• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.726-733
• /
• 2005

It is very important to pay careful attention to construction of earthwork/tunnel transition zone for railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. In this study, performance of transition zone was investigated through the field tests. The wheel loads and sleeper settlement were measured after installing field testing sections.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.997-1002
• /
• 2009

The local loosening of ballast supporting railway tract cause a differential vertical tract settlement. In the bridge, the temperature change make bridge deck to contract and expand, and this movement cause local loosening of ballast on the bridge expansion joint. Therefore, the evaluation of the status of ballast on the bridge expansion joint is important for the track maintenance of the high-speed railway. In this paper, hwaw method was applied to evaluate the status of ballast on the bridge expansion joint. HWAW method is non-destructive test to evaluate 2-D shear wave velocity map along the railway. Shear wave velocity is directly related with status of ballast. In this research, hwaw method was applied two different types of bridges and determine the degree and the range of the ballast loosening caused by movement of the bridge expansion joint.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.984-996
• /
• 2009

When evaluating the general subgrade states such as geology, stiffness, underground water, compaction and deformation in the Gyeongbu high speed railway, some applicable testing methods should be selected because lots of trains are currently running. The applicable methods includes not only non-destructive tests such as GPR test, electricity resistivity test, MASW proving, but also standard penetration test (SPT), core test, elastic wave tomography through drilling boreholes and measurements using settlement measuring system or inclinometer, etc. In order for evaluating the subgrade states in the Gyeongbu high speed ralway, this study performed GPR test in several sections and drilling boreholes whose locations were chosen after comparing GPR test results and track maintenance history. Furthermore, the progress of subgrade deformations was analysed by comparing previous and this time GPR test results. The results of this study shall be used to understand the general states of currently operating Gyeongbu high speed railway.

• Proceedings of the KSR Conference
• /
• 1998.05a
• /
• pp.137-159
• /
• 1998

For the construction of railroads in Metropolytan area based upon the outcome of the future demand forecast, a total of 21 lines including electrified double track segment of Ui-Jung-Bu↔Dong-Du-Chun(18.9km) in Kyung-Won Line is expected. Considering the financial difficulties and investment effect of the lines, this in the sequel brings about an important matter of deforming priority Investment plan to build electrified lines among the candidates. In the case of Japan, Tokyo metropolytan area covered In total by 2,070.1km of various lines, i.e., subway lines(241km), private lines(952.7km), JR lines(876.4km), provides convenient means of transportation for the coummuters and makes a contribution to the development of its neighboring areas and to the expansion of settlement areas. Comparing the total length per 1,000$\textrm{km}^2$, Tokyo(105), Paris(117), and London(115) are at least 6 times as large as ours(15). The purpose of this study is two fold provide a basic scheme for building railroads in metropolytan area and determine priority order in accordance with some evaluation criteria.

• Journal of Arbitration Studies
• /
• v.23 no.1
• /
• pp.133-152
• /
• 2013

Recently, the United Nations Commission on International Trade Law (UNCITRAL) has made progress toward resolving low value, high volume disputes in international e-commerce. At the Working Group's 26th session, two draft procedural rules were addressed. The first discussed the draft of Article 9, entitled "Decision by a neutral party." This is based on the suggestion in 26th session to have a "two track" system of ODR, one including negotiation, facilitated settlement, and arbitration phrases, and the other not including an arbitration phase. The second draft procedural rule, draft Article 10, regards the language of proceedings. In most cases of international e-commerce, the decision of language of an ODR proceeding is a matter of importance, for the language parties could differ from each other. This paper examines several implications of UNCITRAL for Korea, which has unstable ODR system.

• International Journal of Railway
• /
• v.9 no.1
• /
• pp.15-20
• /
• 2016

An approach section on an abutment is located between the soil embankment and the structure, which may cause an uneven surface due to different settlement between the abutment and the soil embankment. This study proposes a new type of wall which separates the abutment from the backfill material using mechanically stabilized wall. A new type of keystone which incorporates geotube and wire mesh is proposed and evaluated. Numerical analyses were performed to investigate the applicability of the proposed keystone type, which incorporates Geosynthetic. The maximum horizontal displacements along GRS wall faces, settlements at the top of pavement and track bed, and tensile forces applied on geotextiles under traffic loads were investigated. The results of the numerical analysis showed that the proposed wall can be used for highway and high-speed railway abutment.

• Journal of the Korean Society for Railway
• /
• v.17 no.4
• /
• pp.251-259
• /
• 2014

The transition zone between an earthwork and a bridge effect to the vehicle's running stability because support stiffness of the roadbed is suddenly changed. The design criteria for the transition structure on ballast track were not particular in the past. However with the introduction of concrete track is introduced, it requires there is a higher performance level required because of maintenance and running stability. In this present paper, a transition structure reinforced with geosynthetics is suggested to improve the performance of existing bridge-earthwork transition structures. The suggested transition structure, in which there is reinforcing of the approach block using high-tension geosynthetics, has a structure similar to that of earth reinforced abutments. The utilized backfill materials are cement treated soil and gravel. These materials are used to reduce water intrusion into the approach block and to increase the recycling of surplus earth materials. An experiment was performed under the same conditions in order to allow a comparison of this new structure with the existing transition structure. Evaluation items are elastic displacement, cumulative settlement, and earth pressure. As for the results of the real-scale accelerated testing, the suggested transition structure has excellent performance for the reduction of earth pressure and settlement. Above all, it has high resistance the variation of the water content.

• Journal of the Korean Society for Railway
• /
• v.16 no.4
• /
• pp.278-285
• /
• 2013

The suppression of residual settlement is required on earthwork sections as concrete track is introduced. Use of pile-slab structure is one of the settlement restraining methods applied on soft ground. The slab distributes the upper embankment load and piles transfer the load from the slab to the stiff ground. While this method is very effective in terms of load transfer, it has not yet been established for dealing with the vibration transfer effects and interaction characteristics between a structure and the ground. It is possible that vibration caused by a moving train load is propagated in the upper embankment, because the slab acts as a reflection layer and waves are multi-reflected. In this present paper, wave propagation generated by a moving train load is evaluated in the time and frequency domains to consider a roadbed structure using an artificial impact load and field measured train load. The results confirmed the wave reflection effect on the pile-slab structure, if the embankment height is sufficient, vibration propagation can be stably restrained, whereas if the height is not sufficient, the vibration amplitude is increased.

• Journal of the Korean Society for Railway
• /
• v.18 no.2
• /
• pp.117-126
• /
• 2015

The development of railway roadbed for 600km/h train speed level is very difficult because unpredictable static and dynamic interaction occurs between the ultra-high speed train and the infrastructure. Especially, an earthwork-bridge transition zone is a section in which influential factors react, such as bearing capacity, compression, settlement, drainage, and track irregularity; these interactions can include complicated dynamic interaction. Therefore, if static and dynamic stability are secured in transition zones, it is possible to develop roadbeds for ultra-high speed railways. In the present paper, design parameters for transition reinforcement applied to present railway design criteria are analytically examined for ultra-high speed usage on a preferential basis. Design parameters are the presence of reinforcing materials, geometric shape, stiffness of materials, and so on. Analysis is focused on the deformation response of the track and running stability at ultra-high speed.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.2
• /
• pp.45-57
• /
• 2008

The improved turnout system is developed to speed-up the pre-existing railroad. The research has been actively carried out far the improved turnout system and the impact factor is estimated using the data sets achieved from the dynamic wheel-load field tests in both the conventional and the improved turnout system. In this study, the track performance and roadbed behavior are examined for the conventional and improved turnout system using the estimated impact factor. Dynamic wheel load and rail pressure are evaluated to assess the track performance. Roadbed stress and settlements are estimated using numerical analysis. Additionally, the stability of roadbed is estimated in soft roadbed condition influenced by the weather effects and cyclic train loading. The results show that dynamic wheel load, rail pressure, roadbed stress, and roadbed settlements in the improved turnout system substantially decrease compared with those in the conventional turnout system.