• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.5-12
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• 2016

Investigation of in-situ ground in cold region is difficult due to low accessibility and environmental factors. In this study, correlation between dynamic cone resistance and shear strength is suggested to estimate the strength of frozen soils by using instrumented dynamic cone penetrometer. Tests were conducted in freezing chamber after preparing sand-silt mixture with 2.3% water content. Vertical stresses of 5 kPa and 10 kPa were applied during freezing, shearing, and penetration phase to compare the dynamic cone resistance and shear strength. The dynamic cone resistance, additionally, is calculated to minimize the effect of energy loss during hammer impact. Experimental results show that as the shear strength increases, the dynamic cone penetration index (DCPI) decreases nonlinearly, while the dynamic cone resistance increases linearly. This study provides the useful correlation to evaluate strength properties of the frozen soils from the dynamic cone penetration and direct shear tests.

• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.132-148
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• 2019

Recently, safety and environmental concerns have become major social issues. Especially, a special underground-safety law has been made and enacted to prevent ground subsidence around construction sites. For environmental problems, several researches have started or will start on characterization of contaminated sites, in-situ environmental remediation in subsurface, and monitoring of remediation results. As a part of the researches, geophysical surveys, which have been mainly applied to explore mineral resources, geological features or ground, are used to characterize not only contaminated areas but also fluid flow paths in subsurface environments. As a basic study for the application of geophysical surveys to detect contamination in subsurface, this paper analyzes previous researches to understand changes in geophysical properties of contaminated zones by various contaminants such as leachate, heavy metals, and non-adequate phase liquid (NAPL). Furthermore, this paper briefly introduces how geophysical surveys like direct-current electrical resistivity, induced polarization and ground penetration radar surveys can be applied to detect each contamination, before analyzing case studies of the applications in contaminated areas by NAPL, leachate, heavy metal or nitrogen oxides.

• Journal of the Korean Institute of Educational Facilities
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• v.25 no.5
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• pp.3-12
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• 2018

The purpose of this study is to examine the degree of appropriateness of using design quality indicators for the educational building, and complements for design quality indicators. For doing this, each items of the Korean educational building design indicator was validated by teachers, school staff and an education officer. First, School Personnel and Teachers considered indicators for the classroom designed for general subjects as being valid. However, in terms of indicators for the outside space, they thought of them as not being valid. In particular, it seemed that school staff would have a passive attitude toward the open of the school facility for the local society. It is judged that there happens an adverse effect caused by the open of the school facility for the local society in the educational environment of the school. Second, Education Office Supervisors thought that eco-friendly indicators, LED lighting, an outer wall, and widows and doors had a high validity. On the contrary, he viewed the validity of a rainwater retention basin as being low, which was likely because he rarely had expertise on the construction. When it comes to the indicator of technology capability, ultrahigh-speed information network was seen as being valid, and the indicator of economic feasibility had high validity on maintenance and durability. Third, compared to groups of Teachers and School Personnel, the group of education officers presented high validity of indicators. Validity of indicators might be differently showed because different items on indicators were measured. However, it is speculated that Education Office Supervisors mostly acknowledged the validity of indicators. Fourth, a majority of Teachers, School staff, and Education Office Supervisors were favor of the system of the evaluation accreditation for school facilities since it played a guide role in improving the quality of school. In order to settle the system of the evaluation accreditation for school facilities, it is most important that institutions in the local society which are publicly reliable should participate in the phase of designing the system of the evaluation accreditation for school facilities. In sum, overall respondents agreed with the system of the evaluation accreditation for school facilities but were aware that reliable organizations in public would need to take part in planning the system of the evaluation accreditation for school facilities from the beginning.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.605-618
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• 2018

Korea follows the slope design criteria during construction. It was enacted by the Ministry of Land, Transport and Maritime Affairs. There are cases where the Soil-nail is designed as a measure to secure slope stability. The arrangement of the soil-nail may be arranged at equal intervals or may be arranged differently depending on the soil failure model. The optimum design of the countermeasure method is determined by securing stability of the slope through optimization of dimensions and shape. However, when uniform nails are placed at low elevations in slopes, the standard safety factor is exceeded, which may hinder economic design. It is preferable to arrange the reinforcement of the nails over the entire slope. When the horizontal spacing of the nails was topology optimized according to the slope height, it was possible to minimize the amount of reinforcement while satisfying the standard safety factor. Since the active load is reduced in the section where the slope height is lowered, the safety factor after reinforcement may be excessively increased. Therefore, the phase optimization method is proposed as an economical optimal design method using the reinforcing shape density. In addition, a relational expression was designed to optimize the horizontal spacing by slope height.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.5
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• pp.253-264
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• 2019

Storm surges caused by a typhoon occur during the summer season, when the sea-level is higher than the annual average due to steric effect. In this study, we analyzed the sea-level pressure and tidal data collected in 1 h intervals at Incheon, Kunsan, Mokpo, Seogwipo stations on the Yellow Sea coast to analyze the summer season storm surge and wave overtopping. According to our analyses, the summer mean sea-level rise on the west and south coasts is approximately 20 cm and 15 to 20 cm higher than the annual mean sea-level rise. Changes in sea-level rise are closely related to changes in seasonal sea-level pressure, within the range of 1.58 to 1.73 cm/hPa. These correlated mechanisms generates a phase difference of one month or more. The 18.6 year long period tidal constituents indicate that in 2090, the amplitude of the $M_2$ basin peaks on the southwest coast. Therefore, there is a need to analyze the target year for global warming and sea-level rise in 2090. Wave overtopping was simulated considering annual mean sea-level rise, summer sea level rise, the combined effect of nodal factor variation, and 100-year frequency storm surge. As a result, flooding by wave overtopping occurs in the area of Suyong Bay, Busan. In 2090, overtopping discharges are more than doubled than those in Marine City by the recent typhoon Chaba. Adequate coastal design is needed to prepare for flood vulnerability.

• Journal of Conservation Science
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• v.36 no.6
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• pp.494-504
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• 2020

Ten historic sites (denoted as A- J in this study) of a tomb were found during the construction of the east-west expressway in District 2 of Hyangnam, Hwaseong, which is implemented by the Gyeonggi-do headquarters of the Korea Land & Housing Corporation. Thetombswere first detected at siteH, and further investigations revealed various tombs from the Three Kingdoms period; artifacts such as gilt-bronze shoes and caps were excavated from wooden coffins in the tombs. The pottery examined in this study was the only pottery artifact excavated from the site. Its raw clay was soft and loose, reddish brown, and had quartz and feldspar particles of < 1 mm, which appeared to have been added as reinforcing agents. The firing temperature of the pottery was estimated to be under 800-870 ℃ as the mica remains and tridimite, which is the phase transition mineral of quartz, was not produced; a slight endothermic peak was also detected because of the hydration of sericite at 800 ℃. The condition of the artifact was severely weakened because of various factors, such as soil pressure from the stratum formed over the site and repeated freezing and thawing. The artifact could not be collected alone, and thus, surrounding soil that had attached to the artifact was also collected; the artifact was transported to the laboratory and conservation treatment was conducted in a safe and systematic manner.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.3
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• pp.63-82
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• 2022

The purpose of this study is to compare growth condition of landscape woody plants growing on the different ground structures in apartment complex. I chose Manseok Beach Town Complex 2, in Manseok-dong, Seo-gu, Incheon which has both natural and artificial ground as a subject site. Analysis of three phases of soil showed that artificial ground had average liquid phase of 30.89%, artificial ground mounding 33.88% and natural ground 24.40%. It means that artificial ground has higher water content than natural ground despite having same earthiness. It is believed that artificial ground is not as well drained as natural ground even though it is connected to the natural ground and has a deep soil depth because of mounding. Comparative study between woody plants on natural ground and those on artificial ground demonstrated that trees on natural ground grew 40.4% compared to those on artificial ground(0.875mm more) in terms of diameter growth. Average diameter growth of trees on natural ground was 3.040mm against 2.165mm for those on artificial ground. All 19 tree species which were measured for root diameter growth showed similar or higher growth on natural ground than on artificial ground. When it comes to growth of height, arborvitae showed highest growth on natural ground, followed by Thuja occidentalis, Pinus strobus, Magnolia denudata, Diospyros kaki and Aesculus turbinata. I measured branch growth and rate of leaf adherence of Pinus strobus. Average annual rate of branch growth of woody plants on natural ground was twice as high as those on artificial ground. I could conclude that ground structure influences branch growth of Pinus strobus. Statistics analysis of tree damage demonstrated significant result, meaning that there is a difference in the average damage rate depending on structure of ground. In order to validate growth difference by planting ground, I conducted T-Test of growth of diameter, root diameter, branch and height on woody plants growing on natural and artificial ground. As a result, it is believed that there is a difference in the growth of trees depending on the ground structure. Putting all these results together demonstrates that woody plants on natural ground generally grow better than those on artificial ground, which means ground structure does have an influence on the environment of growth of trees.

• Journal of the Korean Geotechnical Society
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• v.25 no.8
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• pp.33-45
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• 2009

The conventional single-core PBDs have been widely used in order to accelerate consolidation settlement of soft grounds. When using the single-core PBD in a thick clay deposit, a delay of consolidation may occur due to high confining pressure in the thick deposit and necking of drains. This study is to compare the performances of soil improvement by the single-core and double-core PBD installed at a site in Busan New Port which exhibits approximately a 40m-thick clay layer. An in-situ test program was performed at the test site where a set of the double-core PBDs and single-core PBDs were installed to compare the efficiency of each drain. In addition, the discharge capacity of each PBD has been measured using the modified Delft Test. A series of laboratory tests for estimating in-situ soil properties have also been performed in order to obtain input parameters for a numerical program ILLICON. The discharge capacity of the double-core PBD is higher than that of the single-core PBD in the modified Delft Test. However it is observed from the comparative in-situ test and numerical analysis that there is no difference in the performance of ground improvement between the two drain systems. This discrepancy comes from the fact that the amount of water released during consolidation in most common field conditions is much smaller than the capacity of even the single core PBD. And thus, considering actual field conditions, it can be concluded that the single-core PBD has enough discharge capacity even in the thick clay deposit such as this test site.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.87-98
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• 2007

A series of dilatometer test, field vane test, and $CK_0U$ triaxial test were performed for clayey soils of Busan new port site to develop the relationships between undrained shear strength and the DMT results. Normalized undrained shear strength is turned out to be $S_{u(CKU)}/{\sigma}'_v=0.30{\sim}0.35\;for\;CK_0U$ triaxial test and ${\mu}S_{u(VST)}/{\sigma}'_v=0.20{\sim}0.22$ for vane shear test. By comparing the undrained shear strength estimated from DMT indices with the results measured by in-situ vane test or $CK_0U$ triaxial test, two methods to predict the undrained shear strength from DMT results are suggested. One is based on the relationship between $S_u/{\sigma}'_v$ and horizontal stress index (KD) while another method comes from $N_c-I_D$ and $N_c-E_D$ correlation. It was observed that the method based on $N_c-I_D\;or\;N_c-E_D$ relation shows slightly better accuracy than the one based on $K_D$ although all of the methods suggested in this study provided comparable values of predicted undrained shear strength. Since the definitions of $I_D\;and\;E_D$ contain $p_1-p_0$, in which soil condition is reflected, it is believed that the prediction method using $N_c$ is capable of taking a material type into consideration.

• Design Convergence Study
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• v.15 no.5
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• pp.71-83
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• 2016

Interior panels are usually used in finishing of interior walls for not only decorative effects but also information transfer. According to designer's design placing interior panels may need repetitive tasks and the emphasis of this paper is to support an automation of these tasks. Considering the utilization characteristics of interior panels, we propose three method to present patterns by using bitmap image pixels and interior panels' shape changes, based on the theoretical consideration. In addition, in order to approve the possibility of the proposed methods, we have implemented the BIM based interior panels auto layout tool which applied one of the three methods to present patterns by using bitmap image pixel values and panel identification attributes. This tool also supports auto generation of quantity and panel arrangement sequence information that will be used in future construction phase. We expect that this approach will also be used in other decorative objects which require repetition of the basic units, such as floor tiles.