• 한국지반신소재학회논문집
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• 제19권1호
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• pp.25-33
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• 2020

본 연구에서는 기존 차수재가 수분과의 팽윤성을 갖는 특징을 개선하기 위해 모래, 칼슘-벤토나이트 및 겔화제 혼합물의 트리클로로에틸렌(TCE) 반응에 따른 투수 특성을 평가하였다. 이를 위해 연구 재료의 기본적인 특성 분석, 투수시험을 진행하였다. 투수계수는 칼슘-벤토나이트 혼합 비율이 증가함에 따라 감소하였으며, 겔화제 혼합 비율이 증가함에 따라 증가하였다. 결론적으로, 칼슘-벤토나이트 15%, 겔화제 30% 이상 혼합 시 지하수 유동에서의 투수계수는 α × 10^-4 cm/sec 이상으로 분석되어 지하수 유동을 차단하지 않는 것으로 분석되었다. 또한 TCE 반응 시 혼합차수물의 투수계수는 α × 10^-7 cm/sec 이하로 분석되어, 차단층 투수계수 조건(1.0 × 10^-6 cm/sec 미만)을 만족하였다. 따라서 칼슘-벤토나이트와 겔화제는 TCE로 오염된 토양 및 지하수에 선택적 투수능 변환 특성을 보이는 차수재로서 활용이 가능하다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.201-205
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• 1998

Leakage of hydrocarbon compound from underground storage tank has been a significant issue to the hazard of environmental contaminants. It is therefore necessary to develop the measurement technique of hydrocarbon compound concentration. In this study, the possibility of TDR application to measure concentration of hydrocarbon compound, especially diesel, in a sandy soil was investigated. Experiments were conducted in two different conditions. The first one was to measure the resistances of the soil columns packed according to the various ratios of tab water and diesel content in the total voids. The other was to measure the resistance of the soil under the flow condition where diesel oil was allowed to infiltrate into the KCl-saturated soil column. The experimental results showed that there exists a significant relationship between oil% and TDR-measured resistance. This suggests that TDR can be an effective device to measure the concentration of hydrocarbon compound in a soil.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.493-500
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• 2000

Rock Mass Rating has been widely applied to the underground tunnel excavation and many other practical problems in rock engineering. However, Rock Mass Rating is hard to make out because it is difficult to estimate each valuation items through all kind of field situations and items of RMR have interdependence. So the experts of tunnel assessment have problems with rating rock mass. In this study, using multivariate analysis based on domestic data(1011EA) of water conveyance tunnel, we presented rock mass rating system which is objective and easy to use. The constituents of RMR are decided to RQD, condition of discontinuities, groundwater conditions, orientation of discontinuities, intact rock strength, spacing of discontinuities in important order. In each step, we proposed the best multiple regression model for RMR system. And using data which have been collected at other site, we examined that presented multiple regression model was useful.

• 한국측량학회지
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• 제19권1호
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• pp.67-75
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• 2001

지진 현상은 가장 심각한 인명과 재산의 피해를 초래하는 재해이며, 그 중 액상화 현상은 짧은 시간 안에 큰 피해를 줄 수 있는 재해중의 하나이다. 그 이유는 지반이 순간적으로 현탁액과 같은 상태가 되기 때문에 구조물들이 순간적으로 기울거나 붕괴하는 피해를 유발하게 된다. 이 연구는 춘천지역을 대상으로 지질도, 토양도, 수계망도, 지하수위 자료를 선정ㆍ분류하고, GSIS를 적용하여 경험적인 방법과 내진규정을 기준으로 액상화의 발생 가능지역을 평가하였다.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.41-52
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• 2013

Adequate design of engineered barriers, including canister, buffer and backfill, is important for the safe disposal of high-level radioactive waste. Three-dimensional computer simulations were carried out under different condition to examine the thermal and mechanical behavior of engineered barriers and rock mass. The research looked at five areas of importance, the effect of the swelling pressure, water content of buffer, density of compacted bentonite, emplacement type and the selection of failure criteria. The results highlighted the need to consider tensile stress in the outer shell of a canister due to thermal expansion of the canister and the swelling pressure from the buffer for a more reliable design of an underground repository system. In addition, an adequate failure criterion should be used for the buffer and backfill.

• Archives of Pharmacal Research
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• 제23권4호
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• pp.349-352
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• 2000

A reversed-phase high performance liquid chromatographic method was developed to determine salidroside and tyrosol simultaneously in the Rhodiola rosea. The optimum condition was Nova-pak $C_18$as stationary phase, 6.5% methanol in water as mobile phase and detection at UV 225 nm. The identification was carried out by comparing the retention time and LC/MS spectrum of the relevant peaks with those of isolated standards. The contents of salidroside and tyrosol in the samples gathered from various area in China were ranged over 1.3-11.1 ${m}g/g$ and 0.3-2.2 ${m}g/g$, respectively.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.44-49
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• 2011

The need of data transmission in oceans and other underwater mediums are increasing day by day, so as the research. The underwater medium is very different from that of air. Propagation of electromagnetic wave in water or underground is very difficult because of the conductivity of the propagation materials. In this case, we usually use acoustic signals as ultrasonic but, they are not easy to transfer long distance with coherent method because of time varying multipaths, Doppler effects and attenuations. So, we use non-coherent methods such as FSK or ASK to communicate between long distances. But, as the propagation speed of acoustic wave is very slow, BW of the channel is narrow. It is very hard to guaranty the enough speed for the transmission of digital image data. In previous studies, we proposed this data communication protocol theoretically. In this paper, an underwater channel is modeled and this protocol is tested in this channel condition. The results show that the protocol is 4-6 times faster than ASK. Some relations and results are shown depending on the data length, channel length, bit rate etc.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.731-736
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• 2006

Groundwater heat pump (GWHP) system has been expected to achieve the higher coefficient of performance (COP) and more energy-saving than the conventional air-source heat pump (ASHP) system. Its performance significantly depends on the characteristics of groundwater and the underground thermal properties. Furthermore, there is a large difference of COP in utilizing groundwater between as a heat resource and as a thermal storage medium. For properties of groundwater there is suitable utilizing system. However, many of GWHP systems have not been considered sufficiently such properties. This research describes optimization of GWHP system according to the properties of groundwater based on 3D numerical heat and water transport simulation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.329-332
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• 1999

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as underground box structure, mat-slab of nuclear reactor buildings, dams or large footings, foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, pre-cooling which lowers the initial temperature of fresh concrete with ice flake, pipe cooling which cools the temperature of concrete with flowing water, design change which considers steel bar reinforcement, operation control and so on. The objective of this paper is largely two folded. Firstly we introduce the cracks control technique by employing low-heat cement mix and thermal stress analysis. Secondly it show the application condition of the cracks control technique like sidewall of LNG in Inchonl.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.842-847
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• 2008

Despite of the increasing number of the application of the drilled shaft pile in construction site, most of the study of pile capacity has been centered side shear resistance. But it is common that the drilled shaft is socketed on the rock so as to use the bearing resistance, so prediction of the toe's movement and characteristic of the bearing capacity is important as the side shear resistance. Therefore the model tests were performed in order to study the characteristic of bearing capacity on rock mass. The material of the test blocks were the mortar which was mixed with sand, cement and water, and test block size was $240{\times}240{\times}240mm$. Load was pressed by the 45mm of diameter of miniaturized pile and plate jack and steal plate were used to the confined stress for representing the underground condition. The relation of load-displacement was measured in many different conditions of rock mass such as direction of discontinuities, spacing and strength, and q-w curves of the toe of the pile were verified in each condition.