• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.23-29
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• 2009

A sand-cone method is commonly used to determine the density of the compacted soils. This method uses a calibration container to determine the bulk-density of the sand for use in the test. The density of the test or compacted soil is computed on the assumption that the calibration container has approximately the same size or volume and allows the sand to fall approximately the same height as a test hole in the field. However, in most cases the size or shape of test hole is not exactly the same as the calibration container. There is certain discrepancy between sand particle settlement or arrangement in the laboratory calibration and in the field testing, which may cause an erroneous determination of in-situ density. The sand filling process is simulated in the laboratory and its effect on the determination of density is investigated. Artificially-made holes with different heights and bottom shapes are prepared to simulate various shapes of the test hole in the field. The sands with different gradations are used in the testing to examine how sand grain size influences the determination of density in the field.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.9-17
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• 2017

In this study, the field density test was conducted as a volume conversion factor for the design of the excavation soil of the blasting rock. As a result of the field density test, the average volume conversion factor of rock was 1.001, which was smaller than the volume conversion factor of weathered rock 1.1. In the case of rock filled soil, the causes of the increase and decrease of the volume of the soil are provided by various phenomena. However, the specific techniques such as investigation and test methods are insufficient. Therefore, it was confirmed that the method of field density test is very useful method.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.51-58
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• 2015

PURPOSES : The objective of this study is to compare the densities of asphalt pavements measured both in the field and in the laboratory, and also to evaluate the applicability of field density measuring equipment, such as the pavement quality indicator (PQI), by using statistical analysis. METHODS : For the statistical analysis of the density measured from asphalt pavement, student t-tests and a coefficient of correlation are investigated. In order to compare the measured densities, two test sections are prepared, with a base layer and an intermediate layer constructed. Each test section consists of 9 smaller sections. During construction, the field densities are measured for both layers (base and intermediate) in each section. Core samples are extracted from similar regions in each section, and moved to the laboratory for density measurements. All the measured densities from both the field and laboratory observations are analyzed using the selected statistical analysis methods. RESULTS AND CONCLUSION : Based on an analysis of measured densities, analysis using a correlation coefficient is found to be more accurate than analysis using a student t-test. The correlation coefficient (R) between the field density and the core density is found to be very low with a confidence interval less than 0.5. This may be the result of inappropriate calibration of the measuring equipment. Additionally, the correlation coefficient for the base layer is higher than for the intermediate layer. Finally, we observe that prior to using the density measuring equipment in the field, a calibration process should be performed to ensure the reliability of measured field densities.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.352-359
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• 2005

In this study, seismic refraction survey and MASW at dam crest and down-hole test and cross hole test in the boring holes located in dam crest through the core are performed to fin out dynamic material properties, are needed to evaluate dynamic safety of rockfill dam using dynamic analysis method. From the field test and geophysical exploration, applied such as above, p-wave and s-wave velocity profile of each layer of dam body. Dynamic material properties, such as elastic modulus, shear modulus, poissong's ration, are obtained from p-wave and s-wave velocity profile and density profile from formation density logging test.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.45-58
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• 2015

Even though the plate bearing test (PBT) to evaluate the load baring capacity and the field density test to evaluate the relative density are mainly used for quality control of soil compaction in Korea, use of the dynamic cone penetrometer test (DCPT) and the dynamic plate bearing test (DPBT) considering economic feasibility, rapidity, and suitability for field conditions increase to use for quality control of soil compaction. In this study, bearing capacity and relative density of subgrade with thickness of 20 cm, 30 cm, and 40 cm are estimated using PBT, DCPT, DPBT and field density test in three field compaction tests, and the relationship among various compaction evaluation methods is analyzed and discussed.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.47-52
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• 2009

A sand replacement method is commonly used to determine the density of the compacted soils. The density of the test or compacted soil is computed on the assumption that the calibration container has approximately the same size or volume and allows the sand to deposit approximately in the same way as a test hole in the field. The sand filling process is simulated in the laboratory and its effect on the determination of density is investigated. Artificially-made holes with different heights and bottom shapes are prepared to simulate various shapes of the test hole in the field. Three sands with different gradations are used in the testing to examine how sand grain size influences the determination of density in the field. As the height of a test hole increases, the error between known density and calculated density decreases, regardless of the types of test hole and sand used. The results of this study can be used to reevaluate and revise the test method for soil density by the sand replacement method.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.13-17
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• 2013

Determination of geotechnical characteristics of soil is either to use the field samples to measure the characteristics of soil through laboratory test or measuring the characteristics directly in the field. Field test can be derived similar value by considering characteristics of site and laboratory test can be confirmed the characteristic of soil by testing with field samples. This article describes relative density as the measure of compaction for cohesionless soils and presents several simple and mathematical relationships to help engineers estimate needed parameters for relative density calculations. The main purpose of this research is to investigate possible correlations between coefficient of uniformity, coefficient of curvature, maximum and minimum void ratio, mean grain size. Results show a linear relationship between the minimum and maximum void ratios and a power function relationship between coefficient of uniformity and the limiting void ratios. Void ratio range, which is the difference between the maximum and minimum void ratios, appeared to be log normally distributed but showed no simple mathematical fit to the data. these results were shown to help engineers estimate needed parameters for relative density calculations.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1199-1204
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• 2005

The purpose of field monitoring system in KHC-Test Road located at Joongbu-Inland Highway, is to provide the performance data for traffic and environmental loadings from pavement surface. Among them, water content reflectometers(WCR) are used to measure the volumetric water content of subgrades soils used in test roads. However, most of the WCRs are not well-calibrated based on the field conditions. In this study, the laboratory based test is performed at various density conditions to evaluate the volumetric water content in subgrade Soils with a WCR. Based on the laboratory testings, the effect of density on WCR measurement are well evaluated for predicting the volumeric water content.of subgrades soils in KHC-Test road.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.50.1-50.1
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• 2020

In this topic, I will introduce a recent work on reconstructing the cosmic density field based on the GAN. I will show the performance of the GAN compared to the traditional Unet architecture. I'd also like to discuss a 3-channels-based 2D datasets for the training to recover the 3D density field. Finally, I will present some performance tests based on the test datasets.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.306-313
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• 2005

For seismic response analysis of rockfill dam, dynamic material properties, by field test, are needed. Density and elastic wave profiles have to be known to get an information of the material properties of structure. In this study, various field tests are applied to the example of rockfill dam to get an information of dynamic material properties and seismic safety is evaluated by seismic response analysis with the result of field tests.