• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.129-144
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• 2010

The earth pressure acting on the vertical shaft is less than that acting on the retaining wall due to three dimensional arching effect. Thus, it might be essential to estimate the earth pressure actually acting on the shaft when designing the vertical shaft. In this paper, large-sized model tests were conducted as Part II of companion papers to verify the newly suggested earth pressure equation proposed by Kim et al. (2009: Part I of companion papers) that can be used when designing the vertical shaft in cohesionless soils as well as in c-$\phi$ soils and multi-layered soils. The newly developed model test apparatus was designed to be able to simulate staged shaft excavation. Model tests were performed by varying the radius of vertical shaft in dry soil. Moreover, tests on c-$\phi$ soils and on multi-layered soils were also performed; in order to induce apparent cohesion to the cohesionless soil, we add some water to the dry soil to make the soil partially-saturated before depositing by raining method. Experimental results showed a load transfer from excavated ground to non-excavated zone below dredging level due to arching effect when simulating staged excavation. It was also found that measured earth pressure was far smaller than estimated if excavation is done at once; the final earth pressure measured after performing staged excavation was larger and matched with that estimated from the newly proposed equation. Measured results in c-$\phi$ soils and in multi-layered soils showed reduction in earth pressures due to apparent cohesion effect and showed good matches with analytical results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.385-393
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• 2006

Soil nailing is a reinforcement method used for stabilizing excavated walls or slopes. Due to its much advantages such as ease of construction and economical efficiency, use of soil nailing is increased. However, the soil nail has much disadvantages for use in urban area. The soil nail needs to be installed inevitably beyond private land boundary, which causes rent for use. For this reason, removable soil nailing system was developed. However, the removal rate of this system is just about 50￠¦70%. To resolve this problem, the Fiber Reinforced Plastic (FRP) soil nailing system which does not need to be removed and allows for the installation beyond private land, is developed. In this paper, through theoretical and experimental studies in laboratory and field such as prototype tests, pullout tests, we evaluate the stability and behavior characteristics of the FRP soil nailing system. And, numerical analyses using FLAC2D were performed with respect to various soil conditions, where prototype test for excavation wall and pullout tests were carried out. As a result of this study, the FRP soil nailing systems show similar behavior characteristics with those of removable soil nailing system. Finally, considering the serviceability and mechanical stability of FRP soil nailing systems, it is enough to be used as a good alternative of general soil nailing system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5B
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• pp.473-482
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• 2009

This study numerically discusses wave forces acting on a vertical wall such as breakwaters or revetments, subjected to incident undular or turbulent bores. Due to the complex hydrodynamics of bore, its wave forces have been predicted, mainly through laboratory experiments. Numerical simulations in this paper were carried out by CADMAS-SURF(CDIT, 2001), which is based on Navier-Stokes momentum equations and VOF method (Hirt and Nichols, 1981) for tracking free water surface. Its original source code was also partly revised to generate bore in the numerical water channel. Numerical raw data computed by CADMAS-SURF included great strong spike phenomena that show the abrupt jumps of wave loads. To resolve this undesired noise of raw data, the band-pass filter with the frequency of 5Hz was utilized. The filtered results showed reasonable agreements with the experimental results performed by Matsutomi (1991) and Ramsden (1996). It was confirmed that CADMASSURF can be applied to the design of coastal structures against tsunami bores. In addition, the transformation process and propagation speed of bores in the same 2-d water channel were discussed by the variations of water level for time and space. The numerical results indicated that the propagation speed of bore was changed due to the nonlinear interactions between negative and reflected waves.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.179-189
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• 2010

This paper presents a numerical investigation of vorticity generation in fully vegetated open-channel flows. The Reynolds stress model is used for the turbulence closure. Open-channel flows with rough bed-smooth sidewalls and smooth bed-rough sidewalls are simulated. The computed vectors show that in channel flows with rough bed and rough sidewalls, the free-surface secondary currents become relatively smaller and larger, respectively, compared with that of plain channel flows. Also, open-channel flows over vegetation are simulated. The computed bottom vortex occupies the entire water depth, while the free-surface vortex is reduced. The contours of turbulent anisotropy and Reynolds stress are presented with different density of vegetation. The budget analysis of vorticity equation is carried out to investigate the generation mechanism of secondary currents. The results of the budget analysis show that in plain open-channel flow, the production by anisotropy is important in the vicinity of the wall and free-surface boundaries, and the production by Reynolds stress is important in the region away from the boundaries. However, this rule is not effective in vegetated channel flows. Also, in plain channel flows, the vorticity is generated mainly in the vicinity of the free-surface and the bottom, while in vegetated channel flows, the regions of the bottom and vegetation height are important to generate the vorticity.

• Journal of Korean Living Environment System
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• v.24 no.5
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• pp.654-664
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• 2017

The use of environmentally friendly finishing materials allows us to create a space where we can feel nature and to have stability and peace in the city center. In this paper, we examined the sensitivity of people to the three café spaces where wooden finishing materials are used in the space elements that change according to people's demands for environmentally friendly space due to pollution of living environment. First, we examined the wood and finishing materials and emotional vocabulary through literature review and previous research. Second, the values of L ^*, a ^*, b^* and sR, sG and sB values were extracted by using a line spectrophotometer (Ci6X). Third, we conducted a 7 - point scale questionnaire based on the extracted 13 pairs of emotional vocabulary. Using SPSS 21, frequency analysis by descriptive statistics, crossover analysis by visiting purpose and intention, and emotional lexical factor analysis were performed. Through the study, the following points were found. First, CB (The Coffee Bean), SB (Starbucks) and HS (Hollys Coffee) showed differences in CB (65%), SB (40%) and HS (37%) in the spatial analysis. Second, CB gave color similar to the color of wall and furniture wood, but HS changed the color or brightness of wood finishing color of furniture. HS or SB showed favorable use of wood color scheme. Third, SB (26.3%) and HS (19.7%) were selected by taste. Fourth, there were differences in the items of CB, 'local-exotic' and SB 'dark-bright' in the factor value. The use of wood finishing materials differed in the atmosphere evaluation depending on the spatial factors and the color of the furniture. However, in this study, there are many factors that are insufficient in the accuracy of the ratio of the applied wood finishing material to the space element and the amount of the survey. If we further study the evaluation of emotional image according to the ratio of wood finishing materials, we think that it is necessary to study now that interest in environmentally friendly is increasing.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4274-4281
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• 2023

Blanket is of vital importance for engineering application of the fusion reactor. Nuclear heat deposition in materials is the main heat source in blanket structure. In this paper, the three-dimensional method for thermal-hydraulics/neutronics coupling analysis is developed and applied for the full-scale module of the helium-cooled ceramic breeder tritium breeding blanket (HCCB TBB) designed for China Fusion Engineering Test Reactor (CFETR). The explicit coupling scheme is used to support data transfer for coupling analysis based on cell-to-cell mapping method. The coupling algorithm is realized by the user-defined function compiled in Fluent. The three-dimensional model is established, and then the coupling analysis is performed using the paralleled Coupling Analysis of Thermal-hydraulics and Neutronics Interface Code (CATNIC). The results reveal the relatively small influence of the coupling analysis compared to the traditional method using the radial fitting function of internal heat source. However, the coupling analysis method is quite important considering the nonuniform distribution of the neutron wall loading (NWL) along the poloidal direction. Finally, the structure optimization of the blanket is carried out using the coupling method to satisfy the thermal requirement of all materials. The nonlinear effect between thermal-hydraulics and neutronics is found during the blanket structure optimization, and the tritium production performance is slightly reduced after optimization. Such an adverse effect should be thoroughly evaluated in the future work.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.194-201
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• 1995

In order to make clear the resistance of bag nets, the resistance R of bag nets with wall area S designed in pyramid shape was measured in a circulating water tank with control of flow velocity v and the coefficient k in $R=kSv^2$ was investigated. The coefficient k showed no change In the nets designed in regular pyramid shape when their mouths were attached alternately to the circular and square frames, because their shape in water became a circular cone in the circular frame and equal to the cone with the exception of the vicinity of frame in the square one. On the other hand, a net designed in right pyramid shape and then attached to a rectangular frame showed an elliptic cone with the exception of the vicinity of frame in water, but produced no significant difference in value of k in comparison with that making a circular cone in water. In the nets making a circular cone in water, k was higher in nets with larger d/l, ratio of diameter d to length I of bars, and decreased as the ratio S/S_m$ of S to the area $S_m$ of net mouth was increased or as the attack angle 9 of net to the water flow was decreased. But the value of ks15m was almost constant in the region of S/S_m=1-4$ or $\theta=15-90^{\circ}$ and in creased linearly in S/S_m>4 or in $\theta<15^{\circ}$ However, these variation of k could be summarized by the equation obtained in the previous paper. That is, the coefficient $k(kg\;\cdot\;sec^2/m^4)$ of bag nets was expressed as $$k=160R_e\;^{-01}(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for the condition of $R_e<100$ and $$k=100(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for $R_e\geq100$, where $S_n$ is their total area projected to the plane perpendicular to the water flow and $R_e$ the Reynolds' number on which the representative size was taken by the value of $\lambda$ defined as $$\lambda={\frac{\pi d^2}{21\;sin\;2\varphi}$$ where If is the angle between two adjacent bars, d the diameter of bars, and 21 the mesh size. Conclusively, it is clarified that the coefficient k obtained in the previous paper agrees with the experimental results for bag nets.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.5
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• pp.60-70
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• 2017

This study traces the development of physic gardens in Korea and explores their significance in the history of landscape architecture. For this purpose, records related to physic gardens from medical sources from the period of the Three States to the Joseon dynasty, when herbal medicine was systematized as a field, were searched. Physic gardens had been developed by the time of the late Goryeo and early Joseon dynasties, in the 13th and the 15th centuries. Yakpo(kitchen gardens for medicinal herbs) were cultivated by a group of new high-level officials in the late Goryeo dynasty, when an increasing interest in hyangyak(native herbs) emerged under the influence of the Neo-Confucian perspective on nature, which emphasized locality. The sources analyzed in this study confirm that physic gardens called jong-yakjeon(royal medicinal herb gardens) were in operation in the early Joseon dynasty when policies to investigate, discover, cultivate, and research native herbs were put into place. It is likely that the jong-yakjeon were established at the beginning of the Joseon dynasty as subsidiary facilities under its central medical institutions, the Naeuiwon and Hyeminseo, and then declined in the late Joseon dynasty. Jong-yakjeon can be confirmed to have existed in the mid-15th century. Physic gardens were located in several places outside the Fortress Wall of Hanyang, such as Yakhyeon, Yuldo, Yeoudo, and Saari. The total area encompassed by physic gardens was about 160,000 square meters in the early 18th century. In jong-yakjeon, dozens of medicinal herbs were cultivated, including Schizonepeta tenuifolia var. japonica, Rehmannia glutinosa, and Glycyrrhiza uralensis Fischer, and these gardens were operated by physicians dispatched from the Naeuiwon and dozens of provincial slaves. In conclusion, the jong-yakjeon were similar to the physic gardens of Renaissance medical universities in that they reflected the interest in and development of theories about new herbs, and were similar to the physic gardens of medieval castles and monasteries in terms of species types, location, and function. This paper has limitations in that it does not present the specific spatial forms of the yakpo or the jong-yakjeon. Nevertheless, this paper is significant for the field of garden history because it shows that physic gardens in Korea appeared in the late Goryeo and early Joseon dynasties concomitantly with the development of medicine towards native herbs and functioned as utilitarian gardens to cultivate community remedies.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.1
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• pp.105-116
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• 2017

Murals in villages revitalize communities and spaces, and are economically efficient. Central and local governments are therefore actively undertaking Mural Village Projects but there are some issues and concerns about the projects for the provision of uniformed landscapes for the regions that are the result of a short-term completion of projects, and instead of cohesion, cause destruction of place identities. In addition, the problem of sustainable landscape management that is the result of low community involvement can be pointed out because the murals are products of government-led projects. The study covered the context of landscape and space change processes from a critical perspective, and focused on Ihwa-dong Mural Village, which is considered the first mural village in Korea and has begun to undergo drastic changes due to attention received from media. The purposes of this study are as follows. First, the study provides data about difference of place identity perception and landscape preference between residents and tourists in Ihwa-dong Mural Village. Second, this paper evaluates the current Mural Village Projects and finds alternative directions to improve the projects by using these data. This paper analyzed tourist hot spots in Ihwa-dong Mural Village by using SNS analysis, a field study and focus group interviews. The difference of place identity perception and landscape preference was examined among three groups: residents, new residents who are invited by Mural Village Projects, and tourists. This study showed that many tourists are focused on landscape areas that were not intentionally constructed projects. In addition, the locations of preferred landscapes and stores overlapped. Meanwhile, using qualitative data analysis, it was found that residents perceived the area as being an under-privileged location, while the murals, a non-daily landscape, largely affected place identity perception of new residents and tourists. For landscape preference, tourists preferred outdoor rest areas, while new residents and residents preferred less. Additionally, new residents and tourists preferred an area's night view while residents made no mention of this. Related to the direction of the projects, three groups showed their dependence on the government. This empirical study is significant from a participatory design perspective and in analyzing the issues for mural villages' landscapes, which are spreading across the nation and proceeding without criticism in urban regeneration. Implications for urban planners and suggestions for the future projects are given.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.16-33
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• 2012

Maehwa blossom(梅花) has been favoured in literary and artistic works in the East Asia as one of representing symbols of virtuous men's character. Maehwaseookdo(梅花書屋圖) is one of major forms of painting. This paper starts from the birth of Maehwaseookdo since it aims to examine the following points: its structural origin of the Gurimaehwachonsado(九里梅花村舍圖) style; how this style was distributed in Korea; process and features of Maegamdo(梅龕圖). The current academic world admits Maehwaseookdo is originated from an ancient story of Lim Po(林逋). Even though Maehwaseookdo and Lim Po story can be linked to a meaning of schoarly hermitage, ways to structure works are hard to compare paintings based on Lim Po story. While paintings related to Limpo story such as Banghakdo(放鶴圖) and Gwanmaedo(觀梅圖) depict a scholar(s) and a few Maehwa trees with cranes, Maehwaseookdo presents scholarly hermitage with a lot of Maehwa trees which encircle a house building. As other paintings related to Maehwa blossom were widely painted since the nationwide popularity of the theme of Maehwa, Maehwaseookdo was not drown throughout the whole period of time. Since Goryeo, Maehwa paintings including Sehansamu(歲寒三友), ordinary Maehwado as one of the Four Gentlemen's plants, and Tammaedo(探梅圖) which was based on ancient anecdote of Maeng Hoyeon. Maehwaseookdo, however, was created exclusively in the 19th century. In China a similar feature took place much earlier period which was in the 17th century. Accordingly we can assume that these patterns which paintings in particular styles were generated by particular cultural phenomena. The reason why Joseon's Maehwaseookdo works were painted exclusively in the 19th century was that Kim Jeonghee's party and Sin wi had acquaintanceship with Jang Sim(張深) who got work orders for Oh Sungyang(吳嵩梁). In these corresponding activities, two types of Maehwa paintings were exchanged. In China, scholars usually drew paintings in the type of Gurimaehwachonsado(九里梅花村舍圖) depicting scenic views of Guriju(九里洲) which was riverside area under the Mt. Buchun(富春山). This place surrounded by thousands and hundreds of Maehwa trees was where Oh Sungyang(吳嵩梁) was about to retire to hermitage in. In this repect, Joseon scholars painted Maegamdo(梅龕圖) depicting a scene of a shrine with Oh Sungyang(吳嵩梁)'s poetry books surrounded by Maehwa trees for paying tribute to the wall of Maehwa trees(Maebyeok(梅癖)). This seems to adapt the format of 'Manmae(萬梅)' which appeared in the type of Gurimaehwachonsado. One of the representing works of this, is painted or supervised by Sinwi. Paintings in two types with respective meanings were combined by which was estimated to be painted by Sin Wi, then it became a structural base of by Jang Sim(張深) This type of Maegamdo brought the popularity of Maewhoseookdo which once had another name of 'Manmaeseookdo(萬梅書屋圖)' by a group of scholars such as Jo Heeyong, in the 19th century. All things considered, this paper can be a sort of precedent phrase to find out the birth of Manmaeseookdo which was very popular in the late 19th century.