• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.151-163
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• 2006

This paper presents the interrelationship between undrained static and cyclic shear behavior. Laboratory works were performed through the undralned static and cyclic triaxial test using Nak-Dong River sand. And static triaxial test involved the triaxial extension test for comparison with cyclic shear behavior Cyclic triaxial test was performed with a variety of combination conditions of initial static shear stress $(q_{st})$ and cyclic stress $(q_{cy})$. In this result, the stress path of cyclic shear behavior was correspondent with static shear behavior passing the critical stress ratio (CSR) line because of the development of flow deformation. After that, a failure occurred according to failure line (FL) of static shear behavior. The stress path of cyclic shear behavior showed essentially the same with static shear behavior, although it appears a little different in test method.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.479-484
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• 2000

The reliable estimation of the system parameters and the accurate prediction of the system behavior are important to design tunnel safely and economically. Therefore, the back analysis using the field measurements data is useful to evaluate the geotechnical parameter for tunnel. In the back analysis method, the selection of initial value and uncertainty of field measurements influence significantly on the analysis result. In this paper, to overcome uncertainty of field measurements, we performed the back analysis using the displacement data gained at each step of excavation and support.

• Geotechnical Engineering
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• v.4 no.4
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• pp.19-28
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• 1988

An underground explosion crests shock waves, which propagate to a buried structure through the이 ground. Due to the explosion, very high stresses and large deformation occur in the ground so that the shock waves decay gradually. In this study the numerical simulation of the ground shock attenuation has teen performed. One dimensional wave equation is presented and the finite difference method is applies. A Cap model is adopted to describe the stress-strain behavior of the ground. The results are expressed by the attenuation of the peak stress and the particle vrelocity by the time and the distance.

• Structural Engineering and Mechanics
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• v.4 no.6
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• pp.631-644
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• 1996

Geomaterials such as soil and rock are composed of discrete elements of microstructures with different grains and microcracks. The studies of these microstructures are of increasing interest in geophysics and geotechnical engineering relating to underground space development We first show experimental results undertaken for direct observation of microcrack initiation and propagation by using a newly developed experimental system, and next a homogenization method for treating a viscoelastic behavior of a polycrystalline rock.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.83-92
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• 2000

벽체의 수평변위 중 토체의 침하 및 앵커체 자체의 움직임 등으로 인해 발생하는 mass movement가 타이백 앵커토류벽의 거동에 미치는 영향을 조사하였다. 시공사례에 대한 유한요소 해석을 실시하여 벽체의 변위, 겉보기토압, mass movement 및 앵커 자유장 내에서의 하중 변화를 투적하였다. 유한요소해석법을 이용해 mass movement를 계산, 예측할 수 있었으며, 시공 순서에 따흔 앵커 자유장 내의 하중변화를 예측할수 있었다. 현장계측결과와 유한요소해석결과로부터 벽체변위, 겉보기토압 및 앵커의 하중 변화에 미치는 mass movement의 영향이 매우 큼을 확인 할 수 있었다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.515-518
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• 2010

Horizontal forces may form a major part of the loading system for structures supported on pile groups. It is known that during a strong earthquake, the dynamic behavior of a group-pile foundation is related not only to the inertial force coming from the superstructures but also to the deformation of the surrounding ground. Therefore, it is necessary to understand the behaviors of the group-pile foundations and superstructures during major earthquakes. In this paper, numerical simulation of real-scale group-pile foundation subjected to horizontal cyclic loading is conducted by using a program named as DBLEAVES. In the analysis, nonlinear behaviors of ground and piles are described by cyclic mobility model and axial force dependent model (AFD model). The purpose of this paper is to prove availability of the analysis method by comparing numerical results and test results.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.171-180
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• 2016

Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.103-108
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• 1999

This paper describes development of a new automated real-time system which preforms measurement data reduction and management, geotechnical backanalysis, and feedback design for embankment construction on soft ground. Such a system can be an effective, useful and economical tool for managing a large site development on soft ground. The system consists of data base system to characterize soil properties and identify instrumentation, analysis system for ground behavior and stability coupled with automatic monitoring system, and feedback design system which is a new technique to reflect the analysis of measured ground behavior against original design.

• Geotechnical Engineering
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• v.6 no.4
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• pp.65-74
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• 1990

This paper presents triaxial test (CIVC and CKOUC) results on normally consolidated deep sea clay samples. Based on the test results the pore pressure-strain relations for both isotropicaly and anisotropicaly consgidated samples are expressed with hyperbolic functions of the major princpal strain. The analysis of the difference in pore pressure behavior due to the anisotropy in consolidation stress is carried out with the effective stress pathos of CIVC and CKOUC and finds a factor which correlates the pore pressure of two types of test.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.207-213
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• 2001

Shaking table tests to investigate the dynamic friction behavior of interfaces between dense dry granular soils and construction material(concrete) were performed and the results are reported. The results show the variation of dynamic interface friction coefficients between dense dry granular soils and construction material was small in the sliding velocity range employed in this study. It was also observed that dynamic interface friction coefficients decreased as mean grain sizes of granular soils increased. These coefficients were compared with the friction coefficients obtained from the peak internal friction angles of the same granular soils by plane strain compression tests.