• Advances in concrete construction
• /
• v.11 no.5
• /
• pp.375-386
• /
• 2021

In this paper, a study of stability and health of a newly-built railway tunnel is presented. The field test was implemented to monitor the secondary lining due to the significant cracking behaviors influenced the stability and health of the tunnel structure. Surface strain gauges were installed for monitoring the status of crack openings, and the monitoring outputs demonstrated that the cracks were still in the developing stage. Additionally, adjacent tunnel and poor condition of surrounding rock were identified as the causes of the lining cracking by systematically characterizing the crack spatial distribution, tunnel site and surrounding rock conditions. Reconstruction of partial lining and reconstruction of the whole secondary lining were designed as the maintenance projects for different cracking regions based on the construction feasibility. For assessing the health conditions of the reinforced lining, embedded strain gauges were set up to continuously measure the strain and the internal force of the reconstructed structures. For the partially reconstructed lining, the outputs show the maximum tensile elongation is 0.018 mm during 227 days, which means the structure has no obvious deformation after maintenance. The one-year monitoring of full-section was implemented in the other two completely reconstructed cross-sections by embedded strain gauge. The outputs show the reconstructed secondary lining has undertaken the pressure of surrounding rock with the time passing. According to the calculated compressive and tensile safety factors, the completely reconstructed lining has been in reliable and safe condition during the past year after reinforcement. It can conclude that the aforementioned maintenance projects can effectively ensure the stability and health of this tunnel.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.29 no.3
• /
• pp.1-11
• /
• 2011

Located in Namwon-si, Jeonlla Bukdo, Gwanghallu Garden is created around Gwanghallu, which was a government office in the period of Joseon Dynasty and shows its looks as a government office building of the times. However, Gwanghallu Garden is recognized rather as a background site of Chunhyangjeon, representing a local culture, than the features and picture as a government office garden in the period of Joseon Dynasty because Gwanghallu appeared as the background of Chunhyangjeon in its Chinese character script and, after 1930s, Chunhyang Sadang was built up and Chunhyang Festival held, and it's recognized rather as a site for arousing national consciousness and cherishing Chunhyang for its integrity in the Japanese ruling era of Korea than as a government office building in the period of Joseon Dynasty. With it being more recognized as the background of Chunhyangjeon than an ancient government office building, Gwanghallu has been managed as a private house garden or event place of folk festival as the background of Chunhyangjeon than preserved and managed as ancient government office building, and now the looks and features as a garden of government office are hardly seen because of indiscriminate trees and making of structure and spaces. Therefore, to preserve and maintain Gwanghallu Garden as the garden of government office in the period of Joseon Dynasty, it's required to survey the trees, structure and spaces created in Gwanghallu Garden and compare the true condition with its original looks by studying its literature and it's suggested that the garden area created around Gwanghallu should be repaired and managed by separation from as the background of Chunhyangjeon. Such means of management may keep the looks of Gwanghallu as the ancient office garden while Chunhyangjeon can also settle down as a local culture in the background.

• Economic and Environmental Geology
• /
• v.31 no.1
• /
• pp.59-68
• /
• 1998

Gravity, magnetic and VLF surveys were carried out to investigate the dimension, nature and stability of the waste materials filled in the Seokdae landfill, Pusan. The Seokdae landfill, which is located in a former valley, was used as a dump for mainly domestic-type waste materials for 6 years from 1987. The landfill site is classfied into A, B, C and D areas according to the sequence of dumping period. The Bouguer gravity anomaly map shows maximum variation of 3.1 mgals on the landfill and its general appearance has close relation with the thickness of waste filled. The local variation of anomaly, however, reflect the degree of compactness of waste materials which may be affected by the nature of waste and dumping time. In the case of area A, where dumping process was terminated at the very last stage, most part show negative anomaly compared to other areas. We think that the composition of the waste materials in the area A is high in leftover food and paper trash and they are still in uncompacted condition. In area B, the general trend of variation of gravity anomaly is appeared to be high anomaly in northern part and decrease to the southern part. This is well matched with the prelandfill topography of the landfill site. The southern part of area B is located in the center of valley and its present surface is comparatively rugged, which may be due to the differential settlement of deep burried waste. The thickness of waste in area C is relatively thin, but the gravity anomaly appears to be low. Considering the present condition of surface, it can be inferred that low density wastes such as leftover food were mainly filled in this area. Area D, as in the case of area B, shows gravity anomaly that has close relation with the prelandfill topography. Magnetic data show the variation of total field intensity varies in the range of 46600~51000 nT, and reach maximum anomaly of 4400 nT. The overall pattern of magnetic anomaly well reflects the distribution of magnetic materials in the landfill. The result of VLF survey reveals several low resistivity zones, which may serve as underground passages for contaminant flow, in the area C located near the small Village.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.2
• /
• pp.97-111
• /
• 2013

It is very important to understand the condition of the surround rock for the successful construction of underground space. Representative methods of estimating the rock mass condition are RMR method and Q-system, and they are applied on design, construction, and maintenance. However, many problems with the accuracy of the measurement method and the subjective viewpoint are questioned continuously, so many researchers have been studied for estimating rock condition from various methods. Most of them show only the local relation and a tendency between site investigation data and rock conditions. In this paper, the relationship between RMR method and electrical resistivity is deducted using the analytical equation derived theoretically from electric field analysis on jointed rock mass. And also, probabilistic relationship between RMR method and electrical resistivity is deducted for the increase of accuracy. If a suggested method is applied with the conventional method for estimating the rock condition, it will be helpful to estimate RMR values on the field.

• KIEAE Journal
• /
• v.1 no.2
• /
• pp.63-70
• /
• 2001

With environmental problems and pollutions accumulated by continuous towns or cities developments events, it is becoming necessary to develop in consideration of environmental effects. This consensus leads to prepare a plan system and instrument for ecological city development, which can be a series of planning indicators. To develope a series of process for environmental friendly development, this study has three main goals as follows; development of policies and programs for environmental friendly development, suggestion of environmental friendly urban design models and standards, development of planning indicators and design guidelines Korean land use plan is operated by both zoning system and detailed plan system. But the available kinds of zoning type are too limited to apply to various and vernacular places. In addition to, the detailed plan is understood to be another regulation which constricts the freedom of building right. In this study, Plan System of Environmentally Friendly Space was studied for domestic affairs In German, Plan System of Environmentally Friendly Space is the field have been progressed before. so In this study, example of German was researched intensively, and Plan System of Environmentally Friendly Space was developed, applicable for the real state in domestic. This study was focused on methodology of landscape planning and planning for afforestation. Landscape planning is performed on condition detail investigation of existent state of nature and local characteristic, and Investigation of Planning for afforestation is more detailed than that of Landscape planning. In the basis of methodology of landscape planning and planning for afforestation, Plan for Environmentally Friendly Urban Habitation Model was developed. Plan for Environmentally Friendly Urban Habitation Model was applicable for state of land use planning. Site was selected Chuk-chun in city yang-in, taking the circumstances into consideration. So landscape planning correspond to land use planning was made out. Adjustment of Land use planning and Landscape planning was very important. Undergoing this process, Plan for Environmentally Friendly Urban Habitation Model was performed.

• Geotechnical Engineering
• /
• v.9 no.1
• /
• pp.7-20
• /
• 1993

The first Korean earthquake resistant design code was enacted in 1988. In the code, the soil factor which takes into account both the soil amplification factor and the soil -structare interaction effect is divided into three groups : soil factor, 5 : 1.0, 1.2 and 1.5. In order to assist in choosing the soil factors appropriately in the earthquake resistant design, the local site effects on the based shear force induced by earthquakes are considered in depth for typical soil conditions in Korea. The depth of the alluvial and/or weathered zone is usually not deep and the fresh rock is found at depth shallower than 20 meters, and even at about 10 meters around Seoul. One dimensional wave propagation theory and the elastic half space method are used to obtain the soil -structure interaction effect as well as the soil amplification effect. The kinematic interaction effect due to scattering of waves by pile foundation is also considered. Finally, the soil factor is recommended for each soil condition from loose state to dense, and also from shallow soil depth to deep, so that the designer can choose the factor with-out difficulty.

• Journal of Periodontal and Implant Science
• /
• v.33 no.4
• /
• pp.651-671
• /
• 2003

The influence of calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated two types of titanium implants, i.e. as -machined ,as -machined with Ca-P coating, were prepared. The Ca-P coating produced by OCT Inc technique. These implants were inserted into the left and right femur of beagle dog, After implantation periods of 3 days, 1weeks, weeks, 4weeks, 8weeks, 12weeks. 24weeks, the bone-implant interface was evaluated histologically, histomorphometrically , and removal torque. Histological evaluation revealed no new bone formation around different implant materials after 2weeks of implantation. After 4 weeks, Ca-P coated implants showed a higher amount of bone contact than either of the non coated implants. After 12weeks, bone healing was almost completed. And implant were removed by reverse torque rotation with torque-measuring device. Mean torque values for 4weeks control were 2.375Kgf.cm and experimental were 2.725Kgf.cm. And mean torque values for 8weeks control were 1.25Kgf.cm and experimental were 1.0Kgf.cm On the basis of these findings, we concluded that deposition of a Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase. Besides implant surface conditions the bone response is also determined by local implant site condition.

• Journal of Chest Surgery
• /
• v.30 no.2
• /
• pp.236-240
• /
• 1997

The management of neonate with long gap atresia without a fistula(type A) is complex and controversial. Various esophageal reconstruction include use of native esophagus or replacement with colon, stomach and small bowel. A severe premature male, at 28 weeks gestation weighing 1.2kg, was born with type A esophageal atresia in Chonnam University Hospital. Initial treatment consisted of gastrostomy under the local anesthesia and suctioning of proximal pouch, and than underwent delayed esophageal end to end anastomosis. A minimal leakage and mediastinitis ocurred postoperatively, but was treated by adequate drainage and negative suction from the leakage site through the gastrostomy. The patient was discharged in good general condition and normal weight of 5.4kg after 4 months after the surgery.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.5
• /
• pp.479-490
• /
• 1998

The concentrations of ten inorganic (sodium, chloride, sulfate, ammonia, etc.) and three organic (acetate, formate, and MSA) ions associated with airborne particulate matter were measured from Cheju Island, Korea during the three field intensive campaigns conducted in (1) Sept./oct. 1997 (fall), (2) Dec. 1997 (winter), and (3) April 1998 (spring). The results of our measurements indicated that the concentration levels of most ionic species were decreasing significantly across the three experimental periods. The patterns of concentration reduction were clear as the sum of all cation and anion species changed dramatically across those periods such as 294> 144 > 65 and 193 >96>74 nequiv/m3, respectively. The changes were best explained in terms of the wind rose patterns of the study site. Since our sampling spot is located on the western-end point of Cheju Island, it is likely to reflect the effects of diverse sources such as natural, marine processes during NW and local non-maritime ones during SE winds. .Hence, the periodical changes in ionic concentrations may be accounted for by the comparable changes in wind direction. To further investigate environmental characteristics of these ionic components, correlation analysis was conducted not only between meteorological and ion data but between different ion-pairs. The results of these analyses confirm that the concentration levels of ionic species are strongly affected by wind speed and temperature and that there are certain patterns between ion species to which such effects apply. In light of the significance of the wind rose patterns in the area, we further extended these analyses into four data groups that were divided on the basis of wind direction. The results of these analyses showed that the strength of correlations between important pairs (e.g.:. between windspeed and most of major inorganic species including sodium and chloride) can be ranked on the distribution of major ions are very diverse, depending on data grouping scheme for such analysis. The results of this study thus suggest that environmental behavior of chemical components be analyzed in various respects, rather than simple standard, especially if measurements are made in complex environmental condition under which both natural and anthropogenic effects are competing each other.

• Journal of Korean Society for Atmospheric Environment
• /
• v.21 no.6
• /
• pp.573-583
• /
• 2005

Fugitive dust, which is emitted in the ambient air without first passing through a stack or duct designed to control flow, is frequently generated by means of wind erosion from storage yards at Pohang Steel Wokrs. The size distribution of fugitive dust is mostly in the range of coarse particulate which is deposited as soon as emitted and less harm to human health; however $20\%$ of fugitive dust contains PM 10 known as one of most harmful airborne pollutant. Consequently, effective control and reduction of fugitive dust is strongly requested by the local society, but it is not easy so far because the generation and dispersion of fugitive dust highly depends on meteorological conditions, and it being occurred for irregularity. This research presented a fugitive dust control system for each meteorological condition by providing statistical prediction data obtained from a statistical analysis on the probability of generating the threshold velocity at which the fugitive dust begins to occur, and the frequency occurring by season and by time of the wind direction that can generate atmospheric pollution when the dispersed dust spreads to adjacent residential areas. The research also built a fugitive dust detection system which monitors the weather conditions surrounding storage yards and the changes in air quality on a real-time basis and issues a warning message by identifying a situation where the fugitive dust disperses outside the site boundary line so that appropriate measures can be taken on a timely basis. Furthermore, in respect to the spraying of water to prevent the generation of fugitive dust from the storage piles at the storage yard, an advanced statistical meteorological analysis on the weather conditions in Pohang area and a case study of fugitive dust dispersion toward outside of working field during $2002\∼2003$ were carried out in order to decide an optimal water-spraying time and the number of spraying that can prevent the origin of fugitive dust emission. The results of this research are expected to create extremely significant effects in improving surrounding environment through actual reduction of the fugitive dust produced from the storage yard of Pohang Steel Works by providing a high-tech warning system capable of constantly monitoring the leakage of fugitive dust and water-spray guidance that can maximize the water-spraying effects.