• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.539-545
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• 2010

The field plate test has a good potential for determining since it measures both plate pressure and settlement. The deformation modulus of rock mass is differently measured for status of structures. The values of deformation modulus are obtained from laboratory test (uniaxial and triaxial test) and field test (pressuremeter test). Plate load test should be conducted by different loading plate sizes for geological structure of rock mass and scale of structures. In this paper, large plate load tests were performed to predict of structure's behavior and evaluate the ultimate bearing capacity of the foundation on soft rock. Simultaneously, deformation modulus of rock mass was estimated by back analysis of stresses measured in field test under rock mass. Finally, we verified the validation of deformation modulus of rock mass through result of large plate load test and numerical simulation.

• Steel and Composite Structures
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• v.23 no.6
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• pp.623-631
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• 2017

Present paper deals with the temperature-dependent buckling analysis of sandwich nanocomposite plates resting on elastic medium subjected to magnetic field. The lamina layers are reinforced with carbon nanotubes (CNTs) as uniform and functionally graded (FG). The elastic medium is considered as orthotropic Pasternak foundation with considering the effects of thermal loading on the spring and shear constants of medium. Mixture rule is utilized for obtaining the effective material properties of each layer. Adopting the Reddy shear deformation plate theory, the governing equations are derived based on energy method and Hamilton's principle. The buckling load of the structure is calculated with the Navier's method for the simply supported sandwich nanocomposite plates. Parametric study is conducted on the combined effects of the volume percent and distribution types of the CNTs, temperature change, elastic medium, magnetic field and geometrical parameters of the plates on the buckling load of the sandwich structure. The results show that FGX distribution of the CNTs leads to higher stiffness and consequently higher buckling load. In addition, considering the magnetic field increases the buckling load of the sandwich nanocomposite plate.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.67-79
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• 2005

The field plate load test has a good potential for determining modulus since it measures both plate pressure and settlement. Conventionally the modulus has been assumed to be a constant secant value defined from the settlement of the plate at a given load intensity. A constant modulus (modulus of subgrade reaction, k), however, may not be a representative value of subgrade soil under working load. Field strain(o. stress)-dependent modulus characteristics of subgrade soils, at relatively low to intermediate strains, are important in the pavement design. In this study, the field strain dependent moduli of subgrade soils were obtained using cyclic plate load test. Testing procedure and data reduction method are proposed. The field crosshole and laboratory resonant column tests were also performed to determine field nonlinear modulus at $0.001\%\;to\;0.1\%$ strains, and the modulus values and nonlinear trends are compared to those obtained by cyclic plate load tests. Both modulus values match relatively well when the different state of stress between two tests was considered, and the applicability of field cyclic plate load test for determining nonlinear modulus values of subgrade soils is verified.

• Advances in nano research
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• v.7 no.6
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• pp.405-417
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• 2019

This research is devoted to study post-buckling analysis of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) micro plate with cut out subjected to magnetic field and resting on elastic medium. The basic formulation of plate is based on first order shear deformation theory (FSDT) and the material properties of FG-CNTRCs are presumed to be changed through the thickness direction, and are assumed based on rule of mixture; moreover, nonlocal Eringen's theory is applied to consider the size-dependent effect. It is considered that the system is embedded in elastic medium and subjected to longitudinal magnetic field. Energy approach, domain decomposition and Rayleigh-Ritz methods in conjunction with Newton-Raphson iterative technique are employed to trace the post-buckling paths of FG-CNTRC micro cut out plate. The influence of some important parameters such as small scale effect, cut out dimension, different types of FG distributions of CNTs, volume fraction of CNTs, aspect ratio of plate, magnitude of magnetic field, elastic medium and biaxial load on the post-buckling behavior of system are calculated. With respect to results, it is concluded that the aspect ratio and length of square cut out have negative effect on post-buckling response of micro composite plate. Furthermore, existence of CNTs in system causes improvement in the post-buckling behavior of plate and different distributions of CNTs in plate have diverse response. Meanwhile, nonlocal parameter and biaxial compression load on the plate has negative effect on post-buckling response. In addition, imposing magnetic field increases the post-buckling load of the microstructure.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.44-52
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• 2007

Recently, oystershell wastes cause serious environmental problem and the need for the researches on the recycling of oystershell have been increased and various methods are already in operation. Field plate bearing tests and numerical analysis were performed to investigate the bearing capacity of oystershell filled geotextile gabion which utilized the waste oystershell at the coastal oyster farm site. The waste oystershell mixed soil specimens were prepared for the laboratory test and field test in terms of varying blending ratio of granite soil and oystershell. Based on the cyclic plate load test results, the spring constant, subgrade modulus of ground, and the reinforcing parameters were determined. The field plate load test results indicate that the bearing capacity of the soil ground with the oystershell mixed ratio of 20% is greater than that of the original ground. Two-dimensional numerical analysis was evaluated the expected deformation in the given conditions. Analysis results show a similar characteristics on bearing capacity with the results of the field plate load test. These findings suggest that the oystershells are very promising construction materials for landfill and earth embankment in coastal area.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.782-791
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• 2009

This study was carried out the laboratory tests and field plate load test in order to evaluate the reinforcement effect of geocell for road construction. The geocell-reinforced subgrade shows the increment of cohesion and friction angle with comprison of non-reinforced subgrade. In addition, the field plate load test was performed on the geocell-reinforced subgrade to estimate the bearing capacity of soil. The direct shear test was conducted with utilizing a large-scale shear box to evaluate the internal soil friction angle with geocell reinforcement. The number of cells in the geocell system is varied to investigate the effect of soil reinforcement. The theoretical bearing capacity of subgrade soil with and without geocell reinforcement was estimated by using the soil internal friction angle. The field plate load tests were also conducted to estimate the bearing capacity with geocell reinforcement. It is found out that the bearing capacity of geocell-reinforced subgrade gives 2 times higher value than that of unreinforced subgrade soil. In the future, the reinforcement effect of the geocell rigidity and load-balancing effect of the geocells should be evaluated.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.861-866
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• 1998

This study is numerical procedure of strengthening capacity in a field structure and compare analysis data with test data. Recently, many strengthening methods are developed and used to rehabilitate existing structure. However, both theoretical background and applying techniques are not established yet. One of the most popular method is plate bonding method using either steel plate or carbon plate. This theoretical background and applying techniques are very important and those applications are differed when applied in field strengthening cases. Also depending on the analysis out come, displacement increased based n the condition of members while reaching ultimate load or failure load.

• Earthquakes and Structures
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• v.15 no.3
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• pp.285-294
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• 2018

In this study, nonlinear dynamic response of a concrete plate retrofit with Aluminium oxide ($Al_2O_3$) under seismic load and magnetic field is investigated. The plate is a composite reinforced by Aluminium oxide with characteristics of the equivalent composite being determined using Mori-Tanka model considering agglomeration effect. The plate is simulated with higher order shear deformation plate model. Employing nonlinear strains-displacements, stress-strain, the energy equations of column was obtained and using Hamilton's principal, the governing equations were derived. Differential quadrature method (DQM) in conjunction with Newark method is applied for obtaining the dynamic response of structure. The influences of magnetic field, volume percent of nanoparticles, geometrical parameters of column, agglomeration and boundary conditions on the dynamic response were investigated. Results showed that with increasing volume percent of nanoparticles, the dynamic deflection decreases.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.751-763
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• 2017

This article deals with the buckling behaviour of multilayered magneto-electro-elastic (MEE) plate subjected to uniaxial and biaxial compressive (in-plane) loads. The constitutive equations of MEE material are used to derive a finite element (FE) formulation involving the coupling between electric, magnetic and elastic fields. The displacement field corresponding to first order shear deformation theory (FSDT) has been employed. The in-plane stress distribution within the MEE plate existing due to the enacted force is considered to be equivalent to the applied in-plane compressive load in the pre-buckling range. The same stress distribution is used to derive the potential energy functional. The non-dimensional critical buckling load is accomplished from the solution of allied linear eigenvalue problem. Influence of stacking sequence, span to thickness ratio, aspect ratio, load factor and boundary condition on critical buckling load and their corresponding mode shape is investigated. In addition, static deflection of MEE plate under the sinusoidal and the uniformly distributed load has been studied for different stacking sequences and boundary conditions.

• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.5-17
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• 2011

Sampling disturbance can often introduce considerable errors in the laboratory estimation of geotechnical properties of soils. Accordingly, it causes inappropriative results in analysing field behavior. Therefore, a screw plate load test, one of in-situ test technique, is developed in this study, because in-situ testing techniques have advantages for the estimation of reliable geotechnical parameters. The screw plate load test, which was modified from the plate load test, conducts an experiment underneath ground by inserting a spiral type of auger screw. In this study, the structure and characteristics of the screw plate load test device are introduced in detail and the reliability of the device is examined through the analysis of the laboratory test results.