• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.188-191
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• 2003

Sing]e-well-push-pull tests were developed for use in assessing the feasibility of in-situ aerobic cometabolism of chlorinated aliphatic hydrocarbons (CAHs). The series includes Transport tests, Biostimulation tests, and Activity tests. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide or chloride (conservative tracers), propane (growth substrate), ethylene, propylene (CAH surrogates), dissolved oxygen (electron acceptor) and nitrate (a minor nutrient). Tests were conducted at an experimental well field of Oregon State University. At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the dissolved gases and nitrate prior to biostimulation. Biostimulation tests were conducted to stimulate propane-utilizing activity of indigenous microorganisms and consisted of sequential injections of site groundwater containing dissolved propane and oxygen. Biostimulation was detected by the increase in rates of propane and oxygen utilization after each injection. Activity tests were conducted to quantify rates of substrate utilization and to confirm that CAH-transforming activity had been stimulated. In particular, the transformation of injected CAH surrogates ethylene and propylene to the cometabolic byproducts ethylene oxide and propylene oxide provided evidence that activity of the monooxygenase enzyme system, responsible for aerobic cometabolic transformations of CAHs had been stimulated. Estimated zero-order transformation rates decreased in the order propane > ethylene > propylene. The series of push-pu3l tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ aerobic cometabolism of CAHs.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.193-206
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• 2018

In this study, as part of the "Small-scale $CO_2$ Injection-Demonstration Project in Offshore Pohang Basin", we performed drilling and completion of a $CO_2$ injection well from the offshore platform installed in the Yeongil Bay, Pohang city, Gyeongsang buk-do. The drilling of injection well was carried out from an offshore platform installing on the sediment formations of the Pohang Basin. Drilling diameters were reduced by stages, depending on the formation pressure and groundwater pressure along a depth and the casing installation and cement grouting in drilled hole were performed at each stage. The injection well was drilled to a final depth of 816.5 m with a hole diameter of 4 7/8 inches (${\Phi}124mm$) and the perforated casing for an injection section was installed in a depth of 746.5~816.5 m. Injection tubing, packer, and christmas tree were installed for the completion of an injection well for $CO_2$. The validation project of the $CO_2$ injection was accomplished successfully by drilling the injection well and installing the injection facilities, and through the suitable $CO_2$ injection process. The current injection facility is a facility for small-scale injection demonstration of 100 tons. In the case of large-scale demonstration facility test of a capacity of 10,000 tons, research is underway through the upgrading of the injection facilities.

• Journal of the Korea Institute of Building Construction
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• v.19 no.5
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• pp.411-419
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• 2019

Underground concrete structures are constructed under a geographical environment called underground and exposed to various environments that promote deterioration. Among them, groundwater promotes deterioration of underground concrete structures due to contaminated water from the ground. In this study, the chemical resistance performance test evaluation of five different receptors for a total of 15-type leakage repair materials of five series was conducted to determine the chemical stability of the leakage repair material used in the crack area. The results show a general increase and decrease in most chemical receptors, but the biggest increase and decrease was shown in acrylic systems, which were found in sodium chloride and sodium hydroxide, and epoxy was found in hydrochloric acid. The cement system is showing a lot of increase and decrease in sodium chloride. It is expected that the results of these studies will be used as a basis for chemical stabilization in the development of new materials.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.15-23
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• 2023

The grouting method is a method of construction for the purpose of waterproofing and reinforcing soft ground. When grout is injected into the ground, there are various types of penetration and diffusion of grout depending on the shape of the ground, the size of soil, the porosity, and the presence or absence of groundwater. the current situation. Therefore, in this study, to investigate the penetration performance of the grouting to conductive material, laboratory tests were performed on the addition of the conductive material. In the injection test, 0%, 3%, and 5% of the mixed water were added as conductive materials to the grout, and the original ground condition was composed of various types of ground composed of gravel and silica sand. Conductive grout is injected by pressure into the model ground using a dedicated injection device, and the injection time (t), pressure (p), flow rate (v) and injection amount (q) are measured, and the hardened body injected in the model ground is collected. Penetration performance was evaluated. In the results of the grout injection experiment, the amount of conductive material used and the grout injection rate showed an inverse relationship, and it was confirmed that the penetration pattern was changed according to the size of the soil particles in the model ground. The grout containing the conductive material has relatively good penetration into the ground and excellent strength and durability of the hardened body, so it was judged that it could be used as an additive for measuring the penetration range of the grout.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.1
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• pp.24-31
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• 2000

Soil air permeability and influence of radius in air injection/extraction tests were estimated. These are important factors in the determination of optimal design for SVE or bioventing system. For evaluation of the effects of air leakage from the ground surface on those factors, Theis (1935) and Hantush (1960) methods were used in the data analysis. The air permeability of the studied area was in the range of 1.64$\times$$10^{-7}$~5.66$\times$$10^{-6}$ $\textrm{cm}^2$, and this result would be used for the design of SVE or bioventing system.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.317-320
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• 2004

정압주입시험(Constant Head Injection Test, CHIT)은 결정질 암반의 구간별 수리전도도 및 투수계수를 구하는 전통적인 수리시험방법이다. 본 연구에서는 Visual Modflow 수치코드를 사용하여 정압주입시험에 대한 부정류 모의를 수행하였다. 수치모의 결과 주입공에서 매질로 시간별 주입되는 유량은 30분이 경과한 후부터 거의 일정하게 유지되는 양상을 확인할 수 있는데, 현장에서 정압주입시험을 할 때 적어도 30분 이상의 시첩을 실시해야 함을 알 수 있었다. 시험구간에 따른 수리전도도 값은 시험구간의 크기에 상관없이 거의 일정한 값을 보이고 있어, 시험구간의 크기는 정압주입시험에서 크게 유의하지 않아도 된다고 판단된다. 그러나, 시험구간별 주입 압력에 따른 수리전도도 값의 변화를 살펴본 결과, 시험 구간의 크기와 주입 압력 값이 클수록 산출되는 수리전도도 값이 매질의 수리전도도 값과 차이가 나는데, 현장조사에서 시험구간과 주입 압력 값에 대한 고려가 있어야 함을 지시한다. 매질의 수직적 이방성에 따른 모의결과 $K_{zz}$ / $K_{xx}$ and $K_{yy}$ 값이 작아질수록 수리전도도 값이 작아지는데, 현장조사 결과를 해석함에 있어 매질의 수직적 이방성은 주의를 기울여야 한다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.168-171
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• 2003

연속주입추적자시험이 실시된 현장사이트의 규모는 4.5m$\times$4.5m$\times$6.0m 정도이다. 시험 사이트내에서 실시된 추적자시험은 주입공(Pl)에서 Rhodamine WT 50ppm 용액을 1.8$\ell$/min의 주입율로 6일 동안 연속적으로 주입함과 동시에 관측공(P2, P3, Il, I2, I3)에서 일정한 시간간격으로 지하수를 채수하여 추적자농도를 산출하였다. 시험결과, 지하수면 하부를 포함하는 관측공(P2, P3)의 최대추적자농도는 초기주입농도의 10% 정도이며, 지하수면 상부에 위치한 지하수공(Il, I2, I3)들에서의 최대추적자농도는 초기농도의 75% 정도로서 추적자의 농도차이가 상대적으로 매우 크게 나타났다. 본 연구에서는 자유면대수층내에서 포화대를 포함한 관측공과 비포화대만을 포함한 관측공에서의 수리분산특성에 대해 비교.분석한 결과, 오염물이 연속적으로 토양에 유입되는 경우 비포화대 구간에서는 이류기작에 의한 농도희석이 거의 없으므로 오염물농도가 매우 클 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.189-200
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• 1991

The purpose of this study is to examine the cut-off effect in aquifer by chemical grouting. Moreover, injection tests using specially prepared injection equipment of 1.5 shot system which hydrauric condition can be controlled are attempted to investigate the cut-off effect by confirming the gelling condition of samples according to the variation of flow velosity. And the permeability is measured according to changing of time by falling head test in order to consider the durability of grouts. Therefore to increase the cut-off effect in groundwater flow, shortening the gel-time according to the increasement of flow velocity, increasing the concentration and quantity of grouts(grouting ratio) according to the increasement of that, and as another direct method, contracting the distance between grouting holes or enlarging the grouting line should be done. These coefficients should be designed by data based on injection test in laboratory and field.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.414-423
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• 2006

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925, Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower and the motion of grout is also a function of formation permeability. Viscosity of grout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this thesis, characteristics of new cement grout material that is developed recently is studied: injectable volume of new grout material is tested in two different sizes of sands, and the method to calculate injectable volume of grout is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to be an exponential function of time. And lumped parameter $\theta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressure.

• Geosciences Journal
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• v.22 no.6
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• pp.1041-1052
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• 2018

A single-well push-drift-pull tracer test using two different tracers ($SF_6$ and salt) was performed at the Environmental Impact Test (EIT) site to determine suitable locations for monitoring wells and arrange them prior to artificial $CO_2$ injection and leak tests. Local-scale estimates of hydraulic properties (linear groundwater velocity and effective porosity) were obtained at the study site by the tracer test with two tracers. The mass recovery percentage of the volatile tracer ($SF_6$) was lower than that of the non-volatile tracer (salt) and increased drift time may make degassing of $SF_6$ intensified. The $CO_2$ leakage monitoring results for both unsaturated and saturated zones suggest that the $CO_2$ monitoring points should be located near points at which a high concentration gradient is expected. Based on the estimated hydraulic properties and tracer mass recovery rates, an optimal $CO_2$ monitoring network including boreholes for monitoring the unsaturated zone was constructed at the study site.