• Journal of the Korean Geosynthetics Society
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• v.1 no.1
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• pp.53-61
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• 2002

Even though a lot of laboratory and field tests for asphalt pavements using geosynthetics have been conducted recently, any rational and systematic analysis for the economic efficiency of the asphalt pavement systems reinforced by using geosynthetics has not been proposed yet. In this study, the economic analysis considering the traffic characteristics for the glass fiber sheet reinforced asphalt pavement was performed using the Life Cycle Cost Analysis(LCCA) which is commonly used for the economic analysis technique. The economic efficiency for the glass fiber sheet reinforcement and the traffic characteristics was examined by applying the test results from the literature review to the economic analysis model.

• Geotechnical Engineering
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• v.4 no.1
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• pp.37-48
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• 1988

This is a part of research projects to investigate the several significant statistical correlati- onships among the various physical and engineering properties of alluvial clayey deposits in the estuary area of the great fixe rivers through the South-West coastal districts where are expected to be developed as large ingustrial site or agricultual development projects. As a first trial, the statistical analyses through computer programs were carried out using the results of laboratory and field tests of 227 soil samples from the Seum-Jin river area. When the initial void ratio which plays crucial role to the settlement of foundation is more than 2.5, the compression indices of soil samples are remarkably scattered, but these indices, which are formulated as a general expression, tend to increase as increasing the clay content, liquid limit, plastic limit and initial void ratio.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.5-13
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• 2008

To identify the reclamation history formed by top dredged soil reclamation layer over the original ground, various field tests and laboratory tests were conducted. Especially when the original ground was not completely consolidated, CPTu test was carried out to calculate rational settlement due to the banking load. CPTu test results showed that the degree of consolidation of weak clay ground by dredged reclamation was on average 80%. As the research area was not completely consolidated by dredged reclamation in the past, the consolidation settlement should account for the residual settlement (20%) in the case of additional banking load. When the degree of consolidation of the original ground was not taken into account, the residual consolidation was expected in excessive settlement (up to 20%) and in such case PBD (Plastic Board Drain) was not effective in obtaining desired degree of consolidation.

• Journal of the Society of Disaster Information
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• v.3 no.2
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• pp.147-169
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• 2007

This study investigates the reinforcing effects of the Multi-bar Spring nails with respect to the conventional Soil-nails in artificial slopes. Based on wide experience related to design and construction, soil nails have been widely applied to reinforce slope in the world. Multi-bar spring nails are one of the improved soil nailing methods. These method maximizes bending, shearing, pull-out resistance for those multi-nails, not unit nail, that are inserted in the borehole using special spacer at regular intervals. In addition, because cutting plane is confined effect resulting from a pressured plate at the end of the nails with compression spring equipment, slope stability is secured using MS-nailing method. Analyzing bending, pull-out, shearing condition of MS-nail, it was examined throughly elastic region, load transfer capacity, reinforcing effect on cutting plate of MS-nails. In addition, Pilot and laboratory tests, numerical analysis were carried out to verify the superiority of MS-nailing method. In case, MS nailing method is applied to reinforce artificial slope, it was analyzed that bending, pull-out, shearing resistance was increased more than existing nailing method was applied. In this study, it was shown that surface failure was more or less prevented using MS-nailing method, confining effect on cutting plane using spring stuck to flexible equipment.

• Journal of Korea Water Resources Association
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• v.44 no.9
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• pp.731-740
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• 2011

An acoustic velocity profiler is developed, which is able to be used for open-channel flow measurement. It measures flow velocity based Doppler effect on acoustic signals, which is estimated by using pulse repetition frequency technique. Laboratory and field tests were made to verify velocity measuring performance of the developed device. It is confirmed that the acoustic velocity profiler can normally measure vertical velocity profile in the range above 0.1 m from the bottom and has equivalent performance to commercial acoustic velocity measuring devices.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.629-633
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• 2008

Recently, there has been great interest in the application of short-range wireless communication system. In this paper, the miniaturized FM transmitter with low power is developed, and laboratory tests have been carried out. The FM transmitter uses FM radio waves to send sound from any system (MP3, PMP, PDA, MP3 Phone et.) to any nearby radio or stereo system. The transmitter is designed with $2.6cm{\times}2.6cm{\times}2.6cm$ system size. The operating voltage is 3.7 V and used the built-in storage battery. The system can use continuously during 7 hour with once charging. The transmission frequency can select one of 88.1 MHz, 88.3 MHz, or 88.5 MHz in compliance with utility condition. The channel separation ability is 40 dB. The operating temperature is $-10{\sim}+85^{\circ}C$, which use in the industry environment. Consequently, this system sis used conveniently with short distance information transmitter system at the industry field.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.2
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• pp.29-34
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• 2009

A series of laboratory model tests and numerical analysis is performed to analyze characteristics of desalination and to predict a period of desalination for subsurface saturated soil in Saemanguem reclaimed area. The results show that quantity of desalination is small as salinity of water is increased. On the contrary, quantity of desalination is increased as salinity of soil is high. In order to decrease the salinity to 10 % of initial salinity of soil at depth of 2 m, it takes 11 years to desalinate the soil 50 m away from drainage ditch. For soil at depth of 1.5 m only 1 year to desalinate the soil near drainage ditch. Also, water head of 80 cm is required to desalinate to 10 % of initial salinity for 60 cm thick soil. Because the following results is based upon the Saemangeum soil, an application of this result for another field will be cautious. More research will be required on this matter.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.293-299
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• 2023

The Wide-Angle Polarimetric Camera (PolCam) is installed on the Korea's lunar orbiter, Danuri, which launched on August 5, 2022. The mission objectives of PolCam are to construct photometric maps at a wavelength of 336 nm and polarization maps at 461 and 748 nm, with a phase angle range of 0°-135° and a spatial resolution of less than 100 m. PolCam is an imager using the push-broom method and has two cameras, Cam 1 and Cam 2, with a viewing angle of 45° to the right and left of the spacecraft's direction of orbit. We conducted performance tests in a laboratory setting before installing PolCam's flight model on the spacecraft. We analyzed the CCD's dark current, flat-field frame, spot size, and light flux. The dark current was obtained during thermal / vacuum test with various temperatures and the flat-field frame data was also obtained with an integrating sphere and tungsten light bulb. We describe the calibration method and results in this study.

• Geomechanics and Engineering
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• v.7 no.5
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• pp.495-524
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• 2014

To investigate the soil-pile interactive performance under lateral loads, a set of laboratory model tests was conducted on remoulded test bed of soft clay and medium dense sand. Then, a simplified boundary element analysis had been carried out assuming floating pile. In case of soft clay, it has been observed that lateral loads on piles can initiate the formation of a gap, soil heave and the tension crack in the vicinity of the soil surface and the interface, whereas in medium dense sand, a semi-elliptical depression zone can develop. Comparison of test and boundary element results indicates the accuracy of the solution developed. However, in the boundary element analysis, the possible shear stresses likely to be developed at the interface are ignored in order to simplify the existing complex equations. Moreover, it is unable to capture the influence of base restraint in case of a socketed pile. To bridge up this gap and to study the influence of the initial stress state and interface parameters, a field based case-study of laterally-loaded pile in layered soil with socketed tip is explored and modelled using the finite element method. The results of the model have been verified against known field measurements from a case-study. Parametric studies have been conducted to investigate the influence of the coefficient of lateral earth pressure and the interface strength reduction factor on the results of the model.

• Geotechnical Engineering
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• v.14 no.5
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• pp.29-38
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• 1998

The purpose of this research is to develop an amended clay liner by utilizing waste lime produced as a by-product in chemical industries. Waste lime contains various kinds of organics which affect the permeability, compactability, and unconfined compressive strengths of soil. The geotechnical engineering properties of waste were improved by adding other materials so that they might meet the EPA requirement of clay liner. Granite weathered soil, which is abundant in Korea and can be obtained easily in the field. was used as a primary additive to improve geotechnical engineering properties of waste lime. Various kinds of laboratory tests related to geotecnnical engineering properties, required to evaluate the design criteria for the clay liner in the solid waste landfill. were carried out by changing miRing ratio of waste lime with additive. According to the laboratory test results, in order to obtain the appropriate amended clay liner. the effective miffing ratio of waste lime in granite weathered soil was proved to be about 20~30%.