• Title/Summary/Keyword: Ground seawater

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The Development of Slag Based Materials for the Reformation of Soft Ground

  • Byeon, Tae-Bong;Kim, Hyung-Suek;Han, Ki-Hyun
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.537-541
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    • 2001
  • For the development of reformation material of soft ground using the LD slag, the relation to the particle condition of LD slag and the pH behavior of slag dissolution water, extraction properties of slag, and origination of white water were investigated. When the LD slag is mixed with sea water, the pH of solution ranged between 9.47 and 10.0. On the other hand, when mixed with distilled water, the pH was about 10.4 to 12.1. For the as-received slag and the aged slag in sea water, a pH of 11.5 to 12.0 was observed when the particle size was less than 0.5mm. For the reoxidized slag in seawater, the pH of the solution was lower than 9.5 when the particle size was bigger than 0.075mm. For the aged slag and reoxidized slag, the pH of the solution remained constant when the addition ratio of sea water to the slag was higher than 500 times. The main elements dissolved from the slag were Ca and Mg ions. When the pH went over 9.0, the white water started to font which was caused by the CaCO$_3$and Mg(OH)$_2$.

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Utilization of induced polarization for predicting ground condition ahead of tunnel face in subsea tunnelling: laboratory test (유도분극을 활용한 해저터널 굴착면 전방 지반상태 예측: 실내실험)

  • Park, Jinho;Lee, Kang-Hyun;Lee, Seong-Won;Ryu, Young-Moo;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.3
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    • pp.383-392
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    • 2015
  • In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

Composite model for seawater intrusion in groundwater and soil salinization due to sea level rise (해수면 상승으로 인한 지하수 해수침투 및 토양 염류화 합성 평가모델)

  • Jung, Euntae;Park, Namsik;Cho, Kwangwoo
    • Journal of Korea Water Resources Association
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    • v.50 no.6
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    • pp.387-395
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    • 2017
  • Sea level rise, accompanied by climate change, is expected to exacerbate seawater intrusion in the coastal groundwater system. As the salinity of saturated groundwater increases, salinity can increase even in the unsaturated soil above the groundwater surface, which may cause crop damage in the agricultural land. The other adverse impact of sea level rise is reduced unsaturated soil thicknesses. In this study, a composite model to assess impacts of sea level rise in coastal agricultural land is proposed. The composite model is based on the combined applications of a three dimensional model for simulating saltwater intrusion into the groundwater and a vertical one dimensional model for simulating unsaturated zone flow and transport. The water level and salinity distribution of groundwater are calculated using the three dimensional seawater intrusion model. At some uppermost nodes, where salinity are higher than the reference value, of the 3D mesh one dimensional unsaturated zone modeling is conducted along the soil layer between the ground water surface and the ground surface. A particular location is judged salinized when the concentration at the root-zone depth exceeds the tolerable salinity for ordinary crops. The developed model is applied to a hypothetical agricultural reclamation land. IPCC RCP 4.5 and 8.5 scenarios were used as sea level rise data. Results are presented for 2050 and 2100. As a result of the study, it is predicted that by 2100 in the climate change scenario RCP 8.5, there will be 7.8% increase in groundwater saltwater-intruded area, 6.0% increase of salinized soil area, and 1.6% in increase in water-logging area.

The Study on Constructing Underground Wall to Prevent Seawater Intrusion on Coastal Areas (지하수댐 물막이벽 시공법과 해안지역 염수침입 방지기술 개선 방안)

  • 부성안;이기철;김진성;정교철;고양수
    • The Journal of Engineering Geology
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    • v.12 no.2
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    • pp.215-234
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    • 2002
  • Groundwater Dam is one of the reliable techniques to get huge amount of groundwater abstraction for municipal, agricultural, drinking, industrial water supply system. It can be a major technique to solve water shortage problems when it based on the sufficient watershed, proper topology, and adequate aquifer distribution and pollution control, Groundwater Dam had initiated its construction by RDC(former KARICO) in early eighties in Korea and 4 of it in total were added more until late eighty. However, this technique has shrunken its application due to gradually decreased yield rate after sever years of construction. After we studied several existing sites precisely, we concluded that the main reason of decreasing yield rate was come form engineering roughness on construction in early nineties. Theoretically, the technique itself seemed to be little detectives however, there were a little application in the fields in Korea. With the recent advance in engineering fields, those defects in construction would be no longer obstacle to construct underground wall and the technique could be a one of major ground water production technique in the future. It is essential to study following items thoroughly before select the appropriate site. The topography and the site of the underground wall, aquifer distribution, the specific technique for wall construction to block groundwater flow effectively and strict quality control during construction are critical. The surface and ground water monitoring data should be collected. Sustainability of the Groundwater Dam with huge groundwater abstraction in long term should be based on the long-term water balance analysis for each site. The water quality, environmental effect analysis and maintenance achedule should be also analyzed and planned in prior. It is suggested that the two consecutive underground wall in the coastal area to prevent seawater intrusion beneath a single wall.

Soil Property of Coastal Soft Ground Considering Geological Property (지질학적 특성을 고려한 해안연약지반의 토질특성)

  • 송무영;김팔규;김연천;류권일
    • The Journal of Engineering Geology
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    • v.7 no.3
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    • pp.217-227
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    • 1997
  • The purpose of this study is to analyze the correlation of soil properties in coastal soft ground. For the purpose of this study, several coastal soft ground areas were selected. Many large scale construction works are being executed and will increase continuously in these soft ground areas. So, soil property in these areas is very important. The grounds forming coastal areas are affected by seawater movement. So, most of these areas consist of alluvium stratum. Therefore, soil properties of eastern and southern coastal areas are very complex. Many laboratory tests were executed with disturbed and undisturbed soil samples. Undisturbed samples were taken by using thin walled tubes and transported into the laboratory with caution, so as not to disturb the sample. The consistent rate of fine-grained content in these areas is over 90%. Also, these areas contain higher water content and clay content. Therefore, knowing these soil properties, it is possible to safely design fabrics and constructions.

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A Fundamental Study of a Neo-Grouting Technology for the Decreasing of a Ground Disaster in a High Water Pressure Conditions (고수압 조건에서의 지반재해 저감을 위한 최신 그라우팅 시공관리 기술 기초연구)

  • Kim, Jin-Chun;Yoo, Byung-Sun;Kang, Hee-Jin;Kwon, Young-Sam
    • Journal of Korean Society of Disaster and Security
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    • v.7 no.1
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    • pp.9-16
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    • 2014
  • In the high water pressure construction conditions, it is important that the failures and damages occurrence in the neighboring ground and impermeable prevention methods (design and construction) for a inflow of seawater into structures. Grouting construction markets include a subway construction, a railway construction, a mountain tunnel construction, a new & reinforced construction of river & reservoir levee with big budget per every years. but, there are economic loss about design and construction management parts because that management criteria is not accurate but depends on experiences. Even though grouting technology are using vitally in the major constructions of national levels, it is still serious about the low-reliability problems and the no-criteria problems. therefor the purpose of this study is that provides the fundamental research about the neo-grouting technology for the decreasing of ground disaster in a high water pressure conditions.

Response of Open-ended Pipe Pile Foundation at Offshore Sites to Seaquake Induced by the Vertical Seismic Excitation of the Seafloor (해저면의 수직 지진 진동에 의해 유발된 해진에 대한 해상 개단 강관 말뚝 기초의 거동)

  • 최용규;남문석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.1
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    • pp.11-21
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    • 1998
  • During an earthquake, there are three main components of excitation : horizontal excitation of the ground, vertical excitation of the pile due to superstructure feedback produced by vertical excitation of the ground, and the seawater excitation induced by the vertical ground shaking, that is, "the seaquake." These excitations could have effects on the soil plugs in open-ended pie piles installed at offshore sites. In this study, seaquake excitation induced by the vertical ground shaking was simulated by pulsing the water pressure at the seabed. During a seaquake, due to the induced excess porewater pressure and pressure gradients in the soil, the capacity of open-ended pipe piles installed in a simulated sea depth of greate than 220 m was reduced serevely and the soil plugging resistance was degraded by more than 80% The soil plug was failed because of eh upward seepage forces that developed in the soil plug due to excess pore water pressure produced in the bottom of the soil plug during the seaquake, The compressive capacity of ar open-ended pile in a simulated sea depth of less than 220 m was reduced only by about 10% and the soil plug resistance was degraded by less than 5%.s than 5%.

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A Study on the Geotechnical Characteristics of Jeju Area Using Field Tests (현장시험을 이용한 제주지역의 지질특성에 관한 연구)

  • Byung Jo Yoon;Sung Yun Park;Seung Jun Lee
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.769-777
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    • 2022
  • Purpose: This study analyzes and studies the characteristics of the Jeju area and uses them as basic data such as construction method design in the future development project. Method: Based on the ground survey data of the construction conducted in Jeju, the depth, relative density, N value, function state, color tone, groundwater level, and compressive strength were analyzed and studied. Result: Studies show that Jeju has columnar joints consisting of ancient volcanic activity and rapid cooling by nearby seawater, thick sand layers found on the coast, and clinker layers and Seogwipo layers formed by Mercury volcanic activity. Conclusion: It is hoped that it will be used as data for selecting basic design and basic construction method by understanding the special ground form of Jeju area and reflecting its characteristics well when designing construction.

Comparative Analysis of Seawater Desalination Technology in Korea and Overseas (국내 및 해외의 해수담수화 기술 비교분석)

  • Hwang, Moon-Hyun;Kim, In S.
    • Journal of Korean Society of Environmental Engineers
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    • v.38 no.5
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    • pp.255-268
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    • 2016
  • Climate change has increased the need to secure a new water resource in addition to the traditional water resources such as surface water and ground water. The seawater desalination market is growing sharply in accordance with this situation in Korea, "seawater engineering & architecture of high efficiency reverse osmosis (SEAHERO)" program was launched in 2007 to keep pace with world market trend. SEAHERO program was completed in 2014, contributed to turn the domestic technology in evaporative desalination technology to RO desalination technology. Currently, it is investigated that the average specific energy consumption of the whole RO plant is around $3.5kWh/m^3$. The Busan Gi-jang plant has shown $3.7{\sim}4.0kWh/m^3$, including operational electricity for plant and maintenance building. Although not world top level, domestic RO technology is considered to be able to compete in desalination market. Separately, many researchers in the world are developing new technologies for energy savings. Various processes, forward osmosis (FO), membrane distillation (MD) process are expected to compete with RO in the future market. In Korea, FO-RO hybrid process, MD and pressure retarded osmosis (PRO) process are under development through the research program in Ministry of Land, Infrastructure and Transport (MOLIT). The desalination technology level is expected to decrease to $2.5kWh/m^3$.

Reactive separation of boron using a liquid membrane of diol in vegetable oil

  • Hossain, Md. M.;Maraqa, M.A.
    • Membrane and Water Treatment
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    • v.8 no.1
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    • pp.19-34
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    • 2017
  • Boron exists in dilute concentrations in sea water, ground water and waste waters. Reactive liquid extraction can be used for removing boron to make the treated water suitable for drinking and irrigation, with its final concentration less than 0.5 ppm. The results of equilibrium experiments are reported on the removal of boron using 2-butyl-2-ethyl-1, 3-propanediol (BEPD as a nonionic carrier) in sunflower oil, a non-traditional solvent. The results of removal of boron from aqueous solutions in the concentration range 0.5-20 ppm are presented. It is shown that this new liquid membrane system, is able to remove boron from ground waters at their natural pH of 6-8 (without any chemical addition for pH adjustments). The removal efficiency is good when the process is upgraded to a hollow-fibre membrane contactor and approximately 45% boron can be removed in a single-stage contact. There are additional advantages of this new approach that includes reduced operational health and safety and environmental issues. The results reported here provide guidelines to the development of boron removal process using renewable, biodegradable, safe and cheap solvent system such as sunflower oil.