• Title/Summary/Keyword: ground treatment

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A Case Study on Soft Soil Treatment Design and Construction in Vietnam (베트남지역에서의 연약지반 개량 설계.시공 사례)

  • Yoon, Dong-Duk;Cho, Sung-Han;Seo, Won-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.336-345
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    • 2010
  • GS E&C was awarded the contract for the construction of Hanoi - Hai Phong Expressway Package EX-7 from Station Km 72+000 to Station Km 81+300 in December 2008. This project is the $7^{th}$ contract package of the 105.5 km long expressway near Hai Phong city, which includes a FCM-styled bridge along with high embankments over soft ground. For these high embankments, there is a need to treat the soft soil for improving the overall stability during construction and for reducing the post-construction settlement of the expressway. The Designer of this project had adopted four (4) different types of ground improvement techniques to treat the soft ground, including the prefabricated vertical drains (PVD), sand drains (SD), pack drains (PD, or sometimes called packed sand drains), and sand compaction piles (SCP). The main focus of soft soil treatment should be paid attention to the residual settlement after construction. In current design, however, it appeared that the secondary compression (or creep) of the improved soil layer and the consolidation settlement of the lower untreated compressible soil layer have been neglected in the estimation of the post-construction settlement. These uncalculated residual settlements may not only unsatisfy the design criteria but also raise serious problems during service period of this expressway. In this paper, the subsoil condition and current design were reviewed focusing on the employed soft soil treatment method and expected residual settlement.

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Inactivation Efficiency of Escherichia coli and Listeria monocytogenes in Ground Pork by Combination of Natural Food Ingredients and High Pressure Processing

  • Jung, Samooel;Yun, Hye-Jeong;Kim, Hyun-Joo;Ham, Jun-Sang;Kim, Il-Suk;Lee, Moo-Ha;Jo, Cheorun
    • Food Science of Animal Resources
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    • v.32 no.1
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    • pp.1-5
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    • 2012
  • The objective of this study was to examine the effects of a combined treatment regarding antimicrobial food ingredients and high pressure processing (HP) on the inactivation efficiency of Escherichia coli and Listeria monocytogenes inoculated into ground pork. Ethanol extracted from garlic, leeks, onions, and ginger powder was prepared. Half of the prepared powder was irradiated at 5 kGy to see the effect of pasteurization before addition. The prepared food ingredients were added into radiation-sterilized ground pork (1%, w/w), and inoculated with E. coli and L. monocytogenes. The samples were vacuum-packed and applied with HP at 0.1 (control), 300, 450, and 600 MPa. Microbial log reduction increased with the increase of pressure up to 600 MPa. With minor exceptions, overall efficiency of HP treatment with regards to inactivation of pathogens increased. Inoculated microorganisms showed approximately 7-8 Log reductions by 600 MPa, except for L. monocytogenes treated with garlic (5.7 Log reductions). The E. coli reduction in ground pork mixed with ethanol extracted garlic showed the highest efficiency (1.86) compared to leeks (1.25-1.31), onions (1.17-1.44), and ginger (1.50-1.82) when treated at an HP of 450 MPa. There was no evidence for the advantage of pasteurization concerning the food ingredients before addition of antimicrobial food ingredients and HP. Results demonstrate that the combination of antimicrobial food ingredients and HP treatment may help improve the efficiency of sterilization in meat systems.

Analysis on the Safety of Structure and Economics of Replacement Method Using Rock Debris in the Soft Ground - Case Study of Miho Stream Crossing Road in Cheongju City (연약지반 암버럭 치환공법의 구조물 안정성과 경제성 분석 - 청주시 미호천 횡단도로를 대상으로)

  • Heo, Kang Kug;Park, Hyung Keun;Ahn, Byung Chul;Min, Byeong Uk
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.4
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    • pp.705-713
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    • 2016
  • For the soft ground construction, the factors not considered in the design stage occurs in the construction stage so that they cause the increase of the construction cost due to the structural stability and the design change. The subject of the study is the construction section of the industrial complex access road made in the Ochang region of Chungcheongbuk-do. The study is concerned with selecting the soft ground handling method such as the replacement method using rock debris and the surcharge reflecting the service load as the soft ground handling measure and analyzing the effect of reducing the construction cost with the stability of structures and the reduction of the construction period. The soft ground in the study section consists of sandy and cohesive soil and is 2.4m to 5.5m deep. It is distributed unevenly between the 1.5m to 5.9m stratums under the ground surface. Settlement is not serious, but the future uneven settlement and difference are expected so that the future settlement behavior is estimated by analyzing the site measurement results after the soft ground treatment. Moreover, in consideration of the regional characteristics and economic efficiency, soil with good quality is replaced with rock debris as the replacement material so that 29% of the construction cost is reduced due to the increase of stability and the reduction of duration. If the estimation of the dispersion of the pore water pressure within the dam body and the change of the underground water level and the relation of the actually measured soft ground with consolidation is studied further on the basis of the study, it is expected that the behavior of the soft ground will be correctly estimated in various site conditions.

Effects of flower removal on Growth and Content of essential oil in Atractylodes macrocephala Koidz (화기제거가 백출(Atractylodes macrocephala Koidz)의 생육 및 정유 함량에 미치는 영향)

  • 김수용;권오흔;조지형;임재하
    • Korean Journal of Plant Resources
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    • v.14 no.2
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    • pp.152-156
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    • 2001
  • This study was conducted to investigate the flower organ removal effect on Atractylodes macrocephala Koidz which was introduced from China. The results were summarized as follows; The plant height of Flower Organ Cutting(F.O.N.C.) treatment short by 1.7∼2.5 cm compared to Flower Organ Non-Cutting(F.O.N.C.) treatment. But number of stem and stem diameter of F.0.C treatment were similar to that of F.O.N.C. treatment. The fresh weight of above-ground part of F.O.N.C. treatment was decreased 48∼60% compare to F.O.C. treatments. The later was period of F.O.C., the higher was fresh weight of above-ground part. The growth of underground part was more F.O.C. at July 15 and Aug. 20 treatments than F.O.N.D treatment. The dry rhizome yield of F.O.C. at July 15 treatment was increased 40% compare to F.O.N.D treatment. Essential oil content of F.O.C. at July 15 treatment was increased 12% compare to F.O.N.D treatment.

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Research on the Surface Improvement of High Soft Ground Using Calibration Chamber Test (모형토조실험에 의한 초연약지반의 표층개량에 관한 연구)

  • Bang, Seongtaek;Yeon, Yongheum
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.5
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    • pp.39-46
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    • 2019
  • Most of the soil used for reclamation is marine clay generated from dredging construction.The soft ground made of dredged clay has high water content and high compressibility, so the bearing capacity of the ground is very weak and it is difficult to enter the ground improvement equipment. Therefore, surface hardening treatment method is used to enter equipment prior to full-scale civil engineering work, and stabilizer is mainly used for cement series. Cement-based stabilizers have the advantage of improving the ground in a short period of time and have excellent economic efficiency, but they are disadvantageous in that they cause environmental problems due to leaching of heavy metals such as hexavalent chromium. In this study, environmental effects evaluation of dredged clay mixed with normal portland cement and environmentally friendly stabilizer was evaluated, and uniaxial compressive strength test and indoor model test were conducted to confirm the bearing capacity characteristics of the solidified layer.

Removal Characteristics of Iron, Manganese and Organics in Ground Water Using Ozonation (오존을 이용한 지하수의 철.망간 및 유기물 제거특성)

  • 선창욱;우달식;남상호
    • Journal of environmental and Sanitary engineering
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    • v.12 no.2
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    • pp.43-49
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    • 1997
  • Iron and manganese problems in ground water affect far more water systems than almost any other water quality concern. The purpose of this study is to find the optimum condition of ozonation for the removal of dissolved iron, manganese and other organics in the polluted ground water. We proposed 4mg/l, 8mg/l as optimum ozone dose for the removal of $Fe^{2+},{\;}Mn^{2+}$, respectively. The removal efficiencies of $COD_{Mn}$ and $COD_{Cr}$ in ozone dose of 2mg/l - 6mg/l were about 40-50%. The removal efficiency of $NH_{3}-N$ was about 30-40% at pH8.5. In conclusion, it needs further systematic study and research concerned to treatability of $Fe^{2+},{\;}Mn^{2+}$ and biodegradability of organic compounds using Ozonation followed by biological filtration process in ground water treatment train.

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A strengthening effect based on a grid size of a bamboo-mat and a model-test for the understanding on ground failure. (대나무매트의 격자크기에 따른 보강효과 및 지반 파괴형상 파악을 위한 모형시험)

  • Lee, Ji-Hun;Kim, Seung-Gon;Kim, Woo-Jin;Kim, Jong-Ryeol;Kang, Hee-Bog
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1673-1677
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    • 2008
  • A method of construction with a basis treatment that uses a latticed bamboo mat puts bamboo's peculiarity and bamboo mat's bending substance to use, and a latticed bamboo mat equally distributes to embankment loading in a basis ground. Therefore it prevents ground destruction by an ill-balanced load and an irregular ground subsidence, and it makes safety system. This investigation make progress a soil box model by a dredged reclamation ground of west and south sea at domestic area, and make a comparative study and analyze the strengthening effect based on a grid size of a bamboo-mat and ground failure that it will use in the field.

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Antimicrobial Effect of Buffered Sodium Citrate (BSC) on Foodborne Pathogens in Liquid Media and Ground Beef

  • Ryu, Si-Hyun;Fung, Daniel -Y. C.
    • Preventive Nutrition and Food Science
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    • v.15 no.3
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    • pp.239-243
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    • 2010
  • The antimicrobial effects of a commercially available, buffered sodium citrate (BSC) were evaluated for the reduction of total aerobic bacteria count, Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus in a liquid medium and ground beef. BSC at 0, 1, 2 and 4.8% (wt/vol) or 0, 3, and 4.8% (wt/wt) was mixed into inoculated brain heart infusion (BHI) broth and ground beef (80% lean), respectively. BSC at concentrations of 1 and 2% did not inhibit growth of the pathogens tested in BHI broth. E. coli O157:H7 in BHI broth with 4.8% BSC was significantly reduced (p<0.05) by 3~4 log CFU/mL compared with the control for up to 4 days. At 4.8%, BSC treatment of ground beef most significantly reduced (p<0.05) total aerobic count and E. coli O157:H7 by 2.1 and 2.0 log CFU/g, respectively. This study indicates that the legally allowable level of 1.3% (wt/wt) BSC is not effective for reducing the pathogens tested in ground beef stored at $7^{\circ}C$.

A study on the Characteristic of Waste Ground Rubber Tire Powders with Pre-treatment Process for Recycling (전처리 공정에 따른 폐타이어 재생 고무분말의 특성연구)

  • Park, Jongmoon;An, Ju-Young;Park, Jin-Eui;Bang, DaeSuk;Kim, Bong-Suk;Oh, Myung-Hoon
    • Resources Recycling
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    • v.24 no.2
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    • pp.55-61
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    • 2015
  • In this study, mechanical properties of waste ground rubber tire powder were investigated to evaluate the influence of pre-treatment process for recycling. The tensile test, fracture test and morphology observation were carried out using various kinds of waste ground tire powders, which were produced by grinding and devulcanization process, respectively. As a results, it was found that the produced rubber powder through grinding process increased its tensile strength and elongation with decreasing particle size because of decreasing surface area. Devulcanized rubber powder also increased its tensile strength and elongation by de-crosslink with sulfur. It could be also suggested that devulcanization treatment after grinding process was more efficient recycling process for both increasing tensile property and fracture elongation of waste ground rubber tire powders.