• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.403-415
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• 2014

Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.201-220
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• 2023

Power cable tunnels is one of the underground structures meant for electricity transmission and are constructed using shield TBM method when transitting across urban and subsea regions. With the increasing shaft depth for tunnels excavation when the shield TBM excavated the rock mass, the review of selecting closed-type shield TBM in rocks becomes necessary. A simplified shield TBM design method is also necessary based on conventional geotechnical survey results. In this respect, design method and related design program are developed based on combined results of full-scale tests, considerable amount of accumulated TBM data, and numerical simulation results. In order to validate the program results, excavation data of a completed power cable tunnel project are utilized. Thrust force, torque, and power of shield TBM specification are validated using Kernel density concept which estimates the population data. The robustness of design expertise is established through this research which will help in stable provision of electricity supply.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.1
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• pp.1-17
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• 2024

Analyzing the tunnel excavation behavior and its effect on the surrounding ground involves large deformation behavior. Therefore, in order to properly simulate the tunnel excavation process and rigorously investigate the actual effect of excavation on surrounding ground and tunnel structure large deformation analysis method is required. In this study, two major numerical approaches capable of considering large deformations behavior were applied to investigate the effect of tunnel boring machine excavation on the surrounding ground: coupled Eulerian-Lagrangian (CEL) and the automatic remeshing (AR) method. Relative performance of both approaches was evaluated through the ground response due to TBM excavation. The ground response will be quantified by estimating the range of the excavation damaged zone (EDZ). By comparing the results, the range of the EDZ will be suggested on the vertical and horizontal direction along the TBM excavation surface. Based on the computed results, it was found that the size of EDZ around the excavation surface and the tendencies was in good agreement among the two approaches. Numerical results clearly show that the size of the EDZ around the tunnel tends to be larger for rock with higher RMR rating. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional due to higher confinement stress around the excavation surface.

• Archives of design research
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• v.19 no.4 s.66
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• pp.61-70
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• 2006

The functions and roles in the various fields of modern society are changing into the unified and multiplex structure, which is simultaneous and virtual communication environments beyond physical space and time, by the digital IT technology. The urban traffic system is also being intellectualized in order to solve urban traffic problems and convenient services by using digital IT technology. The bus, which is the one of the most common public transportation, are suffering in the decrease of bus service quality and the bus passengers rate because of the development of other public transportation systems such as the subway and electric railway and by rapidly increasing private cars. By recognizing these problems, many domestic and overseas cities are promoting to introduce the Bus Information System (BIS) to improve service quality of buses through the intelligent traffic system. According to the construction of this new information system called the Bus Information System (BIS), the new bus stop configuration system and design plans are being required to solve the existing bus stop information system. Therefore, this research was conducted to suggest an effective BIS configuration system plan and synthetic design goals based on the investigation the problems of the information system and the BIS configuration system for Busan city. Also, this research are conducted the below actions as follows: First, the literature survey was conducted, such as theoretical documents on the bus stop and the Bus Information System(BIS), Also, the design trend of the BIS was examined through domestic and overseas BIS cases studies. Scondly, the problems related to the information system in Busan city bus stops were investigated to investigate the present state and problems of the Bus Information System (BIS). Finally, as a result of this research, the effective BIS configuration system plan and design approach methods of bus stops were proposed for by Busan city based on the above investigation results.

• Fire Science and Engineering
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• v.29 no.5
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• pp.42-50
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• 2015

Three simulation approaches for turbulence were applied for the computation of propane dispersion in a simplified real-scale urban area with one building:, Large Eddy Simulation (LES), Detached Eddy Simulation (DES), and Unsteady Reynolds Averaged Navier-Stokes (RANS). The computations were performed using FLUENT 14, and the grid system was made with ICEM-CFD. The propane distribution depended on the prediction performance of the three simulation approaches for the eddy structure around the building. LES and DES showed relatively similar results for the eddy structure and propane distribution, while the RANS prediction of the propane distribution was unrealistic. RANS was found to be inappropriate for computation of the gas dispersion process due to poor prediction performance for the unsteady turbulence. Considering the computational results and cost, DES is believed to be the optimal choice for computation of the gas dispersion in a real-scale space.

• Journal of the Korea Institute of Building Construction
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• v.4 no.3
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• pp.109-116
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• 2004

Normally easy task of plat in urban architecture is that using underground full of activities for increase building site efficiency. Especially for using underground space for the parking lot. Also utilize underground is more increase for fulfill requirement in modern society considered with environmental friendly architecture. The primary objective of this study is to apply analyzed formal foundation type for selecting the optimum type of parking lots considered with structural stability, economical efficiency, construction efficiency, construction duration. This study aim to on criteria decided through the questionaries for the selection considered with in the scale of second stories parking lots underground, parking volume is 80 and reinforced concrete structure. The bearing capacity is 6～8m and downward from surface, healthy ground bearing capacity is 40 t/m2. This study comparative analysis and discuss economical efficiency, construction efficiency, construction duration based constructivist stability which applied Single foundation, Mat foundation, Drop Mat foundation. The result of this study is as follows: First, the result of economical efficiency is that on the basis of single foundation, Drop Mat foundation is 1.88, Mat foundation 2.04 as a comparative analysis on the basis of total construction cost included material cost, labor coast and machinery cost. Second, the result of construction efficiency order is single foundation, Drop Mat foundation, Mat foundation as a comparative analysis on the based connected characteristics. Third, the result of construction duration is that on the basis of Mat Foundation, Drop Mat foundation is 1.33, single foundation is 1.87 as a comparative analysis Critical Path. Forth, Each foundational type characteristics order through the matrix method is that overall each formal type of foundation contraries at economical efficiency and construction efficiency, construction duration. Also expect contradiction between engineers and owners due to engineer pursuit construction duration and ewer to begin with economical efficiency. Fifth, The selection of suitable foundation formal type needs that based consider project characteristic and field condition as according to above result of a comparative analysis. As a result, a comparative analysis economical efficiency, construction efficiency, construction duration of Mat foundation, Drop Mat foundation, single foundation with 3Bay reinforced structure underground parking lots on the healthy ground.

• The Journal of the Acoustical Society of Korea
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• v.24 no.8
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• pp.481-491
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• 2005

The purpose of this study is to interpret the evaluation structure of auditory images about streetscapes in urban area on the basis of the semantic view of soundscapes. Using the caption evaluation method. which is a new method, from 2001 to 2005, a total of 45 college students participated in a fieldwork to find out the images of sounds while walking on the main streets of Namwon city. It was able get various data which include elements, features, impressions, and preferences about auditory scene. In Namwon city, the elements of the formation of auditory images are classified into natural sound and artificial sound which include machinery sounds, community sounds. and signal sounds. Also, the features of the auditory scene are classified by kind of sound, behavior, condition, character, relationship of circumference and image. Finally, the impression of auditory scene is classified into three categories, which are the emotions of humans, atmosphere of the streets, and the characteristics of the sound itself. From the relationship between auditory scene and estimation, the elements, features and impressions of auditory scene consist of the items which are positive, neutral, and negative images. Also, it was able to grasp the characteristics of auditory image of place or space through the evaluation model of streetscapes in Namwon city.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.45-56
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• 2021

As the utilization of the underground space is activated, deep excavation of ground has been conducted for the installation of underground structures, the earth retaining wall has widely used to minimize deformation of the excavated ground. In particular, as deep excavation is actively progressing in an urban area where structures are concentrated, methods to minimize the deformation of wall have been devised to prevent damage to the structure adjacent to the wall, and one of these methods is the pre-loading method. This method is a method of suppressing the deformation of wall by actively applying a load on the strut to be installed in wall, and research on this method has been conducted recently. However, although related studies have been actively conducted, the management standard for the pre-loading of bracing has not been clearly presented until now. In addition, since the working force in the strut may increase depending on the depth of excavation or the soil condition of the backfill, the magnitude of the pre-loading that can be applied to the brace may decrease. Nevertheless, the magnitude of the pre-loading (more than 50% of the working load) proposed by the previous research results has been uniformly applied to the strut. In this study, 3D finite element analysis was performed to evaluate the application range of the pre-loading of H-beam strut according to the soil conditions of backfill. As a result of the analysis, it was found that there is a very high possibility that a problem may occur in the stability of the structure of strut due to the earth pressure and the pre-loading when the soil condition is weak and deep excavation proceeds. And it was found that the application range of the pre-loading was 5%~70% of the working load in strut.

• Journal of the Korean Geosynthetics Society
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• v.20 no.1
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• pp.1-8
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• 2021

In urban areas, structures are installed deep underground in the lower part of the structure to utilize space. Therefore, a retaining wall is used to prevent earth pressure from the ground when constructing a structure. Due to the development of construction technology, retaining wall applied to excavation work are used to prevent danger such as falling rocks and landslides in temporary facilities when construction or retaining walls are installed. In general, the application of a retaining wall to a temporary facility during the embankment construction is the case of expanding an existing roads or railways. Therefore, it is necessary to study the retaining wall applied to the embankment construction such as the double-track site of the high-speed railway. In this study, two types of common one row H-pile retaining wall and two types of IER retaining wall were analyzed, and the stability of the retaining wall applied to the construction of double-track of the high-speed railway was analyzed. The earth retaining wall is a construction method that combines forced pile applied to the stabilization of the slope with the wall of the earth retaining wall. As a result of the analysis, the IER retaining wall had maximum lateral displacement of 19.0% compared to the type with H-plie installed only in the front while dynamic load was applied. In addition, the slower the speed of high-speed railway, the more displacement occurred, and the results show that more caution is needed when designing the ground in low-speed sections.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.3
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• pp.97-110
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• 2012

This study aimed at considering the original shape of Iljiam Tea Garden at Mt. Daedun. In order to accomplish our goal, we tried to strengthen the authenticity of construction of Iljiam by comparing its space structure depicted in the poetry of Choeui(艸衣) the monk with its current restored state. According to the clues and situation in the poetry along with symbolic words like 'Choeui' and 'Ilji(一枝)', Iljiam seemed to be a tea garden with elegant and celestial beauties, and with a nice view where Choeui the famous monk searched for the highest state of enlightenment by enjoying and living in nature. When we compared the plural aspects of Iljiam like Dacheon(茶泉), Dajo, Mulhwak, Darim(茶林), Chaewon(菜園), and Yeonji(蓮池) with those of Dasan Tea Garden[茶山草堂], we could see that the basic components of tea-culture space of both gardens are the same, showing the organizational principle of the top and bottom area to stress reading and studying. When it is restored, the authenticity of Iljiam should be pursued by linking spatial, historical, and landscaping characteristics as the space of which Choeui the monk carried out Zen meditation and mastered tea. However, the recent grand scale Buddhist business like the expansion of access road and construction of Buddhist sanctuary and Seolimdang became the biggest threat to the authenticity. Especially, it was emphasized many times in various poetry that the view from Iljiam and its surroundings is extraordinary, so it is critical to get rid of obstacles to the view from Iljiam and its surroundings in order to restore Iljiam as its genuine form. The current Iljiam should be re-made because it is like a leaf-roofed garden, not like a hermitage. However, the opinion that Jawoohongryeon-sa(紫芋紅蓮社) is somewhat a Taoistic and Taoist hermit space with a special shape adopted the pattern of building of the Joseon period rather than a Buddhist building can be accepted as long as other convincing historical evidences are found out, considering the ideology of uniting Confucianism and Buddhism and the spirit of Taoist hermit found out from poetry of Choeui and his friends. In conclusion, the restoration of Iljiam in 1979 was carried out to restore the place of Iljiam rather than to restore the originality of Iljiam by combining and referring domestic cases of tea gardens. However, there is not much material for restoration even though the main frame of Iljiam was distorted. Nevertheless, the top and bottom ponds should be constructed as a rectangle shape. In addition, it can be improved much in terms of plants and trees. It is necessary to restore bamboo forest, which was razed in order to make a tea plantation around Seolimdang, to set vines of arbors above the upper limbs, to plant pine trees and willow trees inside of the garden, and to put Dajeolgu under the corner of the eaves. Especially, the bamboo forest emphasized in poetry and took care of by Choeui himself should be restored inside of the garden.