• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.21-28
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• 2016

This paper deals with contents on the estimation of rail beam from the geotechnical engineering aspect. Rail beam is reinforced rail installed on the inside and outside of rail to prevent differential settlement during the construction period of railroad crossing construction. Such rail beam is frequently being installed to ensure stability of existing railroad facilities because of increasing constructions of underground structures crossing railroad in recent. However, there is a difficulty in design due to lack of design standard on rail beam length. Furthermore, derailing accidents are also occurring as a result of rail beam length shortage. Accordingly, this paper presented flow chart based on the classification into soil ground and bedrock ground for the rail beam length estimation. In addition, case study was conducted on rail combination and location through which effective rail combination and location were ensured.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.274-281
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• 2014

Since the vibration induced by a train is transferred directly to a station via a roadbed structure, the elevated station is particularly vulnerable to noise and vibration. To establish more appropriate measures to reduce vibration, the structural behavior and damping characteristics depending on the structural type and the composition of a elevated station should be identified, because the noise inside the station is mainly structure borne noise by the vibration of a station structure. In this paper, the vibration characteristic changes depending on mechanical connection types between an elevated station and a connected bridge are analyzed. The finite element model for Daecheon Station is constructed for the purpose of this study, and the analysis is performed using ABAQUS. The analyses are conducted for with and without bridge connections, and for the bridge connections, ramen and bearing types are considered in the analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.34-42
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• 2018

In order to minimize the deformation of asphalt concrete track(ACT) and ensure the structural safety, a wide type concrete sleeper is necessary to distribute vehicle loading and reduce the exposure of the asphalt roadbed. In this research, the wide prestressed concrete(PSC) sleeper for ACT was developed through the shape design and the structural safety was reviewed using finite element analysis. Furthermore, static test, dynamic test and fatigue test were carried out according to EN13230-2 to verify the design appropriateness of the wide PSC sleepers for ACT. The performance test showed that the developed wide PSC sleeper for ACT meets all the performance requirements by European standard.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.192-203
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• 2009

In the new Seoul-Busan high speed railroad construction specially in area of city center passage the roadbed establishment is recommended the staibility for the existing subway tunnel segments of Busan subway 1st and 2nd lines regarding the appearance condition, a quality condition and the durability of the objective facility, and it evaluates the numerical analysis using MIDAS/GTS which leads the stability of the objective facility and investigatesd tunnels. Fundamental issues in tunneling under high groundwater table are discussed and the effect of groundwater on tunnel excavation was examined using a 3D stress-pore pressure coupled Finite-Element Method. Based on the results the interaction mechanism between the tunnelling and groundwater is identified. In the both of 1st and 2nd Line the maximum sinkage, unequal sinkage and the lining stress from numerical analysis are within permission and the damage degree is appearing to be disregarded. But it enforces necessary Pre-grouting in order to minimize an actual tunnel face conduct and when the tunnel is excavated it is also necessary to minimize the outflow possibility.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.797-804
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• 2019

The two Koreas agreed to pursue rail and road connections on September 19, 2018 in the Pyongyang Joint Declaration. In December 2018, they launched a joint investigation for the North Korean railway modernization project. The survey confirmed that the track condition is seriously aging so that it is impossible to operate, and the railway network is well connected to major cities. Therefore, it was reasonable to modernize the aging track of the existing railway network rather than construct a new railway network. This paper proposed the railway communication policy for the improvement of railway lines and the construction of the railway wireless network by analyzing the status of roadbeds and tracks in order to enhance interoperability for the inter-Korean railway connection and safety for preventing the railway accidents.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.489-497
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• 2016

The rail fastening system, which provides a structural connection between the rail and the sleepers, is a main track component that plays an important role in retaining the rail gauge within acceptable tolerances, as well as in passing the train load to the roadbed through the sleepers. In this paper, a modal test was first performed to evaluate the dynamic characteristics (e.g., natural frequency) of the clips of the railway fastening system under the condition of rail corrugation in urban railway operation. The corrugation-induced passing frequency was then compared with the natural frequency of the clips to investigate any resonance effect during train passage. Furthermore, a field test under train passage was conducted to measure the accelerations on the rail and the rail fastening clips as well as the strains on the rail fastening clips in the rail corrugation condition. The field measurements indicated that the accelerations on the rail and the rail fastening clips have a close relationship with the rail corrugation, but they had a minimal effect on the strains of the rail fastening clips.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.75-82
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• 2019

Slab panels are very important to develop asphalt concrete (AC) track for minimizing the roadbed stress due to the train load and reducing the plastic deformation of infrared-sensitive AC. In this study, the slab panel for AC track was developed through the shape design and the indoor performance test and its structural integrity has been investigated through the finite element analysis under the flexural tensile stress and the design moment according to various static load combination by KRL-2012 standard train load model and KR-C code. In order to verify the suitability of the slab panel for AC track, static bending strength test and dynamic bending strength test were performed according to EN 13230-2. Results show that the slab panel for AC track satisfies all the performance standards required by European standards such as crack loads and crack extension.

• Journal of the Korean Geotechnical Society
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• v.37 no.9
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• pp.13-24
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• 2021

Recently, attempts have been made to detect fouling patterns in the ground using Ground Penetrating Radar (GPR) during the maintenance of gravel ballast railway tracks. However, dealing with GPR signal data obtained with a large amount of noise in a site where complex ground conditions are mixed, often depends on the experience of experts, and there are many difficulties in precise analysis. Therefore, in this study, a numerical modeling technique that can quantitatively simulate the GPR signal characteristics according to the degree of fouling of the gravel ballast material was proposed using python-based open-source code gprMax and RSA (Random sequential Absorption) algorithm. To confirm the accuracy of the simulation model, model tests were manufactured and the results were compared to each other. In addition, the identification of the fouling layer in the model test and analysis by various test conditions was evaluated and the results were analyzed.

• Journal of the Korean GEO-environmental Society
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• v.22 no.4
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• pp.5-13
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• 2021

The transition is the zone where support stiffness suddenly increases in the railway industry. If the support stiffness increases, differential settlement will occur at the transition due to difference of stiffness, and the differential settlement causes problems for the train running safety and the roadbed that supports the track. In particular, a study on differential settlement at bridge-earthwork transition was only conducted to considering railway load in most cases. However, these studies have not taken account of earthquake despite earthquake has been occurred frequently in the recent, and it is necessary to consider earthquake. Therefore, in this study numerical analysis has been performed by changing the inclination of approach block, which determines the shape of the transition, and earthwork in order to verify the effect of the shape of the transition on the dynamic behavior at the bridge-earthwork transition. The result shows that the dynamic behavior at the bridge-earthwork transition was affected by the shape of transition.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.151-163
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• 2021

This paper is dealt with railway slope stability for slope reinforcement using a geosynthetic concrete composite mat(GCCM). Recently, according to a change in weather caused by global warming, train operation has been restricted by the loss of backfill slope at the roadbed, which is consists of gravel, due to typhoons and heavy rainfall. In addition, the amount of damage is getting more significant than the cost of restoration, and the safety of workers is worried. In order to improve this limitation, a slope stability analysis was applied with a rapid hardening composite mat so that it can quickly secure a construction surface with increased workability and work stability and reduce maintenance costs by preventing re-loss in case of heavy rain and fundamentally blocking vegetation. As a result of the analysis, it was confirmed that the increase in safety factor was confirmed when the rapid harding composite mat was applied.