• 한국지반공학회지:지반
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• 제14권4호
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• pp.47-60
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• 1998

본 연구에서는 남해안 해성점토의 일정변형률 압밀특성을 파악하기 위해 표준압밀시첩과 변형률 속도가 다른 일정변형율 압밀시험을 수행하고 이들 결과를 비교.분석하였다. 표준압밀시험 및 일정변형율 시험에서 선행압밀하중을 산정하기 위하여 여러 제안된 방법을 사용하였으며 각 방법의 적용성을 검토하였다. 또한, 변형률 속도가 응력-변형뮬 관계, 간극수압, 그리고 선행압밀 하중에 미치는 영향을 분석하였다. 해석결과에 의하면 압밀곡선의 분포와 선행압밀하중비($a_2=\sigma'_{pCRS}/\sigma'_{pConv}$)는 변형률 속도의 영향을 받지만, 정규압 밀구간의 압축지수는 상대적으로 변형률 속도의 크기와 무관한 것으로 나타났다. 해성점토의 선행압밀하중비는 변형률 속도의 대수축척에 비례하여 증가하는 것으로의 변형률 속도에서 평균적으로 1.11~1.30의 분포를 보였다. 일정변형률 압밀시험에서 간극수압비는 변형플 속도가$6.67\times10^{-4}$ %sec일 때를 제외하고는 6.0%를 초과하지 않는 것으로 나타났다. 정규압밀구간의 압축지수, 압밀계수와 투수계수는 각각 0.59~0.95, $0.56\times10^{-3}~3.0\times10^{-3} cm^2/sec,\; 그리고 \;2.0\times10^4~7.0\times10^{-4} cm/sec$의 분포를 보였다.

• 방사성폐기물학회지
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• 제10권1호
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• pp.1-11
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• 2012

Rorabaugh(1953)에 의해 재정리된 단계양수시험 해석해 $s_w=BQ+CQ^p$는 단열암반대수층에서 비선형으로 증가하는 수위강하에 매우 적합하며, 현장에서 관측된 수위강하 값과 추정된 수위강하 사이의 제곱근 평균제곱오차(RMSE) 값이 매우 낮음을 보여주었다. 우물수두손실($CQ^p$)의 $C$ 값은 $3.689{\times}10^{-19}{\sim}5.825{\times}10^{-7}$, $P$ 값은 3.459~8.290의 범위로 산정되었으며, 지표로부터 하부심도로 내려 갈수록 양수율 증가에 따른 수위강하는 매우 크게 나타났다. 단열암반대수층에서의 우물수두손실은 다공질매질에서와 달리 단열특성(단열의 틈, 간격, 상호 연결성)에 의한 영향으로 나타나므로, 우물수두손실의 $C$ 와 $P$ 값은 단열암 반대수층의 난류구간과 고 저 투수성 단열암반의 특성을 해석하는데 매우 중요하다. 그 결과, 우물수두손실 항의 $C$ 와 $P$ 값에 대한 회귀분석 결과로부터 암반대수층의 난류구간과 수리특성의 관계가 파악되었으며, $C$ 와 $P$ 값의 관계가 단열암반대수층의 수리특성 해석에 있어 매우 유용함을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제17권4호
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• pp.367-374
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• 2019

This study concluded the results of a research on the features of cement based permeation grout, based on some important grout parameters, such as the rheological properties (yield stress and viscosity), coefficient of permeability to grout ($k_G$) and the inject ability of cement grout (N and $N_c$ assessment), which govern the performance of cement based permeation grouting in porous media. Due to the limited knowledge of these important grout parameters and other influencing factors (filtration pressure, rate and time of injection and the grout volume) used in the field work, the application of cement based permeation grouting is still largely a trial and error process in the current practice, especially in the local construction industry. It is seen possible to use simple formulas in order to select the injection parameters and to evaluate their inter-relationship, as well as to optimize injection spacing and times with respect to injection source dimensions and in-situ permeability. The validity of spherical and cylindrical flow model was not verified by any past research works covered in the literature review. Therefore, a theoretical investigation including grout flow models and significant grout parameters for the design of permeation grouting was conducted in this study. This two grout flow models were applied for three grout mixes prepared for w/c=0.75, w/c=1.00 and w/c=1.25 in this study. The relations between injection times, radius, pump pressure and flow rate for both flow models were investigated and the results were presented. Furthermore, in order to investigate these two flow model, some rheological properties of the grout mixes, particle size distribution of the cement used in this study and some geotechnical properties of the sand used in this work were defined and presented.

• 설비공학논문집
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• 제5권4호
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• pp.243-248
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• 1993

In this research, unsteady groundwater flow in unconfined and homogeneous three layer aquifers is studied theoretically and experimentally. Numerical solutions are obtained by Runge Kutta and Runge Kutta Gill method after transforming the governing nonlinear partial differential equations to nonlinear ordinary differential equations. Experimental apparatus includes a test section filled with fine, medium and coarse sands. Experimental results are compared with the numerical solutions and both experimental and numerical results correspond well with each other. This numerical approach may be also applied to the cases which have more aquifers.

• 한국농공학회논문집
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• 제57권3호
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• pp.87-92
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• 2015

Cultivation on reclaimed tidal land is often difficult in the problem such as high salinity of soil, bad drainage because of high level of groundwater. Many researches have been made efforts to solve these problems, but effect of improvement is low and practicality is insufficient. In this study, through numerical analysis of the transport properties of salt and water, we suggested underground drainage of the reclaimed land and the desalination promotion methods in the soil. The results of characteristic of desalination and seepage analysis of underdrain show that underdrain is able to increase twice of the underground seepage amount when installing perforated pipe with horizontal filter (width 50cm) more than installing only the perforated pipe. For soil which coefficient of permeability is below $1{\times}10^{-4}cm/s$ that desalination with pond water is not possible, a method to increase the permeability of the soil is necessary. Therefore, it was concluded that application of underdrain using perforated pipe with horizontal filter would be low-cost and practical.

• 한국농공학회지
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• 제31권3호
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• pp.70-80
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• 1989

In this research program special triaxial compression tests and dehydration-swelling tests under the condition of freeze-thaw process were conducted to show the effects of freezethaw process on the physical properties of weathered granite soil, and their results as follows; 1.Consolidation settlement of weathered granite soil mass was increased due to freeze-thaw process, and the initial tangent coefficient of dense state was higher than that of loose state. 2.Compression behaviour of soil was increased according to the decrease of freezing temperature, and when the freezing temperature was reached under - 10$^{\circ}$C, the compression rate was not influenced by change of freezing temperature. 3.The experiments showed that the void ratio and permeability of soil were converged into their values of shrinkage limit, and the permeability was higher due to the freeze-thaw process and as the lower the freezing temperature. 4.The decrease of liquid limit was indicated as the lower the freezing temperature, and as more the freeze4haw cycles, the moisture content was shown the lower side. 5.It was shown that the shrinkage was decreased by freeze-thaw process and not influenced by way of freezing temperature, but dehydration rate was higher.

• 한국지반신소재학회논문집
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• 제10권1호
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• pp.37-42
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• 2011

본 연구에서는 아스팔트순환골재를 이용한 투수성 콘크리트의 역학적 특성을 알아보기 위하여 투수성 콘크리트의 단위시멘트량, 잔골재 비율, 물시멘트(w/c)비의 혼합율 변화에 따른 역학적 특성과 구조체로서 요구되는 소요강도에 대하여 분석하고자 하였다. 순환골재의 사용성을 높이기 위하여 입도조정 없이 13mm 아스팔트순환골재를 사용하였으며, 물시멘트비는 빈배합이 되도록 결정하였다. 분석결과 압축강도는 18.2~19.5Mpa을 보였으며 투수계수는 평균적으로 8.0E-02cm/sec 값을 나타내었다.

• 한국안전학회지
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• 제27권6호
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• pp.109-114
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• 2012

This study is the things to experiment and evaluate the performance of self-healing water-proofing on the concrete to be using the crystal growth composite waterproofing admixture. The cylinder to be making on the concrete by ${\varnothing}150{\times}300$ mm for evaluating the performance of self-healing water-proofing was aging 90 days and cut on a 50 mm. So, it prompted the crack and applied. After it measured the quantity of water to be flow the water throughout the crack part of the cylinder, it applied the basic formular of Darcy's law and calculated the coefficient of water permeability. So, it verified the performance of self-healing water-proofing on the basis of the changing shape of the water permeability. This experiment is the thing to be applied the general evaluation of the structure to demand the real watertightness on doing for the evaluating of performance of the quantity of water leak and self-healing water-proofing about the various penetration crack.

• Bulletin of the Korean Chemical Society
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• 제3권1호
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• pp.23-30
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• 1982

For the study of transport phenomena of an aqueous NaCl solution through a cuprophane membrane, a new apparatus was constructed. The volumc flow rate Q, the permeability coefficient U, and the permeability constant K were measured or determined by using this apparatus. The experimental temperature range was 5 to $35^{\circ}C$, and the applied pressure increments were 10 to 40 psi. By assuming that the cuprophane membrane is composed of n parallel cylindrical capillaries of circular cross-section and that the flow of the solution through the capillaries follows the Poiseulle law, the mean radius r of the capillaries and the number n of the latter in the membrane were evaluated. By using a reasonable assumption concerning the radius ${\eta}'$ of the species diffusing through the membrane, it was concluded that the contribution of the diffusive flow to the total flow rate Q is less than 10%. Thus, the Q was treated as the rate due to the viscous flow, and the viscosity ${\eta}_m$ of the solution in the membrane phase was evaluted, and it was found that ηm is nearly equal to ${\eta}_b$, the bulk viscosity of the solution. From this fact, it was concluded that in the capillaries, no change occurs in the physical state of the NaCl solution. The value of ( = 4.27 kcal/mole) and ${\Delta}Sm^{\neq}$(4.28 eu) were obtained for the viscous flow. A possible explanation was given.

• 한국지반공학회논문집
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• 제26권1호
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• pp.21-33
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• 2010

본 논문에서는 송도지반의 압밀 및 투수특성을 현장 및 실내시험을 이용하여 평가하였다. 송도지반의 압밀층은 약 E.L-15m 상부에 분포하는 실트질 점토층이며, 압밀층 사이에 배수층 역할을 할 것으로 판단되는 모래층이 분포하는 것으로 분석되었다. 압밀층 상부는 매립 전에는 과압밀 상태였으나 매립 후에는 정규압밀 또는 약간 과압밀된 상태로 전이된 것으로 분석되었다. 압밀 및 투수특성은 점토, 실트질 점토, 점토질 실트 등의 흙의 종류에 따라서 큰 차이를 보이는 것으로 나타났으며, 본 논문에서는 각 지층에 대한 압밀 및 투수특성 값의 평균 및 범위, 이방성 분석결과를 제시하였다. 본 논문의 압밀 및 투수특성에 관한 연구결과는 송도지역의 초기 지반설계자료로 사용될 수 있을 것으로 판단된다.