• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1455-1460
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• 2005

This paper presents the results of an experimental study on the ground deformation by trench excavation for Diaphragm Wall construction. The model tests are performed to investigate the back ground deformation by lowering of slurry level in trench after excavating. Through these, the deformation characteristic of the back ground due to stress release of excavated space was investigated. This study considered relative density of soil mass and the distance between trench and surcharge. An experiment was performed in order to observe the failure pattern of a slurry-supported trench excavated in sandy ground. From model tests, in order to predict reasonably the deformation behavior of the adjacent ground due to the underground excavation, it is significantly recommended that the ground settlement by trench excavation should be considered.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.357-364
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• 2000

This paper starts with reviewing general patterns of deformation of the soft ground with by embankment. Correlation between lateral and vertical deformation of soft ground under embankment are analyzed and discussed by comparing the performance of the Yangsan test embankment on treated soft ground with vertical drains.

• 한국농공학회지
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• 제42권5호
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• pp.78-83
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• 2000

When a sea-dike is constructed on soft soils, it is much difficult to calculate ground deformation caused by forced displacements. In this study , a series of laboratory model tests have been performed to investigate the ground deformation under a constructed sea-dike on soft soils. Construction sequence of sea-dike embankment was assumed such as constructed by quarry first and followed by soils adjacent to quarry embankment. as test data and displacement in subsoils have been analyzed, it seems that deformation is caused by general shear failure. the shape of ground deformation caused by forced displacements was well defined be parabola . Upon comparing profiles and depth of forced displacement from the model test to those based on stress-baring capacity method commonly used, it has been found that deformation prediction using stress-bearing capacity method was not exact at the edge of loading.

• 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.

• 지질공학
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• 제21권2호
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• pp.117-124
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• 2011

해안 매립 연약지반상에 도로나 제방을 성토한 경우 연약지반 속에서는 침하, 융기, 측방유동 등의 지반변형이 빈번하게 발생한다. 연약지반의 지반변형 거동을 지상에서 원지반을 훼손하지 않고 조사하기 위하여 전기비저항탐사법을 적용하여 보았다. 본 연구에서 해안지역의 점토질 퇴적층이 주로 분포하는 서해안 시화지구의 매립지역에서 실험성토를 실시하였다. 실험성토후, 성토하중에 의한 연약지반의 변형 영향범위를 확인하기 위하여 전기비저항탐사법을 실시한 결과, 수평방향으로는 성토 지역에서 남측으로 약 5 m 범위, 수직 방향으로는 지표해 약 5~6m로서 성토 높이의 약 1.0~1.2배 심도까지 높은 전기비저항으로 성토의 영향을 받는 것으로 나타났다. 본 연구결과 성토에 의한 연약지반의 변형을 해석하는데 전기비저항탐사 방법을 적용이 가능한 것을 확인하였다.

• 한국지진공학회논문집
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• 제25권1호
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• pp.11-20
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• 2021

The seismic deformation method is conventionally used as a seismic design for a multi-utility tunnel in Korea. In the seismic deformation method, the soil ground's natural period is one of the most critical factors for calculating the ground displacement using cosine functions. Correction factors for the natural period and shear wave velocity have been used to consider the non-linearity of dynamic soil properties. However, the correction factors have been issued because the correction factors have not been sufficiently studied to consider Korea's regional conditions. This paper aims to evaluate the natural periods for the seismic deformation method considering Korea's ground conditions. Ground response analysis was performed using seven real earthquake records on twelve sites with different soil conditions where actual multi-utility tunnels are installed. As a result, natural periods of the sites were analyzed and new correction factors were proposed according to seismic performance and Korea's regional conditions.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.265-268
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• 2008

The safety of a tunnel under seismic motion is most often evaluated by ovalling deformation of tunnel. This paper research about tunnel's longitudinal deformation. Because of spatial variation of seismic ground motion, the longitudinal structures like tunnel are likely to experience relative displacements along longitudinal direction. The spatially variable ground motion can be estimated by coherency function obtained empirically, and can be considered from different arrival times of ground motion. As a result of estimating tunnel's relative displacements at maximum curvature of tunnel, the displacements and curvatures estimated by coherency function affect the tunnel's safety more than different arrival times. However, if tunnel's displacements by coherency function superpose on displacements by different arrival times, the relative displacements and curvatures of tunnel will be more severe. Therefore, to estimate accurately tunnel's deformation in longitudinal direction has to consider both coherency and wave passage effects.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.285-293
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• 2021

The construction of underground structures such as power supply lines, communication lines, utility tunnels has significantly increased worldwide for improving urban aesthetics ensuring citizen safety, and efficient use of underground space. Those underground structures are usually constructed along with vertical cylindrical shafts to facilitate their construction and maintenance. When constructing a vertical shaft through the open-cut method, the walls are mostly designed to be flexible, allowing a certain level of displacement. The earth pressure applied to the flexible walls acts as an external force and its accurate estimation is essential for reasonable and economical structure design. The earth pressure applied to the flexible wall is closely interrelated to the displacement of the surrounding ground. This study simulated stepwise excavation for constructing a cylindrical vertical shaft through a centrifugal model experiment. One quadrant of the axisymmetric vertical shaft and the ground were modeled, and ground excavation was simulated by shrinking the vertical shaft. The deformation occurring on the entire ground during the excavation was continuously evaluated through digital image analysis. The digital image analysis evaluated complex ground deformation which varied with wall displacement, distance from the wall, and ground depth. When the ground deformation data accumulate through the method used in this study, they can be used for developing shaft wall models in future for analyzing the earth pressure acting on them.

• 한국지반환경공학회 논문집
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• 제17권8호
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• pp.39-44
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• 2016

도심지와 같이 공사 현장에 인접 구조물이 많은 경우, 지반 구조물의 안정성 확보와 더불어 지반의 변형 역시 엄격하게 관리해야 한다. 따라서 공사 중 현장에서 발생하는 지반의 침하를 정확하게 계측하는 것은 매우 중요하다. 지반의 침하는 침하계를 이용하여 계측하는 것이 일반적이나, 최근 전자기술의 발달로 3차원 스캔이 가능한 장치들을 지반 침하 계측에 사용하고 있다. 그러나 이 3차원 스캔장치의 경우 지반 침하의 전체적인 양상을 평가하기는 용이하나 직접 침하를 측정하지 않아 정밀도에 있어서 한계가 있다. 또한, 침하계의 경우 침하계가 설치된 지점에서만 침하값을 측정하기 때문에 전체적인 침하의 양상을 평가하는 데는 한계가 있다. 본 논문에서는 침하계가 측정한 값과 스캐너가 측정한 값을 합성하는 조건부 합성 기법에 대해 연구하였다. 가상의 침하양상과 이를 바탕으로 가상의 스캔한 침하 양상을 생성시켜 연구를 진행하였다. 조건부 합성을 통해 침하 양상의 오차를 획기적으로 줄일 수 있는 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.631-644
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• 2012

Current seismic codes require from the seismically designed structures to be capable to withstand inelastic deformation. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformation and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the performance-based seismic design through capacity-spectrum methods. In this paper, the median of the ductility demand ratio for 80 ground motions are presented for different levels of normalized yield strength, defined as the yield strength coefficient divided by the peak ground acceleration (PGA). The influence of the post-to-preyield stiffness ratio on the ductility demand is investigated. For fixed levels of normalized yield strength, the median ductility versus period plots demonstrated that they are independent of the earthquake magnitude and epicentral distance. Determined by regression analysis of the data, two design equations have been developed; one for the ductility demand as function of period, post-to-preyield stiffness ratio, and normalized yield strength, and the other for the inelastic deformation as function of period and peak ground acceleration valid for periods longer than 0.6 seconds. The equations are useful in estimating the ductility and inelastic deformation demands for structures in the preliminary design. It was found that the post-to-preyield stiffness has a negligible effect on the ductility factor if the yield strength coefficient is greater than the PGA of the design ground motion normalized by gravity.