• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.25-34
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• 2008

An application of concrete track is being actively processed for the construction of Korean high speed railway. The concrete track has an advantage in decreasing the maintenance cost, whereas it has much difficulty controlling the long term settlement after settlement occurred. Therefore, the management and control of settlement are very important for the successful construction of concrete track. The purpose of this paper is to verify the allowable settlement between concrete track and ballast track, and piled raft foundation installation effects as settlement reducers for concrete track. Therefore, a series of 3D finite element analyses that take into account the allowable settlement were performed for major parameters such as soil condition, pile installation and loading type. Based on the analysis, it is shown that concrete track causes much smaller settlement than ballast track, and the effect of installation is necessary to effectively reduce the settlement of concrete track.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.29-38
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• 2007

The research on the track performance and stability of the tilting-train was performed and the settlement of the roadbed was estimated as the tilting train was being operated on the rail joint under the allowable velocity subjected to the track performance and the stability of the tilting-train. Since the impact on the continuous welded rail (CWR) induced by the tilting-train loading is different from the impact on the rail joint, it needs to investigate the settlement of the roadbed beneath the CWR. In this study, when the tilting-train is being operated on the CWR under the allowable velocity subjected to the track performance and the stability of the tilting-train, the settlement and bearing capacity of the roadbed beneath the CWR have been evaluated using numerical analysis and compared with those beneath the rail joint. The numerical results show that the settlements of the roadbed beneath CWR and rail joint are amount to 71.2% and 88.8% of the allowable settlement, respectively. And the stresses are amount to 10.4% and 12.1% of the allowable bearing capacity, respectively.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.7-14
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• 2006

The tilting-train being operated in pre-existing rail road has a different running mechanism compared to currently operated trains. Therefore, it needs to investigate the evaluation of the track performance, the stability of the tilting-train in operating condition, and the stability of the roadbed. In this study, when the tilting train is operated in the rail joint with the allowable velocity limited by the track performance and the stability of the tilting-train, the settlement of the roadbed has been evaluated by using numerical analysis. The loading on the ground surface generated by the operating tilting-train generates the settlement of the roadbed. The settlement induced by the tilting-train loading has been compared to the allowable settlement and the factor of safety defined by the ratio of the allowable settlement to the settlement generated by the applied loading is evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.399-409
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• 2018

The mechanically stabilized earth wall (MSEW) of the IPM bridge is an important structure that constitutes the bridge, and supports the horizontal earth pressure and approach slab. Therefore, it is necessary to carefully analyze the settlement of MSEW of the IPM bridge. This study examined the settlement according to the height and ground stiffness on the MSEW on the IPM Bridge. According to the design guideline, the IPM Bridge (2016) was designed to have a height of 4.0 ~ 10.0m and the elastic settlement was calculated. The base area and the grounding pressure of the MSE wall increased linearly with the height, and the elastic settlement also increased linearly. In addition, the stiffness of the foundations satisfying the allowable settlement of the approach slab is a N value of 35 or more. The settlement of finite element analysis was estimated to be smaller than the elastic settlement, and the stiffness of the foundation ground satisfied the allowable settlement of the approach slab above N value of 20. Because the elastic settlement of the MSEW of the IPM Bridge was overestimated, it will be necessary to examine it carefully by finite element analysis.

• Geotechnical Engineering
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• v.13 no.6
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• pp.61-70
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• 1997

Although the load -settlement curve characteristics of embedded piles are different from those of driven piles, for the determination of their allowable loads the same analysis method has been adopted without any considerations. According to the related domestic chi teria, the analysis methods of load-settlement curve have some conflicts among themselves and have several vague points in obtaining the allowable capacity from ultimate or yield capacity. In order to solve those problems, the relevant literatures were reviewed. And also the result of 106 pile load tests was analysed. Analysis result indicates that analysis met hods of the load-settlement curve based on single mathematical curve are not suitable for the general analysis method of load-settlement curves due to their various characteristics. As a result, the appropriate analysis methods and safety factors for the determination of allowable capacity of pile are suggested in this paper.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.211-222
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• 2019

This study evaluates the yield load and allowable bearing capacity of ground in compressive loading tests to confirm the effect of CPR foundation reinforcement. The average compressive strength of the injection materials was higher than the planned compressive strength. Standard penetration tests for each stratum showed that foundation reinforcement improved the average N values, thereby increasing the bearing capacity of the ground. Compressive loading tests on two CPR piles revealed that the total and net settlement due to the maximum load exceed that permissible for the CPR pile diameter. The yield load and allowable bearing capacity calculated by the settlement criterion and the load-settlement curves varied greatly with the method applied. Therefore, it seems to be necessary to determine the optimum value through comprehensive analysis after applying various yield load calculation methods.

• Journal of the Korean Geotechnical Society
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• v.31 no.5
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• pp.67-74
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• 2015

Unlike the primary consolidation settlement, the settlement of ground water lowering is not considered separately because of relatively small residual settlement. But the allowed residual settlement (30 mm) of the concrete track in the high-speed railway may be exceeded due to unexpected excessive ground water lowering. This study analyzed the effect of the settlement according to the ground water level change using finite element analysis of stress-pore pressure coupling model, and compared the analysis results with the measured data. As a result, the range of elasticity modulus satisfying the allowable settlement was proposed, and it is suggested that settlement due to ground water level changes should be reflected in the design.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.87-96
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• 2014

In this paper, reliability analysis was done on the characteristics of consolidation and settlement for the inner temporary dike where a weak ground improvement construction was applied. When the consolidation analysis on the foundation ground was done, the following conclusions were obtained by conducting the stability analysis on the effect of space of drains, the effect of consolidation time, and the residual settlement and differential settlement. When construction was done with a drain space which satisfied 95% probability of reaching a target consolidation in each divided area, the occurrence of a residual settlement was within the range, which did not exceed 10cm. It was shown that there was almost no possibility of the occurrence of differential settlement, which was above the permissible differential settlement slope.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.21-28
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• 2018

Despite a number of studies on consolidation behavior that have been carried out in the Nakdong River estuary in Busan, these are focused on the prediction of final settlement during ground improvement process, and there is almost no research on the long-term settlement occurring after that. For the practical study on the long-term settlement, the field monitored settlement data that measured over 10 years in the Busan new port facilities area were used, and the final settlement and predicted time-settlement line were constituted by hyperbolic function. As a result, the measured settlements depend on the thickness of clayey soils, and the pattern were similar to each other and good agreement with the predicted time-settlement line using hyperbolic method. Also, the settlement in the lower non-improved layer occupied 62-76% of total settlement. Information about above results would be quite helpful to understand the long-term settlement behaviors as well as the non-improved layer's settlement is more careful consideration needed at design phase.

• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.99-114
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• 2005

In Part I of this paper, a conceptual approach of the stress path method was newly proposed for a rational estimation of settlements of saturated clay deposits. A detailed procedure for effective evaluation and use of settlement-related characteristic deformation behaviors was developed in order to provide practicality to the new approach. In this Part II, on the basis of the results of Part 1, the concept of the new approach was embodied in the form of a detailed settlement estimation procedure. The applicability and usefulness of the new procedure were strongly supported by various application examples. In addition, possible errors of other conventional settlement estimation methods were investigated by comparing with the new procedure. Because of its flexible applicability for wide range of field conditions, the new procedure will have great usefulness in the practical side. For example, a reasonable foundation design based on allowable settlement criteria can be easily performed and modification of design factors can be readily reflected even during the subsequent construction stage. Especially, the new procedure will be of great use for preliminary work in a large scale construction site where various structures are planned to be constructed on a nearly identical ground condition.