• Geomechanics and Engineering
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• v.19 no.4
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• pp.329-342
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• 2019

In this paper, the effect of a group of sand columns in the loose soil bed using triaxial tests was studied. To investigate the effect of geotextile reinforcement type on the bearing capacity of these sand columns, Vertical encased sand columns (VESCs) and horizontally reinforced sand columns (HRSCs) were used. Number of sixteen independent triaxial tests and finite element simulation were performed on specimens with a diameter of 100 mm and a height of 200 mm. Specimens were reinforced by either a single sand column or three sand columns with the same area replacement ratio (16%) to evaluate the Influence of the column arrangement. Effect the number of sand columns, the length of vertical encasement and the number of horizontal reinforcing layers were investigated, in terms of bearing capacity improvement and economy. The results indicated that the ultimate bearing capacity of the samples with three ordinary sand columns (OSCs) is eventually about 11% more than samples with an OSC. Also, comparison of the column reinforcing modes showed that four horizontal layers of geotextile achieved similar performance to a vertical encasement geotextile at the 50% of the column height, from the viewpoint of strength improvement, while from the viewpoint of economy, the geotextile needed for encasing the single column is around 2.5 times of the geotextile required for four layers.

• Journal of the Korean Geosynthetics Society
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• v.11 no.1
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• pp.35-45
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• 2012

Dynamic characteristics of decomposed granite soil mixed with stone sludge and bentonite were investigated to figure out adequate applications of stone sludge, A total of 16 specimens with different stone sludge contents of 0%, 5%, 10%, 15% and bentonite with 0%, 5%, 10%, 15% were prepared. Resonant column tests were carried out on each specimen at different confining pressure. The results showed that the optimum mixing ratio which can satisfy the maximum shear modulus and the minimum damping ratio of the decomposed granite soils ranges from 5% to 10% respectively.

• Korean Journal of Heritage: History & Science
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• v.49 no.4
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• pp.4-21
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• 2016

Until now, most studies regarding stone pagodas of the Honam region have been about stone pagodas with Baekje style because it was the territory of Baekje. However, after reviewing the designated cultural properties, I found that among the 94 stone pagodas in the Honam region there are 15 stone pagodas with Baekje style built in the Goryeo Dynasty and 34 stone pagodas with Silla style. So far, most research efforts have been concentrating on stone pagodas with Baekje style. Through a review of stone pagodas with Silla style, I sought to reveal new aspects of the pagodas in the Honam region. After reviewing the placement of pagodas, I found stone pagodas with Silla style were built mostly in South Jeolla Province during the Unified Silla period. However, in the Goryeo Dynasty stone pagodas with Silla style were erected throughout the Honam region. This shows enhanced Buddhist control over the Honam region than in the previous period. It can be verified especially in Gimje, Jeongeup, Sunchang, Damyang, Yeongam, and Gangjin, where stone pagodas with Baekje style and stone pagodas with Silla style coexist. The types of stone pagodas with Silla style in the Honam region can be divided into two. There are 21 pagodas with two-story foundation, and 12 with single foundation. They seem to have inherited characteristics of the two-story foundation of Silla pagodas. Two pagodas with single foundation were made of a single rock or natural rock for lower foundation. Regarding the body of the pagoda, there are 21 three-story pagodas and 12 five-story pagodas. 25 pagodas have first floors made of a single rock. These are likely to be in the tradition of Silla pagodas. However, the lower part of the roof stones vary as there are three, four, or five-tiered ones. Overall, 12 out of 16 pagodas with middle column in foundation, and 15 out of 21 three-story pagodas are located in South Jeolla Province. This proves that stone pagodas in the South Jeolla Province well maintained the tradition of Silla and became popular.

• Korean Journal of Heritage: History & Science
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• v.42 no.2
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• pp.86-109
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• 2009

Mireuksa Temple was founded during the reign of King Mu of Baekje(AD 600-641). The circumstance of the construction of this temple is documented in "Memorabilia of the Three Kingdoms (Samgukyusa)". The pagoda named stone pagoda at Mireuksaji temple stands outside the main sanctuary of the western area. The south and west sides of the stone pagoda have completely collapsed, leaving only the eastern facade of six of its levels intact. Through the recent discovery of sarira reliquary we can see that the erection of this pagoda was in 639. So owing to accumulation of excavation results about Baekje temple site and vigorous academic exchange, it is possible that architecture of western pagoda at Mireuksaji temple can be understood in connection with the architectural development of wooden pagoda from 6th to early 7th century in East Asia. So this study is on the consideration of building of this pagoda putting first structure of upper part and cross-shaped space in 1st floor. It was considered that the material characteristics as stone could be applied to the temple pagoda architecture of large scale. The results are as follows. First, it had been built in recognition that the outer and inner part of pagoda should be separated. As it is the expression of structural system in temple pagoda architecture of large scale at that time. In pagoda there was a self-erected structure and the members of outer part of it were constructed additionally. Second, in Mireuksaji stone pagoda there is central column with stones. With inner part of pagoda it can be regarded as mixed structural system that constitutes central contral column and inner structural part. And it could be a kind of middle step to more developed structure of whole as wooden pagodas in Japan. Third, as the sarira reliquary was in central column on the first floor, the cross-shaped space could be made. The formation of this space was so on the natural meaning of sarira that the concept as memorial service of graves could be apllied to the pagoda. The style of tomb in Baekje was expressed to the space of 1st floor in pagoda where Sarira had been mstalled. That was not only effective presentation of symbolic space but also easier method in the use of same material.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.93-101
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• 2008

This paper presents the results of numerical investigation on support mechanism of geogrid-encased stone columns for use in soft ground improvement. A number of cases were analyzed using a 3D stress-pore pressure coupled model that can effectively model construction sequence and drainage as well as reinforcing effects of geogrid-encased stone columns. The results indicated that the geogrid encasement provides additional confinement effect that reduces vertical stress in the soft ground, thus resulting in less excess pore water pressures and associated settlement. Also revealed was that such a confinement effect depends on encasement length and stiffness of geogrid. It is also shown that there exist critical encasement length and stiffness of geogrid for a given condition.

• Journal of the Korean GEO-environmental Society
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• v.7 no.1
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• pp.5-18
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• 2006

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete. Finally, a regression formula for calculating settlement reduction coefficients is proposed in this study by using numerical analysis results and applicability of the proposed method is identified by a series of parametric study about settlement reduction coefficients.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.336-342
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• 2005

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1115-1122
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• 2011

Reinforced-Roadbed materials are usually composed of crushed stones. Repeated load application can induce deformation in the reinforced-roadbed layer so that it causes irregularity of track. Thus it is important to develop a prediction model of elastic modulus based on stress-strain relation under repeatitive load in order to investigate behavior of reinforced roadbed. The prediction model of elastic modulus of the material can be obtained from repeated triaxial test. However, a proper size of the sample for the test must be used. In this study, a large repeatitive triaxial test apparatus with the sample size of diameter of 30 cm and height of 60cm was adapted for performing test of the crushed stone reinforced-roadbed considering large particle size to get resilient modulus Mr. The obtained resilient modulus was compared to shear modulus obtained from mid size resonant column test. The sample size effect is somewhat large enough so that it is required to design a scale factor based on similarity law in order to use smaller samples for getting elastic modulus of the crushed stone reinforced-roadbed material. A scale factor could be obtained from this study.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.22-32
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• 2011

The purpose of this study is on the application of the facade design of k-national university in deagu. The subjects of the study examined 75 buildings from the 117 university buildings in main campus. The analysis items is analyzed by several elements; flat and sloping roof, main entrance, design principle, style of architecture, finishing materials, and characteristics of design surveyed by analysis items. The results are as follows: In the 1950s, 2 subjects have shown conflicting characteristics except brick finishing materials. In he 1960s, flat make up 75% of a whole, centrality in main entrances occur, but have an asymmetrical, during this period vertical motif have been underlined by repetition of column, stone has application to main adminstration building. The buildings in the 1970s were so characteristics of modern architecture by painting and flat except main entrance at the center of facade. In the 1980s, position of main entrance have a corner of a wall, finishing materials of a wall were beginning to use stone, glass and metal. The buildings in the 1990s and 2000s are looking a three-dimensional composition by rhythm of superimposition and segmentation and all finishing materials of analysis items are in use.

• Geotechnical Engineering
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• v.8 no.3
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• pp.75-88
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• 1992

In this study the foundation methods which our ancestors, through a historical age as early as three kingdom's period, adopted for their civil structures and buildings have been reviewed by investigating the discovered relics. It is shown that they already, from about 2000 years ago, had applied various foundation techniques considering the structure types and the foundation soil conditions. The ancient foundation methods are categorized as artificially laid alternating soil and boulder layers under heavy structures, compacted soil base under wide loaded area, stone column under pillars of buildings, stacked long stone footing for special buildings such as palace buildings, and piling for bridges, They are analyzed with respect to current foundation techniques.