• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.469-476
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• 2002

There are many methods to accelerate for consolidation of the soft ground but, in this study, only preloading method was used to improve the soft ground. To measure the settlement of soft ground, surface-settlement plates were installed at several points. To examine settlement behavior of soft ground, back analysis was done using the measured results. In the back analysis, consolidation parameter( $c_{v}$) were obtained and it was compared with test result for undisturbed sample.e.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.1059-1064
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• 2002

The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The load-deformation characteristics of ground and support are derived by the interaction between ground and support. The interaction between ground and support is qualitatively illustrated by a ground response curve. The behavior of an opening and the performance of support system depend upon the load-deformation characteristics of ground and support as well as of the manner and of timing of support installation. The interaction between ground and support is qualitatively illustrated by a ground response curve. The convergence-confinement method don't need the basic assumptions for a mathematical model. Also This is applicable to general tunnel. Consequently the stability of tunnel must be qualitatively investigated by a ground response curve and quantitatively adjudged by a numerical analysis for the reasonable design of tunnel.

• Earthquakes and Structures
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• 제10권5호
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• pp.1213-1232
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• 2016

This paper investigates the response of nonstructural components in the presence of nonlinear behavior of the primary structure considering the near-fault pulse-like ground motions. A database of 81 near-fault pulse-like ground motions is used to examine the effect of these ground motions on the response of nonstructural components. For comparison, a database of 573 non-pulse-like ground motions selected from the PEER database is also employed. The effects of peak ground velocity (PGV), maximum incremental velocity (MIV), primary structural degrading behavior and damping of nonstructural components are evaluated and discussed statistically. Results are presented in terms of amplification factor which quantifies the effect of inelastic deformations of the primary structure on subsystem responses. The results indicate that the near-fault pulse-like ground motions can significantly increase the amplification factors of nonstructural components with primary structural period and the magnitude of increase can reach 17%. The effect of PGV and MIV on amplification factors tends to increase with the increase of primary structural ductility. The near-fault pulse-like ground motions are more dangerous to components supported by structures with strength and stiffness degrading behavior than ordinary ground motions. A new simplified formulation is proposed for the application of amplification factors for design of nonstructural components for near-fault pulse-like ground motions.

• 화약ㆍ발파
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• 제15권1호
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• pp.44-60
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• 1997

지하공동의 설계는 지반이 본래 가지고 있는 물리적 특성을 최대한 이용하는 것을 기본 개념으로 하므로 지반자체의 복잡다양한 역학적 특성들을 평가하여 설계에 반영하는 것은 지극히 어려운 일이며, 이러한 특성들을 일률적으로 평가하는 것도 거의 불가능하다. 컴퓨터의 발달과 수치해석 기술의 적용이 본격화 되기까지는 지반의 거동을 지배하는 몇가지 주요 요소의 정성적 혹은 정략적 특성에 의하여 지반을 몇가지 등급으로 분류하여 통계자료의 분석 및 경험적 판단에 의해 설계를 수행하여 왔다. 지하공동구조물 설계시의 지반거동해석은 이완영역의 가정에 의한 방법, 경험적 접근법에 의한 방법 및 최근에 와서 수치해석 기술의 발달에 따라 주로 사용되는 공학적 해석 방법에 의한 지반거동해석 등으로 구분하여 정리하였다.

• 지질공학
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• 제1권1호
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• pp.38-53
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• 1991

지하공동의 설계는 지반이 본래 가지고 있는 물리적 특성을 최대한 이용하는 것을 기본 개념으로 하므로 지반자체의 복잡다양한 역학적 특성들을 평가하여 설계에 반영하는 것은 지극히 어려운 일이며, 이러한 특성들을 일률적으로 평가하는 것도 거의 불가능하다. 컴퓨터의 발달과 수치해석 기술의 적용이 본격화 되기까지는 지반의 거동을 지배하는 몇가지 주요요소의 정성적 혹은 정량적 특성에 의하여 지반을 몇가지 등급으로 분류하여 통계자료의 분석 및 경험적 판단에 의해 설계를 수행하여 왔다. 지하공동구조물 설계시으 지반거동해석은 이완영역의 가정에 의한 방법, 경험적 접근법에 의한 방법 및 최근에 와서 수치해석 기술의 발달에 따라 주로 사용되는 공학적 해석 방법에 의한 지반거동해석 등으로 구분하여 정리하였다.

• Geomechanics and Engineering
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• 제7권2호
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• pp.165-181
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• 2014

In the past decade, different types of underreamed ground anchors have been developed for substructures requiring uplift resistance. This article introduces a new type of umbrella-shaped anchor. The uplift behavior of this ground anchor in clay is studied through a series of laboratory and field uplift tests. The test results show that the umbrella-shaped anchor has higher uplift capacity than conventional anchors. The failure mode of the umbrella-shaped anchor in a large embedment depth can be characterized by an arc failure surface and the dimension of the plastic zone depends on the anchor diameter. The anchor diameter and embedment depth have significant influence on the uplift behavior. A finite element model is established to simulate the pullout of the ground anchor. A parametric study using this model is conducted to study the effects of the elastic modulus, cohesion, and friction angle of soils on the load-displacement relationship of the ground anchor. It is found that the larger the elastic modulus and the shear strength parameters, the higher the uplift capacity of the ground anchor. It is suggested that in engineering design, the soil with stiffer modulus and higher shear strength should be selected as the bearing stratum of this type of anchor.

• Structural Engineering and Mechanics
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• 제11권6호
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• pp.651-662
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• 2001

In order to investigate the seismic behavior and seismic design methods in the transverse direction of a shield tunnel, a series of model shaking table tests and a two-dimensional finite element dynamic analysis on the tests are carried out. Two kinds of static analytical methods based on ground-tunnel composite finite element model and beam-spring element model are proposed, and the validity of the static analyses is verified by model shaking table tests. The investigation concerns the dynamic response behavior of a tunnel and the ground, the interaction between the tunnel and ground, and an evaluation of different seismic design methods. Results of the investigation indicate that the shield tunnel follows the surrounding ground in displacement and dynamic characteristics in the transverse direction; also, the static analytical methods proposed by the authors can be used directly as the seismic design methods in the transverse direction of a shield tunnel.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.239-248
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• 2006

The interaction between ground water and structure is complicated behavior which cannot be easily investigated In the laboratory and monitored in the fields. In this study numerical simulation of the interactive behavior was performed using sophisticated coupled-finite element method. Hydraulic behavior of structure is modeled using solid elements with finite Permeability. Recovery of ground water table in the long-term is considered by controlling hydraulic boundary conditions. The results showed that the interaction effect is significant. Particularly non-symmetry in the lining permeability resulted in highly unbalanced pore water pressure which may cause detrimental effects on inner linings of tunnels acting as drains.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.442-447
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• 2002

When a SAR system operates in a full-polarimetic mode, the amount of the information one can extract is so complex that the effective presentation of the information is important. However, the information acquired from the polarimetric SAR data is often difficult to interpret by itself, because it is consisted of both the amplitude information and the phase information. Polarimetric parameters are the good way of representing the polarimetric SAR information in a quantitative manner. Also they can characterize the scattering behavior of the ground scatterer. In this research, extraction of polarimetric parameters, evaluation and interpretation of the scattering behavior of the ground with respect to polarimetric SAR signal are carried out. Using the NASA/JPL AIRSAR data, we estimated the polarimetric parameters and compared them in terms of the ground features. In general, extracted parameters well represent the characteristics of the different features on the ground.

• 한국안전학회지
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• 제23권6호
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• pp.131-137
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• 2008

SCP(Sand Compaction Pile) method that forms a composite ground by driving compacted sand piles into the soft ground. This method is one of the soil improvement techniques for reinforcing and strengthening soft ground deposits. This thesis describes the investigation on the behavior of soft ground reinforced with SCP by low improvement ratio. Direct shear test and consolidation test carried out to verified behavior of composite ground reinforced with SCP. Test results were discussed with reference to the amount of consolidation settlement, variation of shear resistance with area replacement ratio and effect of the stress concentration. And, laboratory model loading test carried out to verified the effect of the location and failure mode of reinforced embankment. Residual shear strength varies with the area replacement and constrict load in the low replacement ratio. Calculated stress concentration ratio overestimate than proposed valve by experimental, theoretical and analytical method. As regards the location, improving right below of the top of the slope was more effective than below of the toe of the slope. This thesis carried out to obtain fundamental information of behavior of the composit ground. Hereafter, centrifuge test that reproduce stress state of the in-situ must be necessary through the further study about pile penetration, reinforce position and construct time.