• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.487-497
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• 2016

If a tunnel is excavated, the released stress is redistributed in the ground around the tunnel face, which lead the stress state of the surrounding ground of the tunnel and the load acting on the tunnel support to change. If the tunnel face deforms, the ground ahead of it is relaxed, and the earth pressure acting on it decreases. And if the displacement increases so much that, the ground ahead of the tunnel face reaches in failure state. At this time, load would be transferred longitudinally in the tunnel, depending on the cover and the face deformations. The longitudinal load transfers in the tunnels induced by the tunnelling has been often studied; however, the relation between the deformation of the tunnel face and the longitudinal load transfer was rarely studied. Therefore in this study assesses the characteristics of the longitudinal load transfer as the face was failed by displacement by conducting a model test in a shallow tunnel. In other words, the longitudinal load transfer of the tunnel with the progress of the face deform was measured by conducting a model test, beginning at the state of earth pressure at rest. As results of this study, most of the longitudinal load transfers occurred drastically at the beginning of the displacement of the tunnel face, and as the displacement of the face approached the ultimate displacement, it converged to the ultimate displacement at a gentler slope. In other words, when the ground ahead of the tunnel face was still in an elastic state, the longitudinally transferred load increased sharply at the beginning stage but it tended to increase gradually if it approached to the ultimate limit. Thus, it was noted that the earth pressure in the face and the longitudinal load transfer of the tunnel had the same decreasing tendency.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1043-1045
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• 1995

The overtone of the ν2 vibrational mode in Cr(CO)6 are observed for the first time in cyclohexane and methanol at both the 266 and 213 nm excitations. The appearance of the overtones due to the displacement of the electronic excited state with respect to the ground state along the ν2 vibrational mode is interpreted in terms of wavepacket concept and molecular orbital (MO) theory. Our Raman results suggest a new interpretation for the excited state potential.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.2
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• pp.1-9
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• 2000

Recently, the number of unsold apartments has been increasing, and apartment furnishing companies have tried a marketing strategy by utilizing the outdoor space for differentiation. There are many differentiation strategies. One of them is to improve the dwellings-on-ground space in apartment complex. Owing to the high density and high-rise of apartment buildings, the dwellings-on-ground apartment complex have been recognized as not good housing by residents in korea. The precedent study on the responses from residents showed the negative effects mainly due to sunlight, daylight, view and privacy and the positive effects from good accessibility and good environment for children and elderly people. The purpose of this study was to improve the dwellings-on-ground space and to suggest the most appropriate type of the dwellings-on-ground space through the residents' desires and preferences. In this point of view, this study shows three results for the design improvement: 1) Providing private gardens and individual accesses to the dwellings-on-ground. 2) Providing private garden with flower bed to intensify the visual aspect. 3) Furnishing variable transformation of unit plan in dwellings-on-ground, for example, maisonette, etc.

• Computers and Concrete
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• v.11 no.1
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• pp.39-49
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• 2013

The use of ground fly ash in concrete can increase the risk of slump loss due to the drastic surface change of the particles after the grinding treatment and the accelerated reaction compared to the untreated ash. This study is aimed at the early age hydration and time-dependent rheology changes of cement paste containing ground fly ash. An original fly ash is ground into different fineness and the hydration of cement paste containing the ground fly ash is monitored with the ultrasound propagation method. The zeta potentials of the solid particles are measured and the changes of rheological parameters of the cement pastes with time are analyzed with a rheometer. A particle packing model is used to probe packing of the solid particles. The results show that the early age hydration of the paste is strongly promoted by replacing Portland cement with fly ash up to 30 percent (by mass), causing increase of the yield stress of the paste. The viscosity of a paste containing ground fly ash is lower than that containing the untreated ash, which is explained by the denser packing of the solid particles.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.131-137
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• 2003

This thesis is results of centrifuge model experiments to investigate the behavior of replacement method in dredged and reclaimed ground. For experimental works, centrifuge model tests were carried out to investigate the behavior of replacement method in soft clay ground. Basic soil property tests were performed to find mechanical properties of clay soil sampled from the southern coast of Korea which was used for ground material in the centrifuge model tests. Reconstituted clay ground of model was prepared by applying preconsolidation pressure in 1g condition with specially built model container. Centrifuge model tests were carried out under the artificially accelerated gravitational level of 50g. Replacing material of leads having a certain degree of angularity was used and placed until the settlement of embankment of replacing material was reached to the equilibrium state. Vertical displacement of replacing material was monitored during tests. Depth and shape of replacement, especially the slope of penetrated replacing material and water contents of clay ground were measured after finishing tests. Model tests of investigating the stability of embankment after backfilling were also performed to simulate the behavior of the dike treated with replacement and backfilled with sandy material. As a result of centrifuge model test, the behavior of replacement, the mechanism of the replacing material being penetrated into clay ground and depth of replacement were evaluated.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.4
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• pp.43-52
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• 2018

This paper presents the cooling performance analysis results of a ground-source heat pump (GSHP) system using hybrid ground heat exchanger (HGHE). In this paper, the HGHE refers to the ground heat exchanger (GHE) using both a vertical GHE and a surface water heat exchanger (SWHE). In order to evaluate the system performance, we installed monitoring sensors for measuring temperatures and power consumption, and then measured operation data with 4 different load burdened ratios of the hybrid GHE, Mode 1~Mode 4. The measurement results show that the system with HGHE mainly operates in Mode 1 and Mode 2 over the entire measurement period. The average cooling coefficient of performance (COP) for heat pump unit was 5.18, while the system was 2.79. In steady state, the heat pump COP was slightly decreased with an increase of entering source temperature. In addition, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further research are needed to optimize the design data for various load ratios of the HGHE.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.41-48
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• 2009

A flexible pipe was buried 10cm below the ground formed with standard sand to observe changes in the shape of the pipe according to the behavior of ground at each relative density. Changes in the shape of the pipe in each ground were observed to examine the behavior of the pipe under the state of reinforced ground after installing geogrid under the pipe. Ground reinforced using geogrid formed tensile force on the reinforcement material with increase in the vertical load and showed reduction in settlement under identical vertical load with existence of reinforcement. Distributions of ground deformation of 100% relative density and 70% relative density had clear difference. Reinforced ground with 70% density converged to the ground reaction of final settlement of non-reinforced ground with 100% density at final settlement of 100 mm. Because the shape of lower part strain of the buried pipe is similar to that of un-reinforced ground with relative density of 100%, reinforcement effect by geogrid in soft ground can be anticipated.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.7-16
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• 1991

This research investigated soil, plants, insects and birds in the Mongchon Earth Fort, establishing the 11 plots, according to planting treatment, in order to present management method for ecological stability of species in the ground covering plots. The results of analysizing the investigated data summarize as follows. 1. In the ground covering plots without upper layer, the density and coverage of middle and low layer in the natural plots were higher than those in the artificial plots. 2. In the ground covering plots without upper layer, the density and coverage of low layer were higher than those in the artificial, while the density and coverage of herb layer in the natural plots were lower. 3. Whether there was upper layer or not, the total species diversity and enenness of the ground covering community in the natural plot without artificial treatment and natural treatment plot were higher than those ground covering. 4. In the ground covering plots with upper layer, the species diversity of ground covering in the plots without artificial treatment is high, while the species diversity in the plots with natural treatment caused the secondary succession is higher than that of the natural plot. 5. In the ground covering plots without upper layer, the species diversity in the plots with artificial management was higher than that of natural plots, while the evenness in the plots with artificial management was lower. 6. In the ground covering plots with upper layer the species diversity of insect in the plot of natural state was higher than that of insect in the plots with artifical treatment. 7. Synthetically, in the area with upper layer the species diversity of the ground covering community in the natural plot was high, while in the area without upper layer, the species diversity of it in the plots with artificial treatment was high. The insect turned up frequently in the plots of high species diversity of the ground covering, so the bird did in the plots of high species diversity of the ground covering and insects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.347-352
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• 2007

Recently, automated construction machines have been developed for technically solving construction industry problems such as labor, productivity, quality and the profit decrease. In domestic construction industry, a research for developing an intelligent excavation robot has been performed. The primary objective of this research is to analysis state-of-the art technologies in order to recognize local ground shape in real-time and compute soil volume of earth moving. This research analyzed five elemental technologies for 3D modeling of local ground shape and selected an optimal technology among the five technologies through using AHP method. It is anticipated that the optimal technology selected for 3D modeling of local ground shape can be effectively used to develop the intelligent excavation robot.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.680-684
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• 2009

The effects of garlic and onion on the microbiological and physicochemical properties of irradiated ground beef patties were evaluated. Ground beef was mixed with 0.5%(w/w) minced garlic or 2.5%(w/w) minced onion, vacuum-packed in oxygen-impermeable nylon/PE bags and then electron beam-irradiated at 2.5 kGy. All samples were kept at $4^{\circ}C$ for 8 d. Irradiation resulted in a 2-log CFU/g reduction in both aerobic and coliform bacteria. The microbial counts gradually increased during storage, but those in beef that contained garlic or onion were 1-log CFU/g lower than those of the control samples after 8 d of storage. The pH value decreased during storage in all meat samples, but this decrease was greater in non-irradiated beef than in irradiated beef. The lipid oxidation, volatile basic nitrogen content and Hunter color values of raw patties were generally not affected by irradiation or the addition of garlic and onion. Sensory evaluation of cooked patties showed that the off-odor was less pronounced in samples that contained added garlic or onion than in control samples, and that the overall acceptability of beef formulated with garlic was the highest. Overall, the results of this study indicate that the addition of garlic or onion in combination with irradiation treatment enhanced the microbial quality and improved the sensory quality of irradiated ground beef.