• Title/Summary/Keyword: Dredge and Reclamation

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The historical process of dredge fishery according to the construction of the Saemangeum Dike in Jeollabuk-do, Korea (새만금방조제 건설로 인한 전라북도 형망어업의 변천과정)

  • CHOI, Jong-deok;RYU, Dong-ki
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.4
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    • pp.327-336
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    • 2017
  • Fishing dredge in Jeollabuk-do began to become widespread in the 1960s and has continued to catch diverse kinds of shellfish in the productive fishing grounds around Dongjin River, Mangyeong River and Geum River estuaries. Since the 1970s, the construction of various large-scale industrial complex and the implementation of Saemangeum reclamation project have resulted in a decrease in main fishing areas and a sharp decline in shellfish production. As a result, dredge fishery has faced many difficulties. Dredge fishery in Jeollabuk-do is carried out with a total of 30 fishing permits as of 2016. Surf clams, hen clams, bladder moon snails, and common orient clams were mainly caught before the construction of Saemangeum dike while comb pen shells, purple whelks and ark shells are mainly caught afterwards. Inside the Saemangeum dike, most fish species have disappeared due to low water level and low salinity, and littleneck clams are caught using a jet pump type of fishing dredge. Outside the dike, the diversity of shellfish species has been reduced; comb pen shells are mainly caught. In this process, a lot of friction occurs due to the use of a reformatted dredge. Therefore, a lot of research needs to be conducted in the near future.

A Study on the Determination of Loss Ratio in Dredged Soils (준설토의 유실율 결정에 관한 연구)

  • 김석열;김승욱;노종구
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.606-611
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    • 1999
  • Recently , the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materialss. The method of hydraulic fill i recalmation is executed by transporting the mixture of water -soil particles into a relcaimed land through dredging pipes, then the dredged soil particels settle down in thewater orflow over an out flow weir with the water. The amount of the volume reductions of dredged soil is considered the sum of the overall settlement by descication shrinkage and self-weigth consolidation and the loss of soil particles flow over a weir. In the present study, hydrometer analysis was performed with the soil samples obtained bofore and after dredging to estimate the amount of soil particles residual at reclaimed area and the loss of soil particles , then it was suggested the method of determining the loss ratio of dredged soils from the tests results. The hydrometer analysis of in-situ soil samples showed that the loss ratio of dredged soils is lowest at the nearest point to dredge pipe and highest at the nearest point of out flow weir.

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Bearing Capacity and Settlement of Reclaimed Land by Utilizing Waste Lime (폐석회를 활용한 성토매립지반의 지지력 및 침하특성에 관한 연구)

  • 신은철;오영인
    • Journal of the Korean Geotechnical Society
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    • v.15 no.4
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    • pp.175-184
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    • 1999
  • Several major land reclamation projects such as the Inchon International Airport construction, Songdo New City construction, LNG Tank and LPG storage construction are underway along the coastal line of Inchon in Korea. This study was carried out to investigate the feasible use of waste lime in the land reclamation projects. Waste lime (hydrated lime) used in this study is produced as a by-product in the manufacturing process of $Na_2CO_3$ from local chemical factory in Inchon. This study presents the characteristics of bearing capacity and settlement on the ground formed by layers of waste lime and dredged soil. From the laboratory and in-situ plate load test, the ultimate bearing capacity by in-situ test was 1.25~1.37 times higher than that of the theoretical ultimate bearing capacity. Based on the settlement analysis by Magset- II, the total settlement of layered ground steadly increased up to the ratio of waste lime depth 0.2 and therefore rapidly increased with the increase of waste lime depth. The results of the present study indicate that the ratio of waste lime depth for reclamation work is about 0.2.

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A Study on Hardening Zone by Vacuum Consolidation Drainage Method (진공압밀 배수공법에 의한 Hardening Zone에 대한 연구)

  • Chung, Youn-In;Kim, Hee-Joong;Chang, Chun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.3
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    • pp.197-205
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    • 2004
  • The relationships were studied between the range of hardening zone and the intensity of vacuum pressure in case of applying vacuum consolidation drainage method for soil improvement. A testing apparatus was made to measure the range of hardening zone varying the water content and the intensity of vacuum pressure for 3 different the highly compressible dredged clays(Gwangyang, Busan and Mokpo). In case of applying high vacuum pressure, the hardening zone is not spreaded as compared to low vacuum pressure because of the clogging of drainage and developed hardening zone near the drainage.

An Experimental Research About Settling and Consolidation Characteristic of Dredged Soil in West Coast (서해안 준설토의 침강압밀특성에 관한 실험적 연구)

  • Lee, Seung-Ho;Lee, Jeong-Hak
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.5
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    • pp.29-36
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    • 2011
  • In this study, settling experiment was performed about cohesive and sandy soils among representative sample expected to dredge and dump for analysis of settling and consolidation characteristic. The analysis showed the definite difference between cohesive soils and sandy soils of relationships with settling and consolidation coefficient, a water content, interfacial heights. But directly after a dredged reclamation, prediction results about a initial volume change showed that cohesive soil of a water content change was decreased rapidly as time goes by, but sandy soils made no difference in a water content change. Results were compared and analyzed with the settling and consolidation coefficient and a initial settling velocity by real soil amounts for a feasibility check about test conditions applied to these experiment: we judge that test conditions are appropriate, each material by such these analyses suggests the scope of settling and consolidation coefficient, average and the representative relational formula.

A Preliminary Investigation on Pozzolanic Activity of Dredged Sea Soil (소성 준설토의 포졸란 반응성에 대한 기초 연구)

  • Kim, Ji-Hyun;Moon, Hoon;Chung, Chul-Woo;Lee, Jae-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.6
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    • pp.531-536
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    • 2014
  • Recently, the amounts of dredge sea soil in south Korea have been increasing because of various maintenance works at harbors and rivers. Dredged sea soil contains various contaminants. Hence, prior to recycling the dredged sea soil, the various contaminants should be removed to prevent a secondary contamination due to the leaching of hazardous chemicals. Pretreated dredged sea soil can be buried under the ground or used for land reclamation. In this study, however, pretreated dredged sea soil was used to investigate the level of pozzolanic activity. The properties of pretreated dredged sea soil were investigated, the method for heat treatment was determined, and the compressive strength of mortar using dredged sea soil was examined. According to the XRF result, the main components of dredged sea soil were $SiO_2$ of over 55%, and $Al_2O_3$ and $SO_3$ of some amounts. Results from XRD and TG/DTA showed that pretreated dredged sea soil can be used as a pozzolanic material. When dredged sea soil was thermally treated for 90 min at $550^{\circ}C$, a compressive strength result was similar to that of control mortar.