• 자원환경지질
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• 제25권3호
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• pp.225-232
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• 1992

The hydrothermal alteration is evaluated using multicomponent equilibrium calculations with the program CHILLER for the reactions between hydrothermal water and rhyolite at the temperature of $300^{\circ}C$ and pressure of 500 bars. The chemical-reaction model on the depositional processes of the sericitite confirms that the hydrothermal water-rock interaction(hydrothermal alteration) is the main mechanism of the sericitite formation. The principal change in the aqueous phase during the reaction is the pH increase. Overall trends for the major species are the increase in total molalities of K, Ca, $SiO_2$, Al, Mg, Fe, Na, and sulfide in solid phase with hydrothermal water-rhyolite reaction and the decrease of them in aqeous solution by precipitation of hydrothermal products. Quartz and sericite are the first minerals to form. The sequence of minerals to precipitate following them is chlorite, epidote, pyrite and microcline as water/rock ratio decreases. Although calculated results cannot duplicate the complexities of natural hydrothermal alteration, the calculation provides thermodynamic constraints on the natural process. The calculation results resemble those of experimental studies. Sericitite forms where pH decreases and water/rock ratio increases.

• 터널과지하공간
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• 제8권3호
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• pp.184-193
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• 1998

방사성 폐기물의 안전한 처분을 위해서는 암반의 역학적, 열적, 유체 거동 뿐 아니라 암반과 물 사이의 물리 화학적 상호작용을 이해할 필요가 있다. 또한 지질구조, 지하현지응력, 습곡, 열수작용, 마그마의 관입, 판구조 등과 같은 많은 조건을 모델링하고 예측하기 위해서는 암석의 역학적, 수리적 특성을 알아야 한다. 이 연구는 심부 암반에 폐기물 처분과 관련된 암석역학적인 사항들에 대해 연구들에 기초하고 있다. 이 논문은 변하는 온도 상태에서 암반의 역학적 수리적 거동, 암반의 열-수리-역학적 상호작용 해석과 불연속 암석의 거동 특성 등을 포함한다. 역학적 특성은 Interaken 암석역학 시험 시스템으로 측정되었으며, 수리적 특성에는 순간 증압 투수계수 측정 시스템이 사용되었다. 모든 결과에서 암석 특성은 온도 변화에 민감함을 보였다.

• 자원환경지질
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• 제31권2호
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• pp.101-110
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• 1998

The purpose of this study is to elucidate the source of U anormaly formed in stream water of the drainage system around the Shinbo talc mine area based on the hydrochemical properties of water masses including surface water and groundwater. The hydrochemical properties of water masses in the Shinbo talc mine area are divide into three types; Type I : $Ca(Mg)SO_4$ type with high U content as shown in the stream water flowout from the mine, Type II : $Ca(HCO_3)_2$ type with high U content as in deep groundwater, Type III : $Ca(HCO_3)_2$, type with low U content as in the other stream water and shallow groundwater. It is necessary to emphasize that in deducing the uranium source, a distinct discrimination between type I and type II is showed in their hydrothermal properties in spite of commonly having a high uranium content, which in turn means the occurrence of a different water-rock interaction processes between both type. All evidences suggest that type II groundwater have acted as a primary media in the transport of uranium and that, as the groundwater flows through the talc mineralization zone, water composition of type II was transformed into that of type I water as the results of a secondary water rock interaction process, caused by imposition of new mineralogically controlled thermodynamic constraints. Consequently, in the viewpoint of hydrochemical exploration, the investigation of the hydrologic circulation system and the hydrogeologic properties for the aquifer of type II groundwater shall be done first of all and will provide a crucial clue on tracing the uranium mineralization zone occurred in the Shinbo talc mine area.

• 터널과지하공간
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• 제18권6호
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• pp.465-479
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• 2008

저심도 터널 굴착시 예상되는 암반 거동을 정량적으로 파악하기 위해 계층 분석적 의사결정 방법과 암반 공학 시스템 방법을 적용하여 암반 거동 지수를 산정하였다. 복잡하고 조직화되지 않은 암반 거동을 효과적으로 결정하기 위해 쌍대 비교 매트릭스를 이용하는 계층 분석적 의사결정 방법과 상호 영향 매트릭스를 이용하는 암반 공학 시스템 방법을 적용하였고, 전문가 의견의 불확실성을 극복하고자 퍼지 델파이 방법을 적용하였다. 저심도 암반 터널 굴착 시 예상되는 암반 거동 유형으로 소성 변형, 낙반과 낙석을 제시하였다. 각각의 암반 거동 유형을 결정하기 위해 일축압축강도, 암질 지수와 절리 조건을 포함하는 암반 내생적 매개변수, 응력, 지하수와 지진 조건을 포함하는 암반 외생적 매개변수와 굴착 매개변수를 고하였다. 이를 서울 지하철 O호선 O공구 설계에 적용하여 예상되는 암반 거동 유형을 정량적인 암반 거동 지수로 제시하였다.

• 지구물리
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• 제9권2호
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• pp.129-134
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• 2006

Recently, spillways are need to control stable water level for supporting main dams because of floods by unusual change of weather such as Typhoon Rusa. This study has been focused on the amount of leakage through the rock mass distributed fractures and joints under the opened emergency spillway. It is very important to evaluate the amount of leakage as these affect stability of spillway by interaction between effective stress and pore pressure. The commercial program MAFIC has been used for analyzing groundwater flow in fractured rock mass. The results showed that the values of range, average and deviation of leakage were 2.85∼3.79×10-1, 3.32×10-1 and 1.70×10-2 m3/day/m2 respectively. Secondary, we have estimated the effect of grouting after the transmissivity(Tf) of joint 1 as main pathway of leakage known from above results was changed from 1.78×10-7 to 1.59×10-9 m2/s. The results showed that the values of range, average and deviation of leakage were 7.80×10-4∼1.53×10-3, 1.18×10-3 and 1.32×10-4 m3/day/m2 respectively. As the result, the amount of leakage after grouting has been decreased by a ratio of 1 to 277.

• 한국환경과학회지
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• 제25권11호
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• pp.1563-1573
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• 2016

The aim of this study was to evaluate the occurrence of vanadium in Jeju Island groundwater, focusing on the spatio-temporal patterns and geochemical controlling factors of vanadium. For this, we collected two sets of groundwater data: 1) concentrations of major constituents of 2,595 groundwater samples between 2008 and 2014 and 2) 258 groundwater samples between December 2006 and June 2008. The concentrations of groundwater vanadium were in the range of $0.2{\sim}71.0{\mu}g/L$ (average, $12.0{\mu}g/L$) and showed local enrichments without temporal/seasonal variation. This indicated that vanadium distribution was controlled by 1) the geochemical/mineralogical composition and dissolution processes of original materials (i.e., volcanic rock) and 2) the flow and chemical properties of groundwater. Vanadium concentration was significantly positively correlated with that of major ions ($Cl^-$, $Na^+$, and $K^+$) and trace metals (As, Cr, and Al), and with pH, but was negatively correlated with $NO_3-N$ concentration. The high concentrations of vanadium (>$15{\mu}g/L$) occurred in typically alkaline groundwater with high pH (${\geq}8.0$), indicating that a higher degree of water-rock interaction resulted in vanadium enrichment. Thus, higher concentrations of vanadium occurred in groundwater of $Na-Ca-HCO_3$, $Na-Mg-HCO_3$ and $Na-HCO_3$ types and were remarkably lower in groundwater of $Na-Ca-NO_3$(Cl) type that represented the influences from anthropogenic pollution.

• Structural Engineering and Mechanics
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• 제71권6호
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• pp.699-712
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• 2019

The reinforced concrete lining of hydraulic pressure tunnels tends to crack under high inner water pressure (IWP), which results in the inner water exosmosis along cracks and involves typical hydro-mechanical interaction. This study aims at the development, validation and application of an indirect-coupled method to simulate the lining cracking process. Based on the concrete damage plasticity (CDP) model, the utility routine GETVRM and the user subroutine USDFLD in the finite element code ABAQUS is employed to calculate and adjust the secondary hydraulic conductivity according to the material damage and the plastic volume strain. The friction-contact method (FCM) is introduced to track the lining-rock interface behavior. Compared with the traditional node-shared method (NSM) model, the FCM model is more feasible to simulate the lining cracking process. The number of cracks and the reinforcement stress can be significantly reduced, which matches well with the observed results in engineering practices. Moreover, the damage evolution of reinforced concrete lining can be effectively slowed down. This numerical method provides an insight into the cracking process of reinforced concrete lining in hydraulic pressure tunnels.

• 자원환경지질
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• 제33권6호
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• pp.469-489
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• 2000

The hydrogeochemical and isotopic studies on deep groundwater (below a 550 m depth from the ground surface) in the Munkyeong area, Kyeongbuk province were carried out. Two types of deep groundwater (${CO_2}$-rich groundwater and alkali groundwater) occur together in the Munkywong area. ${CO_2}$-rich groundwater (Ca-${HCO_3}$ type) is characterized by low pH (5.8~6.5) and high TDS (up to 2,682 mg/L.), while alkali groundwater (Na-${HCO_3}$ type) shows a high pH (9.1~10.4) and relatively low TDS (72~116 mg/L). ${CO_2}$-rich water may have evolved by ${CO_2}$ added at depth during groundwater circulation. This process leads to the dissolution of surrounding rocks and Ca, Na, Mg, K and ${HCO_3}$ concentrations are eniched. The low $Pco_2$ ($10^{-6.4}$atm) of alkali groundwaters seems to result from the dissolution of silicate minerals without a supply of ${CO_2}$. The ${\delta}^{18}O$ and ${\delta}^D$values and tritium data indicate that two types of deep groundwater were both derived from pre-thermonuclear meteoric water and have evolved through prolonged water-rock interaction. The carbon isotope data show that dissolved carbon in the ${CO_2}$-rich water was possibly derived from deep-seated ${CO_2}$ gas, although further studies are needed. The ${\delta}^{34}S$ values of dissolved sulfate show that sulfate reduction occurred at great depths. The application of various chemical geothermometers on ${CO_2}$-rich groundwater shows that the calculated deep reservoir temperature is about 130~$l75^{\circ}C$. Based on the geological setting, water chemistry and environmental isotope data, each of the two types of deep groundwater represent distinct hydrologic and hydrogeochemical evolution at depth and their movement is controlled by the local fracture system.

• 자원환경지질
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• 제31권6호
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• pp.485-498
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• 1998

The water-rock interaction and anthropogenic contamination affecting to geochemical composition of shallow and deep groundwaters were investigated in the agricultural area of Myunggok-ri, Kongju. The shallow groundwater is classified into the chemical types of $Ca-HCO_3$ and $Ca-Cl(SO_4)$ and shows weak acid having an average pH 6.2. Deep groundwater shows the uncontaminated composition of the chemical types of $Na-HCO_3$ and Na $(Ca)-HCO_3$ with pH of 8.4~8.8. The grouping approach of chemical data of waters shows the distinguished trend between water composition influenced anthrophogenic input and water composition mainly determined by natural process such as water-rock interaction. The main anthropogenic inputs affecting chemical composition of shallow groundwater are the contaminants such as $K^+$, $NO_3{^-}$, $Cl^-$ having average values of 4.4 mg/l, 22 mg/l, 13.7 mg/l, respectively. The contaminants were probably derived from fertilizer, sweage, septic tank, and stable, etc. The hydrogen and oxygen isotopic compositions indicate that five deep groundwaters were recharged from different altitudes, and that shallow and deep groundwaters were originated from meteoric water. Tritium contents of waters suggest that deep groundwater was recharged before or just after 1950s, and that shallow groundwater is much younger than deep groundwater. The results of this study may serve as a basic data for the future study of shallow groundwater as a drinking water in agricultural area, in Korea.

• 자원환경지질
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• 제55권5호
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• pp.465-475
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• 2022

해저열수광상(seafloor massive sulfide deposit, SMS)은 다량의 유용금속을 포함하는 중요한 광물 자원으로서 그 성인적 특성 및 금속 함량 변화는 주로 모암과 마그마로부터 금속과 황을 공급하는 물-암석 상호작용과 마그마성 휘발 성분의 용리에 의해 결정된다. 이러한 금속 공급원들은 지구조환경에 따라 다양한 특성을 보이기 때문에 해저열수광화작용에 대한 이들의 기여는 여전히 불분명하다. 본 논평에서는 중앙해령 및 화산호 지역 SMS 광상의 광물·지구화학적 특성을 검토하여 서로 다른 금속 공급원의 영향을 파악하고 향후 진행되어야 할 성인 연구의 방향성에 대해 논하고자 한다. 연구 결과 황비동석 및 큐바나이트, 방연석, 중정석의 산출은 각각 마그마 영향과 물-암석 상호작용의 기여를 반영하여 금속 공급원 특성 차이에 의한 해저열수광상의 유형 구분을 가능케 한다. 또한, 황철석의 Co, As, Hg 거동 특성 및 섬아연석의 철 함량 변화는 지구조환경에 따른 금속 공급원의 영향을 반영하는 효율적인 경험적 지표가 될 수 있다. 현재까지 연구는 주로 열수 침전에 의한 광체에만 국한되었기 때문에 해저열수광상의 성인적 특성을 포괄적으로 이해하기 위해서는 마그마 기원 황화광물과 황산염광물을 대상으로 한 추가 연구가 필수적이다.