• 자원환경지질
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• 제36권5호
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• pp.339-347
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• 2003

울산광역시에 대한 해수침입 가능성을 171개 지하수 수질분석 자료를 이용하여 연구하였다. 연구지역에서 Cl의 함량이 높은 지역은 남구의 태화강 주변 저지대로서 최대 11,300 mg/L이고, 동구 해안일대는 지질학적 특성 때문에 상당히 낮은 Cl 함량을 보인다. Cl의 함량이 낮을수록 해수의 Br:Cl 함량비인 $34.7{\times}10^{-4}$에서 크게 벗어나지만, Cl의 함량이 100 mg/L 이상인 지하수는 해수의 Br:Cl 비인 $34.7{\times}10^{-4}$에 근접함을 보인다. 171개 지하수 중 Cl의 함량이 500 mg/L이상 되는 11개 시료의 Cl, Br, K, Na의 조성비는 해수와 비슷하나, Ca, Mg, $SO_4$, $HCO_3$, $SiO_2$의 조성비는 해수와 다르다. Cl함량이 500 mg/L 이상인 11개 지하수 시료의 Na/Cl 몰비는 0.35∼2.08의 범위이며(해수 0.75), Ca/Cl 몰비는 0.001∼0.20의 범위(해수 0.02), Mg/Cl 농도비는 0.001∼0.22의 범위(해수 0.09)를 보인다. 따라서 현재 태화강 일대 지하수의 Cl 함량이 높은 것은 해수침입보다는 과거 도시화 이전 충적층에 축적되어 있었던 염분이 고립되어 나타나는 현상으로 추정되며, 이 염분의 농도는 지하수 유출량보다는 유입량이 더 많은 도시지역 지하수 시스템을 고려할 때 시간이 지남에 따라서 점점 낮아질 것으로 예상된다.

• 한국환경과학회지
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• 제7권4호
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• pp.461-466
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• 1998

One hundred and thirty two ground water samples from the Usan area were divided into urban and non-urban groupings and were assessed between 1993 and 1996. The results of statistical analysis were as follows: There were significant differences between the two groupings in the average value of the following water quality parameters: total hardness, nitrate , pH, iron, ammonia and chloride ion in the order of Z-score . Because total hardness, nitrate, and pH were also significant in ANOVA test, these three parameters can be regarded as the most sensitive parameters of artirial pollutants. By the comprehensive com- parison of Ulsan water Quality to that of Kangwon-do, all of the major parameters(pH, KMnO4 consumption, sulfate, chloride and hardness except nitrated were confirmed as being significantly Increased levels.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1925-1928
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• 2007

Water cycle analysis was performed for Gunja basin located in metropolitan Seoul using Aquacycle model in order to assess the problems of urban water cycle. From the water cycle analysis of Gunja basin, it was found that 75% of total rainfall occurred in the form of surface runoff, and groundwater recharge only accounted for about 7%. This suggests serious distortion of water cycle which can be attributed to urbanization. Feasibility analysis of reuse scenarios such as rainwater use and wastewater reuse was then performed to examine their influences on improving the water cycle. From the analysis of water reuse options, it was shown that imported water supply savings of 13% can be achieved through rainwater use, and water supply savings of 31% through wastewater reuse.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.29-30
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• 2018

Recent impervious pavements on roads and sidewalks cause rainwater to not penetrate into the ground, deplete groundwater, or flood the rivers, causing urban flood damage. In order to solve these problems, the amount of installed pitcher block is increasing, but the existing pitcher block is made with cement base and causes many problems. In the cement permeable block, the efflorescene phenomenon occurs due to the acid component, and the pore of the permeable block is clogged and the permeability is lost. As a result, the service life of the pitcher block is shortened and the replacement period is shortened. The purpose of this study is to analyze the basic properties of polymer concrete by replacing cement with polymer in order to solve the problem of cement - based concrete permeable block.

• Environmental Engineering Research
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• 제21권2호
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• pp.211-218
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• 2016

Cheonggye-cheon is a partly restored urban stream located in central Seoul. We monitored fecal contamination using three different fecal indicators, total coliforms (TC), fecal coliforms (FC) and E. coli, to assess differences in each indicator on days of varying weather conditions. Presumptive TC, FC and E. coli colonies were identified by their 16S rRNA sequences. The results showed that enumeration of E. coli provided a better reflection of fecal contamination of the stream than TC and FC. The main sources of contamination were the inflow of fecal-polluted groundwater from the vicinity of a subway line and two inflowing streams. The fecal contamination was worsened on days with heavy rain because untreated sewage from a collecting facility flowed into the stream. Moreover, growth potential of fecal indicator (E. coli) in situ induced by algal exudates was measured. Our results suggest that an appropriate standard based on E. coli rather than TC and FC should be established for improving water quality management strategies of Cheonggye-cheon in the future.

• Ecology and Resilient Infrastructure
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• 제3권2호
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• pp.126-129
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• 2016

도시화로 인해 불투수 면적이 증가하면서 지하 침투량이 감소하고 강우 유출량이 증가하여 도시 침수 발생 가능성이 커지고 지하수 고갈 문제를 발생시키고 있다. 본 연구에서는 가로수 주위에 수분 및 영양을 공급할 수 있는 신개념 특수 가로수 보호판의 설치가 도시 내 침투량 개선에 미치는 효과를 평가하고, 시설의 배치에 따른 침투량 변화를 조사하였다. 침투관이 설치된 신개념 가로수 보호판은 토양으로는 빗물 침투량을 증가시키고 지면 위 수위 상승을 억제하였다. 따라서 개발된 신개념 가로수 보호판은 도시 도로변에서 저영향개발 (LID) 시설로서 효과적으로 적용될 수 있을 것으로 판단되었다.

• Geomechanics and Engineering
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• 제28권6호
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• pp.573-584
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• 2022

Water inrush may occur during seaside urban tunnel excavation. Various factors affect the water inrush, and the water inrush mechanism is complex. In this study, nine evaluation indices having potential effects on water inrush were analysed. Specifically, the geographic and geomorphic conditions, unfavourable geology, distance from the tunnel to sea, strength of the surrounding rock, groundwater level, tidal action, cyclical footage, grouting pressure, and grouting reinforced region were analysed. Furthermore, a two-step interval risk assessment method for water inrush management during seaside urban tunnel excavation was developed by a multi-index system and interval risk assessment comprised of an interval analytic hierarchy process, fuzzy comprehensive evaluation, and relative superiority analysis. The novel assessment method was applied to the Haicang Tunnel successfully. A preliminary interval risk assessment method for water inrush was performed based on engineering geological conditions. As a result, the risk level fell into a risk level IV, which represents a section with high risk. Subsequently, a secondary interval risk assessment method was performed based on engineering geological conditions and construction conditions. The risk level of water inrush is reduced to a risk level II. The results agreed with the current tunnel situation, which verified the reliability of this approach.

• Geomechanics and Engineering
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• 제35권2호
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• pp.109-119
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• 2023

Ground subsidence in urban areas due to excessive development and degraded underground facilities is a serious problem. Geophysical surveys have been conducted to estimate the distribution and scale of cavities and subsidence. In this study, electrical resistivity tomography (ERT) was performed near an area of road subsidence in an urban area. The subsidence arose due to groundwater leakage that carried soil into a neighboring excavation site. The ERT survey line was located between the main subsidence area and an excavation site. Because ERT data are affected by rapid topographic changes and surrounding structures, the influence of the excavation site on the data was analyzed through field-scale numerical modeling. The effect of an excavation should be considered when interpreting ERT data because it can lead to wrong anomalous results. A method for performing 2D inversion after correcting resistivity data for the effect of the excavation site was proposed. This method was initially tested using a field-scale numerical model that included the excavation site and subsurface anomaly, which was a loosened zone, and was then applied to field data. In addition, ERT data were interpreted using an existing in-house 3D algorithm, which considered the effect of excavation sites. The inversion results demonstrated that conductive anomalies in the loosened zone were greater compared to the inversion that did not consider the effects of excavation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권6호
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• pp.9-15
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• 2019

Soil dust emitted from large scale construction sites in urban areas has posed a significant health threats to local residents by exacerbating air quality. Water-spraying (moistening) is commonly practiced to lower the dust emission in construction sites, but its long term effectiveness is highly questionable. In this study, the utility of starch and PVA(polyvinyl alcohol) was investigated in suppression of the soil dust emissions in construction sites in Seoul areas. The efficiency of the two suppressants was tested with test soil sample in a lab-scale wind tunnel box under different concentrations of suppressants and soil textures. Starch and PVA showed the superior ability to suppress soil dust emission as compared to moistening, resulting in PM₁₀ and PM_2.5 lower than the daily limit values of 30 and 15 ㎍/㎥ respectively. PVA showed higher suppression capability than starch for all conditions. The test soils mixed with suppressants also showed dramatically enhanced aggregate stability compared to the non-treated soil.

• 지구물리와물리탐사
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• 제10권4호
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• pp.259-267
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• 2007

정적효과가 포함된 MT 자료를 효율적으로 역산하기 위해 새로운 근사 감도(sensitivity)를 제시하였다. 근사 감도를 이용하여 감도 행렬을 구하는데 필요한 막대한 계산 시간을 합리적인 수준으로 줄이면서 정확한 감도를 이용한 경우와 비슷한 수준의 역산 결과를 얻을 수 있었다. 이 연구에서 제시한 근사 감도 외에 초기 균질 모형에 대한 감도, Broyden 법을 이용하여 업데이트한 감도, 정확한 해에 의존한 감도 등을 여러 가지 조합으로 3차원 역산을 수행할 수 있는 효율적인 방법에 대해 연구하였다. 인공합성자료 및 포항 지역에서 획득한 현장 자료에 대하여 3차원 역산한 결과, 네가지 감도의 조합으로 성공적인 역산이 가능함을 확인하였다. 이로부터 다양한 감도를 적용하여 역산을 수행하는 것이 보다 효율적이고 합리적인 역산 결과를 얻는데 도움이 됨을 알 수 있었다.