• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.311-320
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• 2003

The coefficient of consolidation of clay deposit is one of the most important properties in the design of ground improvement. The in-situ value of $c_h$ is generally estimated by pore pressure dissipation using piezocone. Many researchers have suggested theoretical formula for its estimation. This study attempts to find out the validity of the existing theoretical formula in Korea and to find out the characteristics of $c_h$ related to the mechanical properties of clay. Piezocone tests and laboratory tests were performed at the site of pilot project of ground improvement at Yangsan-Mulgeum, Gyeongnam. Comparison of the estimated values of $c_h$using piezocone tests results and those from laboratory consolidation tests are carried out. Results show that Torstensson(cylindrical cavity theory) and Teh & Houlsby solutions derive similar values of $c_h$. And $c_h$ from oedometer test shows values similar to the above two methods. The value from either of the above two methods[Torstensson(cylindrical) or Teh & Houlsby] is recommended to be used as $c_h$.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.2
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• pp.119-128
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• 1999

본 연구는 등방탄성체에 고속충격하중이 작용하는 경우에 대한 유한요소해석에 관한 것으로 대상구조는 여러 가지 모양의 2차원 평면구조를 택하였다. Galerkin 방법을 이용하여 유한요소 정식화하였으며 직접시간적분법에 의해 수치해를 구하였다. 본 해석에서는 균열이 없는 평판으로 수치해와 이론해를 비교하여 수치해의 신뢰성을 확인하였으며, 0°, 30°, 45°경사 균열이 없는 평판에 적용한 3가지 예를 분석하였다. 수치해석 결과는 이론해의 결과와 상호 잘 일치하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.2
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• pp.95-103
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• 2007

An analytical closed-form solution for wave propagation velocity and damping in saturated porous media is presented in this paper The fully coupled field model with compressible solid Brains and pore water were used to derive this solution. An engineering approach for the analysis of fully saturated porous media was adopted and closed-form solutions for one dimensional wave propagation in a homogeneous domain were derived. The solution is highly versatile in that it considers compression of the solid grains, compression of the pore water, deformation of the porous skeleton, and spatial damping and can be used to compute wavespeeds of first and second kind and damping coefficients in various geologic materials. This solution provides a means of analyzing the influence of material property variations on wavespeed and attenuation. In Part 2 of this work the theoretical solution is incorporated into the numerical code and the code is used in a parametric study on wave propagation velocity and damping.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.226-235
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• 2017

이 논문에서는 워핑 구속조건이 박벽 구조물의 비틀림 거동에 주는 효과를 확인하였다. Vlasov torsion theory를 통해 얻은 이론해 및 EDISON SW의 해석해를 St.Venent torsion theory를 통해 얻은 이론해와 비교하는 방법으로 그 영향을 확인하였다. 이를 통해 Clamped end조건이 단면의 형상 및 단면의 세부 파라미터에 따라 단면의 워핑발생을 제한하여 비틀림거동에 큰 영향을 미칠 수 있음을 확인했다.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.16-25
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• 2004

As underground caverns have many advantages such as safety and operation, they can also be used for gas storage purpose. When liquefied gas is stored underground, the cryogenic temperature of the gas affects the stability of the storage cavern. In order to store the liquefied gas successfully, it is essential to estimate the exact temperature distribution of the rock mass around the caverns. The main purpose of this study is the development of theoretical solution to be able to estimate the temperature distribution around storage caverns and the assessment of the solution. In this study, a theoretical solution and a conceptual model for estimating two and three dimensional temperature distribution around the storage caverns are suggested. Based on the multi-dimensional transient heat transfer theory, the theoretical solution is successfully derived by assuming the caverns shape as simplified geometry. In order to assess the theoretical solution, by performing numerical experiments with this multi-dimensional model, the temperature distribution of the theoretical solution is compared with that of numerical analysis. Furthermore, the effects of the caverns size are investigated.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.137-146
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• 2002

Field piezocone dissipation tests are performed, and the results are compared to the Rowe cell consolidation tests results to investigate the consolidation characteristics of soft marine deposit at the same location in Korea. From these results, statistical formula fur the relation between the coefficients of horizontal consolidation$(c_r)$ from Rowe cell consolidation tests and $t_{50}$ from pore pressure dissipation tests by Piezocone is suggested through the regression analysis. The results are also compared to the existing theoretical formula. It is also shown that suggested formula is similar to Torstensson's(1977) formula based on cylindrical cavity expansion theory and Houlsby and Teh's(1988) formula based on strain path method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.44-52
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• 2016

Kelvin's (1887) theory that predicts position of ship wave crest can be applied only in deep water. Havelock's (1907) theory that predicts cusp locus angle can be applied in whole water depths but cannot predict the position of ship wave crest. In this study, using the linear dispersion fully, we develop the equations to predict ship wave crest in whole water depths and, using the developed equations, we predict cusp locus angle. We simulate ship wave propagation using FLOW-3D in the condition of Johnson's (1985) hydraulic experiment and find that the cusp locus angles predicted by the present theory are close to numerical results of FLOW-3D and hydraulic experimental data. We also simulate for various conditions and compare numerical results of distances between adjacent wave crests and values predicted by the present theory. For Froude number less than unity, the numerical results are close to the values predicted by the theory. For Froude number greater than unity, the constant value of $C_1$ which determines the distance between the ship and the first ship wave crest is almost equal to zero and the numerical results of distances between adjacent ship waves excluding the first ship are close to the values predicted by the theory.

• Transactions of Materials Processing
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• v.1 no.2
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• pp.40-51
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• 1992

냉간단조에 의한 새로운 헬리컬기어 성형공정이 제시되었다. 원형봉재로 부터 헬리컬기어를 압출함에 있어서 압출압력을 계산하기 위하여 상계정리를 적용하여 수치계산하고, 수치해석 결과와 압출하려는 기어의 금형을 설계 제작하여 실험한 결과를 비교 검토하고자 한다. 이론해석상 다이형상으로 인벌류트곡선을 사용한 이론해는 실험결과와 잘 일치하였다. 그리고, 다이의 형상을 평기어부와 헬리컬기어부의 이중구조로 된 신공정이 헬리컬기어부로만 된 사만타공정과 비교해서 금형강도를 향상시킴으로써 다이수명은 증가되었고, 자동차 변속기용으로 헬리컬기어는 KS 기어급수 4~5 급의 정밀도에 해당하는 기어를 가공했다. 이는 사만타공정의 정밀도 보다 향상된 결과를 얻었다.

• 어항어장
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• s.26
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• pp.45-53
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• 1994

본 연구는 유한진폭파 이론(Stokes2, 3, 5차 이론, Streamfunction파 이론)과 미소진폭파 이론(선형파이론)의 각 이론해에 의한 자유수면 변동($\eta$), 물입자수평속도(u), 전파속도(C), 파장(L) 등의 비교 분석을 통하여 각 파랑이론의 적용범위를 검증하고자 했다.

• Journal of the Korean Geotechnical Society
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• v.28 no.11
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• pp.17-31
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• 2012

No analytical solution exists for evaluating in-situ hydraulic conductivity of vertical cutoff walls by analyzing slug test results with consideration of transient flow. There is an analytical solution proposed to interpret a slug test performed in a partially penetrated well within an aquifer. However, this analytical solution cannot be directly applied to the cutoff wall because the solution has been developed exclusively for an infinite aquifer instead of a narrow cutoff wall. To consider the cutoff wall boundary conditions (i.e, constant head boundary and no flux boundary condition), the analytical solution has been modified in this study to take into account the narrow boundaries by introducing the imaginary well theory. Type curves are constructed from the currently derived analytical solution and compared with those of a partially penetrated well within an aquifer. The constant head boundary condition provides faster hydraulic head recovery curve than the aquifer case. On the other hand, no flux boundary condition leads to slower hydraulic head recovery. The bigger the shape factor and deviation of the well and the smaller the width of the vertical cutoff wall are, the more effect of boundary condition was observed. The type curves obtained from the analytical solution for a cutoff wall are similar to those made by the numerical method in the literature.