• Journal of Korean Society of Transportation
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• v.21 no.5
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• pp.73-81
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• 2003

The Government presented improvement plans such as "Traffic Accident Frequent Point" and "Hazardous Roads" to reduce traffic accidents on the increase after 1980s. In case of the hazardous roads, they are expressed by grades which are marked by geometric elements such as width, radius, grade. sight distance. and other environmental factors. As each business for improving roads goes by only focusing on improvement of geometric elements, excessive expense can be invested too much nowadays causing economical waste. Therefore, as improvement plans approached by economic access are needed, this paper shows the cost-effective improvement of the business to keep safety related to traffic accident and economical waste. The hazardous roads which authorized by Gwang-ju National Road Preservation Office of Construction and Transportation Ministry in 1995 for business for improvement of roads, were investigated before 1999. First of all, estimating traffic accident models are presented by using existed data statistically. The models help to maximize traffic accident decrease through control of the presented factor. Secondly, optimum construction cost of improvement is presented to prevent overcapitalization. However, this paper is limited because it was difficult to sort the data with various areas and to approach various ways.

• Explosives and Blasting
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• v.26 no.2
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• pp.38-44
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• 2008

Recently, planning road construction in South Korea is focused on upgrading of the existing road by rerouting or restructuring. For this, roads under current construction in Korea go for more straight in its alignments and routing. Straight routing makes it all the more required to construct many mountain tunnels and bridges in Korea where mountains are so widely spread. Some portal of mountain tunnel is not rarely planed at high steep slope of mountain valley where it is not easy to secure working space for tunnel excavation. Reverse excavation is an alternative measure for excavation of tunnel portal at high steep slope. Construction in reverse excavation method has three important points requiring careful consideration: 1)planning of pilot tunnel in proper width, height, and length etc., 2)measure against the effect of one-side earth pressure to the direction of tunnel portal, 3)securing tunnel safety against shallow ground condition at portal zone. This paper intends to suggest applicable range of pilot tunnel for reverse excavation at the portal zone located at high steep slope, and shows result of study on the appropriateness of a reverse excavation by means of 3D numerical analysis. Result of 3D numerical analysis for reverse excavation at high steep slope shows that pilot tunneling will be applicable to start from the point $20{\sim}25m$ before the portal from inside the tunnel.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.786-792
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• 2010

This paper presents a real-time lane detection method which can accurately find the lane-mark boundaries in complex road environment. Unlike many existing methods that pay much attention on the post-processing stage to fit lane-mark position among a great deal of outliers, the proposed method aims at removing those outliers as much as possible at feature extraction stage, so that the searching space at post-processing stage can be greatly reduced. To achieve this goal, a grid-based morphology operation is firstly used to generate the regions of interest (ROI) dynamically, in which a directional edge-linking algorithm with directional edge-gap closing is proposed to link edge-pixels into edge-links which lie in the valid directions, these directional edge-links are then grouped into pairs by checking the valid lane-mark width at certain height of the image. Finally, lane-mark colors are checked inside edge-link pairs in the YUV color space, and lane-mark types are estimated employing a Bayesian probability model. Experimental results show that the proposed method is effective in identifying lane-mark edges among heavy clutter edges in complex road environment, and the whole algorithm can achieve an accuracy rate around 92% at an average speed of 10ms/frame at the image size of $320{\times}240$.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.5-15
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• 2012

Field monitoring data for embankments in thirteen road construction sites at coastal area of the Korean Peninsula were analyzed to investigate the characteristics of lateral flow in soft grounds, to which vertical drain methods were applied. First of all, the effect of the embankment scale on the lateral flow was investigated. Thicker soft soils and lager relative embankment scale produced more horizontal displacements in soft grounds. Especially, if thick soft grounds were placed, the relative embankment scale, which was given by the ratio of thickness of soft ground to the bottom width of embankments, became larger and in turn large horizontal displacement was produced. And also higher filling velocity of embankments induced more horizontal displacements in soft grounds. The other major factors affecting the lateral flow in soft ground were the thickness and undrained shear strength of soft grounds, the soil modulus and the stability number. Maximum horizontal displacement was induced by less undrained shear strength and soil modulus of soft grounds. Also more stability numbers produced more maximum horizontal displacements. When the shear deformation does not develop, the stability number was less than 3.0 and the safety factor of bearing was more than 1.7. However, if the stability number was more than 5.14 and the safety factor of bearing was less than 1.0, the unstable shear failure developed in soft ground. 50mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear deformation in soft ground, while 100mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear failure in soft ground.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.649-661
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• 2020

Cut-slope management system (CSMS) has been investigated all slopes on the road of the whole country to evaluate risk rating of each slope. Based on this evaluation, the decision-making for maintenance can be conducted, and this procedure will be helpful to establish a consistent and efficient policy of safe road. CSMS has updated the database of all slopes annually, and this database is constructed based on a basic and detailed investigation. In the database, there are two type of data: first one is an objective data such as slopes' location, height, width, length, and information about underground and bedrock, etc; second one is subjective data, which is decided by experts based on those objective data, e.g., degree of emergency and risk, maintenance solution, etc. The purpose of this study is identifying an data application plan to utilize those CSMS data. For this purpose, logistic regression, which is a basic machine-learning method to construct a prediction model, is performed to predict a judging-type variable (i.e., subjective data) based on objective data. The constructed logistic model shows the accurate prediction, and this model can be used to judge a priority of slopes for detailed investigation. Also, it is anticipated that the prediction model can filter unusual data by comparing with a prediction value.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.87-96
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• 2015

Geosynthetics are widely used in different ways such as reinforcement of structures in road, railway, harbor and dam engineering, drainage, separation and erosion prevention. They are especially applied to reinforced retaining wall and slope or ground reinforcement. Recently, geosynthetics reinforced pile supported (GRPS) embankment was developed to improve stability and construability of embankments in railway engineering. Extension strains are usually measured by strain gauges adhered to geosynthetics to evaluate the stability of geosynthetics. However, the measurements are influenced by manufacturing method and stiffness of geosynthetics and also adherence of strain gauge. In this study, wide-width tensile strength tests were performed on three types of geosynthetics including geogrid, woven geotextile and non-woven geotextile. During the test, strains of geosynthetics were measured by both video extensometer and strain gauges adhered to the geosynthetics and the measured results were compared. Results show that the measured results by strain gauges have high reliability in case of large stiffness geosythetics like geogrid and woven geotextile, whereas they have very low reliability for small stiffness geosythetics like non-woven geotextile.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.13-22
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• 2009

The study area is a tunnelling section passing through the Yangsan Fault zone. Kyungbu express highway and national road 35 are located above the tunnel. Previous study showed that fault gouge and fault breccia were widely distributed in the tunnelling section with a maximum width of 100 m. From the present study, it is found that sedimentary rocks consisting mainly of shale are distributed at the eastern block of the Yangsan Fault and these rocks are not subject to mechanical fracturing and hydrothermal alteration. On the other hand, dacitic tuff distributed at the western block of the Yangsan Fault is largely affected by mechanical fracturing and hydrothermal alteration. The large fault zone of $50{\sim}130m$ width was formed by complex processes of mechanical fracturing and hydrothermal alterations such as chloritization, sericitization, and kaolinization. Based on the characteristics of mechanical fracturing and hydrothermal alterations, the Yangsan fault zone in the study area is geotechnically classified as four zones: unaltered zone, altered zone, altered fractured zone, and fault gouge zone. These zones show different degrees and aspects in mechanical fracturing and hydrothermal alterations, resulting in different engineering properties.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.63-72
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• 2007

The purpose of this study is to develop a traffic characteristic analysis, a correlation analysis with the variables of traffic characteristics, and accident estimation models while recognizing the seriousness of the traffic accidents. The analyses deal with the 181 4-legged signalized intersections that accounted for 1,183 out of 3,115 accidents in Cheongju in 2004. After measuring ADT, intersection area, average lane width, elevation, and other items as independent variables and the number of traffic accidents, the traffic accident rate (accidents per million entering vehicles) and equivalent property damage only (EPDO) figures as dependent variables which are estimated as influencing signalized intersection accidents, the estimation models are developed using correlation analysis and multiple regression analysis. In the analysis of the number of traffic accidents, the model indicates an $R^2$ of 0.612, and five independent variables are taken as significant factors. In the analysis of traffic accident rates, the model indicates an $R^2$ of 0.304 and five significant factors, including intersection area and ADT. Also, for the analysis or the EPDO numbers, which coincides with understanding the seriousness of the traffic accidents and the traffic characteristic analysis, the model indicates an $R^2$ of 0.559, and four independent variables (ADT, main street average lane width, elevation, and speed limit) as significant factors.

• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.2
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• pp.28-36
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• 1979

One of most important problems in the Monsoon Asia today is the production of rice paddy to meet the needs of the ever increasing population. Diversemeans are being employed to meet this demand, both by increasing productivity of existing farm land and by bringing further areas into cultivation. The primary step in either field is to ensure that there is sufficient moisture in the soil to suit the paddy, and at the same this means that excess moisture has to be drained off the land, while in others irrigat ion has to be employed to bring sufficient water to an area. In view of the fact that the project comprises a huge amount of earthwork, it can be carried out by extensive use of construction machinery in order to shorten the period. As farm ditch has a comparatively small section with shallow cutting depth, inaddition, there is lack of access road in the field, the excavation equipment with bulldozer or tracter-shovel (backhoe) type are not applicable because there are mostly adapted for the excavation of deep and wide section. Mini-backhoe with its bucket width not larger than 0. 3m, and width of blade not larger than 1. 00m seems to be more adaptable. About 80% of excavation of ditch section will be done by the machinery while the other 20% of excavation together with the finishing of the section are supposed to be done by man-power. The embankment of ditch section can be compacted by the crawler of backhoe when it is moving along the ditch for excavation. However, Lowland paddy field in the Monsoon Asia are made particulary in rain season, therefore, heavy machinery is not easy excavation for ditch. It is very important to know exact ground support power of the working site and select machines with corresponding ground pressure. Ground support power is variable subject to quality and water content of soil and therefore selection of machines should be made duly considering ground condition of the site at the time of construction works. Farm ditches dug and compacted by mannual labar are of poor quality and subject to destruction after one or two years of operation. On the other hand, excavation and compaction by bulldozer is not practical for ditches. Backboe is suitable for slope land, but this is required cycle time of bucket excavation and dumped out. If a small-scale farm ditch trencher adaptable to lowland paddy field is invented, such a machine could greatly accelerate the massive construction work envisaged in many countries and thus significantly speed up the most difficult part of irrigation development and management in Monsoon Asia.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.101-110
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• 2010

In this paper, it has been studied about the CRCO to maintain or rehabilitate the aged JCP. The CRCO and JCO was constructed at useless section of Seo-Hae-Ahn express highway in South Korea. The performance evaluation was conducted. Especially, it was focused on the roll of longitudinal reinforced steels inserted into the CRCO. On crack survey results from field construction section, the reflection cracks at joint of the existing pavement occurred in CRCO. However, due to the constraints of longitudinal reinforced steels, crack width was small. Total crack length and quantity in the CRCO more than that in the JCO. And crack spacing in the CRCO was narrower than it in the CRCP. Through the bonding strength test results, if the cold milling and cleaning as well as surface treatment is applied, there will be no debonding problem at interlayer in the early age. From analysis of the horizontal behavior at the joint, the longitudinal reinforced steels constrained crack width which became wider than initial state over time. Also, that steel in the CRCO reduced the horizontal movement due to temperature variation(4 times than that in the JCO). But, if interface is debonded, the roll decreased. Vertical VWG data showed that CRCO did not occur debonding problem at steel location, but there was some problem in JCO. It was confirmed by field coring. The tensile strain appeared in the CRCO, But the compressive strain occurred in the JCO in early age. Through the FWD test result, deflection in the CRCO was less than that in the JCO. And K value in the CRCO was greater than it in the JCO.