• Proceedings of the Korean Geotechical Society Conference
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• 1993.10a
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• pp.57-62
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• 1993

Settlements of maximum 23cm have occurred in and Apartment building consturcted on a fill layer with pile foundations. The main reason of the settlements was due to the negative skin friction applied to the pile, and settlement of adjacent ground since most pile tips are acted as a floating foundation founded on the stratum where the SPT N value was mostly less than 30. To underpin this building, the Jumbo Special Pile grouging was adopted, and instrumented data showed little differential settlement after the JSP underpinning.

• Geomechanics and Engineering
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• v.16 no.2
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• pp.187-194
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• 2018

Application the pile group foundation to reduce overall settlement of the foundation and also avoid a very fruitful settlement of foundations, inconsistent was carried out. In such a case, in event that the Foundation, not as a mere pile group, which as a system consisting of a broad foundation with pile Group, economic design criteria will be provided in spite of high safety. A new approach in the design of the Foundation can be introduced as the piles are just a tool to improve the parameters of soil hardness; that it can work with detachable piles from raft. Centralized arrangement of piles as the most optimal layout of piles in reducing inconsistent settlement, which is the lowest value of resulting layout in this differential settlement. Using the combination of piles connected and disconnected to form the raft, bending moment created in the raft is reduced. It also concentrated arrangements have greatest effect in reducing amount of moment applied to the raft.

• Geotechnical Engineering
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• v.7 no.1
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• pp.33-40
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• 1991

This paper reports the application study of the ground reinforcement under a pipe joint. The soil-reinforcement interaction helps to minimize the stress concentration at joint. The settlement pattern and the earth pressure variation have been evaluated under the pipeline subjected to differential settlement. The pipeline is fixed at one side with the other side set free being loaded with a uniform surface loading. The problem has been studied by means of laboratory model test and flite element technique, and the analysis results are compared for both non-reinforced and reinforced cases to evaluate the effectiveness of the soil reinforcement for restraining the settlement of the pipeline.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.219-226
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• 2004

We measure subsidences occurred in a reclaimed coastal land, Noksan industrial complex, by using JERS-1 SAR (1996-1998) and RADARSAT-1 SAR (2002-2003) dataset. SAR with a high spatial resolution (about several or several tens meter) can reveal the two-dimensional distribution of settlement that would be bardly estimated from in situ measurements. The DInSAR results show significant deformation signal associated with soil consolidation. Accuracy of the settlements estimated by 2-pass differential interferometry (DInSAR) is evaluated using the measurements of settlement gauge. A two-dimensional subsidence map is constructed from 7 qualified pairs. Comparing the JERS-1 radar measurements with the ground truth data yields the correlation coefficient of 0.87 (RMSE of 1.44 cm). The regression line shows the gradient of 1.04 and intercepts close to the origin, which implies that the unbiased settlement can be measured by DInSAR technique. The residual settlements are also detected from RADARSAT-1 pairs. The extent and amount of the settlements are matched well with ground truth data.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1164-1169
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• 2009

Piled raft foundation is commonly used for structure on deep soft soil deposit rather than end bearing piles to control differential settlement. However, it is still expensive for light weight structures. Wing-wall type foundation has been successfully applied to reduce average settlement for light weight structure. This study will further investigate this type of foundation using bench scale experiments on clay and sand. Numerical analysis and approach method are used to verify load settlement curve of wing-wall foundation on experimentally study. Furthermore, normalized settlement curves are applied to define prediction of settlement on wing-wall foundation. In the result settlement on wing-wall foundation can be effectively done by increasing the length of wall instead of number of walls and equation for calculating average settlement can be derived using normalized load settlement curve.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.85-86
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• 2015

Recently, As the high rise buildings have been demanded due to the rising current of land price, the permanent drainage method have been applied during and after the construction as a way to reduce the buoyancy acting on the bottoms of the foundations in the basement. This method has brought about the consolidation subsidence of the ground and turned out to be the problems of sinking hole and foundation re-settlement. The representative methods to be used for extending the life cycle of the existing building structure which is tilted by the foundation re-settlement or differential settlement of the foundation can be divided into the building structures reinforcement and soil reinforcement. The purpose of this study is to analyze and present the application example of steel pipe pile method to extend the life cycle of the six -stories building tilted in a soft ground.

• Geomechanics and Engineering
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• v.4 no.1
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• pp.67-78
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• 2012

Soil foundations exhibit significant creeping deformation, which may result in excessive settlement and failure of superstructures. Based on the theory of viscoelasticity and fractional calculus, a fractional Kelvin-Voigt model is proposed to account for the time-dependent behavior of soil foundation under vertical line load. Analytical solution of settlements in the foundation was derived using Laplace transforms. The influence of the model parameters on the time-dependent settlement is studied through a parametric study. Results indicate that the settlement-time relationship can be accurately captured by varying values of the fractional order of differential operator and the coefficient of viscosity. In comparison with the classical Kelvin-Voigt model, the fractional model can provide a more accurate prediction of long-term settlements of soil foundation. The determination of influential distance also affects the calculation of settlements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.4
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• pp.217-226
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• 1993

This study is related to the surface subsidence due to the collapse of a underground void during earthquakes. The amount of the settlement due to the collapse of a underground void will depend on the depth of the void, the initial condition of unit weight of sand, the size and type of foundation, the strength of earthquake, the size of a void, etc. The purpose of the paper is to estimate the amount of the subsidence, analyse the factors affecting the subsidence, and develop a program determining the probability of the damages to structures in terms of absolute and differential settlement and rotational settlement. On the base of the results obtained in this study, when the depth of a void is constant and the width of the void increases, the change of the subsidence factor due to the angle of internal friction and the actual effective factor of the void become smaller than that due to the unit weight of sand deposits. In the same condition, the probabilities of damages due to the absolute and differential settlement increase, and those due to the rotational settlement decrease.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1287-1296
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• 2007

Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in about 400km section at 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. In spite of little study for this wetting collapse problem, it has been recognized that the compressibility of compacted sands, gravels and rockfills exhibit low compressibility at low pressures, but there can be significant compression at high pressures due to grain crushing by several researchers(Marachi et al. 1969, Nobari and Duncan 1972, Noorany et al. 1994, Houston et al. 1993, Wu 2004). The characteristics of compression of fill materials depend on a number of factors such as soil/rock type, as-compacted moisture, density, stress level and wetting condition. Because of the complexity of these factors, it is not easy to predict quantitatively the amount of compression without extensive tests. Therefore, in this research I carried out the wetting collapse tests, with focusing in various soil/rock type, stress levels, wetting condition more closely.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.472-485
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• 2008

In this study, sand compaction pile method was adopted to improve the soft ground under the permanent dyke, namely west sea dyke of Incheon New Port. The row replacement ratio 30% was applied to consider the ground condition, environmental side and the construction cost of the site. The stability and displacement analysis was carried out by respectively SLOPE/W and PLAXIS 2D program. Based on this analysis, it is found that the safety factor and displacement is within an allowable criteria. The model experiment was carried out using the acryl soil box with $400(H){\times}1200(L){\times}250(W)mm$ to show the displacement of the dyke and behavior of soft ground. Based on this experiment results, it is found that the settlement does not occur from 1 and 2 loading phases and horizontal displacement of 0.0075% occurs from 2 phases. It is also found that the differential settlement occurs 0.05mm corresponding respectively 0.02% and 0.03% of the dyke height(15cm).