior to the start of the experiments, are used for all simulations. The total soil reaction forces acting on the bucket in both horizontal and vertical directions are calculated from each simulation and are compared to measured forces from the corresponding experiment. The results show both qualitative and quantitative agreement between simulations with polyhedral particles and experiments with angular and sub‐rounded particles. The major source of discrepancy is attributed to the large particle sizes in the simulation compared to the experiments. Using smaller particles improves the results and provides a better match with the experiments. Other sources of discrepancy are also discussed. The simulations demonstrate that DEM with polyhedral particles can be used to reliably simulate bucket–soil interaction and to estimate force feedback into earthmoving equipment. Copyright © 2007 John Wiley & Sons, Ltd.

Projeto de um cortador de base para colhedora de cana-de-açúcar utilizando otimização matemática

Um cortador de base representado por um mecanismo de quatro barras foi desenvolvido utilizando-se do programa Autocad. Suas partes constituintes foram pré-dimensionadas em função das características operacionais de uma colhedora de cana-de-açúcar em sistema de cana crua e inteira, colhendo uma linha de cana por passada. A força normal de reação do perfil no ponto de contato foi determinada por meio da análise dinâmica, sendo as equações de equilíbrio dinâmico baseadas nas leis de Newton-Euler. O processo de otimização teve como objetivo minimizar a força normal de reação do solo, submetida a restrições de posição, trajetória, comprimento das barras, constante da mola e da força normal. Implementou-se o Algoritmo de Programação Quadrática Seqüencial - SQP do módulo de otimização do programa computacional Matlab. Os resultados mostraram melhora significativa no desempenho de flutuação do mecanismo, representada pela força normal de reação do perfil, a qual foi reduzida de 4.250,33 para 237,13 N. Posteriormente, outras variáveis foram incorporadas ao mecanismo otimizado e um segundo processo de otimização foi implementado.

Nonlinear Analysis of Laterally LoadedRock-Socketed Shafts

In this paper, a nonlinear continuum method is developed to predict the load-displacement response of drilled shafts under lateral loading. The method can consider drilled shafts in a continuum consisting of a soil layer overlying a rock mass layer. The deformation modulus of the soil is assumed to vary linearly with depth, and the deformation modulus of the rock mass is assumed to vary linearly with depth and then to stay constant below the shaft tip. The effect of soil and/or rock mass yielding on the behavior of shafts is considered by assuming that the soil and/or rock mass behaves linearly elastically at small strain levels and yields when the soil and/or rock mass reaction force p (force/length) exceeds the ultimate resistance pult (force/length). For the calculation of the ultimate resistance pult of the soil, methods that are available in the literature are used. To calculate the ultimate resistance pult of the rock mass, a method based on the Hoek-Brown strength criterion is proposed. The propose...

Theoretical analysis of soil reaction on a lug of the movable lug cage wheel

The measurement of soil reaction forces on a lug of a movable lug cage wheel was carried out in a soil bin. To elucidate the experimental results, a theoretical analysis of soil reaction forces on the lug of the movable lug cage wheel was made by using an analysis of the lug trajectory and a modified theory in soil–vehicle mechanics. The existing theory was modified and adjusted by considering the actual lug trajectory and the soil trench made by the preceding lug. The results showed that the theoretical analysis gave a good representation of the reaction forces measured experimentally. The higher pull and lift forces of the movable lug cage wheel compared with those of the fixed lug wheel was supported by the theoretical analysis. Although the theoretical representation of soil reaction forces should be improved by further works, it is sufficiently accurate to estimate the performance of the movable lug cage wheels by the proposed theory.

Experimental analysis of soil reaction on a lug of a movable lug wheel

A movable lug wheel was tested in a soil bin test apparatus to determine its traction performance and to measure the soil reaction forces on its lugs. Similar tests were also conducted using a fixed lug wheel. The effects of the lug motion pattern, lug spacing and horizontal load on pull and lift forces were studied. From the experiments it is confirmed that the movable action of the lug plate could generate superior pull and lift forces in comparison with the fixed lug wheel. Among the test wheels, lug motion pattern-2 generated the highest pull and lift forces. Within the range of the test conditions, there was no significant difference in pull and lift forces of the lug plate between the test lug wheels with 12 lugs and 15 lugs at the same level of horizontal and vertical loads. The increase of horizontal load up to 200 N generally increased the pull force and generated smaller rolling resistance before the lug left the soil, but did not increase the lift force significantly. The patterns of pull force, lift force and drawbar pull generated under a constant slip were slightly different from those under a constant horizontal load. Finally, the results were also elucidated by their actual lug trajectories in soil.

The Characteristics of Soil Reaction Forces on a Single Movable Lug

In order to understand clearly the characteristics of the soil reaction forces on a single movable lug, the resultant of measured soil reaction forces was determined and presented along with its position on the lug plate. The resultant of soil reaction forces acting on the movable lug increased gradually and reached the maximum value when the lug was on about its lowest position in the soil, then it decreased without offering any downward resistance to the lug till the lug left the soil. The maximum resultant force of the movable lug was higher than that of a fixed lug. The point of action of the resultant force on the movable lug shifted in a similar way in all test cases, that is, it moves to the center of the lug from the outer tip until it reaches the position where it becomes the maximum, then it moves to the outer tip till the lug leaves the soil. The inclination angle of the resultant force increased with the decrease of lug inclination angle. The bigger lug sinkage of the movable lug produced bigger soil reaction forces and shifted the point of action of the resultant force from the tip part to the central part of the lug. However, there was no significant effect of the lug sinkage on the direction of the resultant force. The increase in lug slippage from 25% to 50% brought bigger soil reaction forces on the movable lug, but did not influence the direction and point of action of the resultant force.

The characteristics of soil reaction forces on a single movable lug

In order to understand clearly the characteristics of the soil reaction forces on a single movable lug, the resultant of measured soil reaction forces was determined and presented along with its position on the lug plate. The resultant of soil reaction forces acting on the movable lug increased gradually and reached the maximum value when the lug was on about its lowest position in the soil, then it decreased without offering any downward resistance to the lug till the lug left the soil. The maximum resultant force of the movable lug was higher than that of a fixed lug. The point of action of the resultant force on the movable lug shifted in a similar way in all test cases, that is, it moves to the center of the lug from the outer tip until it reaches the position where it becomes the maximum, then it moves to the outer tip till the lug leaves the soil. The inclination angle of the resultant force increased with the decrease of lug inclination angle. The bigger lug sinkage of the movable lug produced bigger soil reaction forces and shifted the point of action of the resultant force from the tip part to the central part of the lug. However, there was no significant effect of the lug sinkage on the direction of the resultant force. The increase in lug slippage from 25% to 50% brought bigger soil reaction forces on the movable lug, but did not influence the direction and point of action of the resultant force.

Measurement of soil reaction forces on a single movable lug

In order to clarify characteristics of a new mechanism called a movable lug, a model of a single movable lug equipped with an L-shaped force transducer has been developed. The soil reaction forces (normal and tangential) on a flat single movable lug, a curved single movable lug and a fixed lug were measured on wet sandy loam soil in the laboratory soil bin test. These measured forces then were converted to lug pull and lift forces. The pull and lift forces obtained by the flat movable lug with 45° lug inclination angle and the curved movable lug were higher than those of the fixed lug. It was observed that the lift force of the fixed lug achieved its peak and dropped earlier than those of the movable lugs. However, the peaks of pull and lift forces of the flat and curved movable lugs were almost the same. The flat movable lug with 45° lug inclination angle generated a slightly higher peak of pull force than those with 30° and 60° lug inclination angles. However, the higher lug inclination angle produced, the lower peak of lift force. It was observed that the pull and lift forces increased as the sinkage increased. In contrast to the flat movable lug with 45° lug inclination angle, the curved movable lug produced greater lift force especially at high sinkage. The increase in lug slip from 5% to 25 and 50% caused an increase in the peaks of pull and lift forces. The soil moisture content affected the lug forces significantly.

Reactive Soil Pressures along Pile in Frozen Sand

A multistage, lateral, pile‐load creep test is carried out in a frozen sand maintained at -3°C. The pile is a tubular pipe, 150 mm square and 1,800 mm long. A series of plate load cells is mounted along the primary bearing face of the pile. Application of lateral loads of 35, 65, and 115 kN result in attenuating creep, whereas a lateral load of 145 kN leads to accelerating creep. The immediate components of pile displacement increase approximately linearly with applied load, while the creep components increase exponentially. Generally, the soil reaction forces near the ground surface decrease as the result of pile creep, and those further down the pile increase. Moduli of horizontal subgrade reaction computed on the basis of the measured soil reaction forces and the pile displacement are found to vary with applied pressure and creep. Magnitudes based on immediate displacements range from 1 to 7.5GN/m3, while those based on total displacements range from 0.3 to 2GN/m3.

Prediction of soil reaction forces on a moldboard plow surface

Abstract Using mathematical models, approximate trajectories of soil furrow subslices were determined and the forces occurring on the moldboard surface were calculated. The various components of the normal force along the trajectory line of the middle section of the furrow slice were analysed in relation to the velocity of plowing operation and the curvature of the path. The soil reaction forces encountered by the share portion of the plow were also determined by a model which used the method of trial wedges to determine the angle of the failure surface with the horizontal. The sum of the calculated forces was compared with that obtained by actual plowing experiments performed in the laboratory.

A model to determine the trajectory of soil motion on a moldbroad plow surface

A mathematical model was developed to determine the soil trajectory of motion on the moldboard plow surface. With the use of the model, trajectory lines of soil particle travel were calculated based on the shape of the moldboard plow surface. Also, with the use of the values of soil properties, soil-metal coefficient of friction, the travel speed of plow and the soil modulus of elasticity, equations of forces were solved for equilibrium condition of the furrow slice passing over the moldboard surface. The use of the model can be xtended to the approximation of the soil reaction forces occurring the plowing operation. Laboratory experiments were conducted to verify the validity of the model. the moldboard shape factors used were derived from the coordinates of points describing the contours of the plow surface as measured by a profilograph.

Factors Affecting Treader Soil Reaction Forces

ABSTRACT Soil reaction forces for three treader designs were measured in the field. The treaders were tested at three operating depths, four forward velocities and seven gang angles. Treader design, operating depth and treader gang angle significantly affected draft, side draft and vertical force. Draft, side draft and vertical force were linearly proportional to operating depth, trigonometric transformations of gang angle, cone index, and inversely proportional to the peripheral velocity squared. Prediction equations were developed relating reaction forces to depth, gang angle, cone index and peripheral velocity.