• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.377-383
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• 2000

The composition of primary minerals of sand fractions and secondary minerals of clay fractions were investigated on the polder soils developed from alluvio-marine deposits near to Sapgyo-lake, constructed a sea dike across river estuary located in the west coast. The effects of a topographical sequence on the physico-chemical properties and mineralogical characteristics were evaluated using XRD, DTA, and TG with the chemical composition of $H^+$ saturated clays. Soils located on the seashore side were more silt fraction, higher pH and exchangeable cations than the others. The dominant minerals of soil parent materials are in the order of quartz, feldspars, micas, chlorite and amphibole. According to the greater distance from the lake, the amount of 1:1 minerals increased, but 2:1 minerals decreased. The dominant clay minerals of polder soils are kaolinite, vermiculite and illite. Hydroxy interlayer minerals are abundant in the clay fractions derived from the soil parent materials which have relatively low soil pH.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.224-235
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• 2014

Changes in the interactions among incident ocean water waves, coastal debris (marine debris), and the back vegetation zone line on a natural sandy beach on the island of Jinu-do in the Nakdong river estuary were investigated. The study involved a cross-sectional field survey of the beach, numerical modeling of incident ocean water waves, field observations of the distribution of coastal debris, and vegetation zone line tracking using GPS. The conclusions of this study can be summarized as follows: (1) The ground level of the swash zone (sandy beach) on Jinu-do is rising, and the vegetation zone line, which is the boundary of the coastal sand dunes, shows a tendency to move forward toward the open sea. The vegetation zone line is developing particularly strongly in the offshore direction in areas where the ground level is elevated by more than 1.5 m. (2) The spatial distributions of incident waves differed due to variations in the water depth at the front of the beach, and the wave run-up in the swash zone also displayed complex spatial variations. With a large wave run-up, coastal debris may reach the vegetation zone line, but if the run-up is smaller, coastal debris is more likely to deposit in the form of an independent island on the beach. The deposited coastal debris can then become a factor determining which vegetation zone line advances or retreats. Finally, based on the results of this investigation, a schematic concept of the mechanisms of interaction between the coastal debris and the coastal vegetation zone line due to wave action was derived.

• Journal of the Korean Geotechnical Society
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• v.22 no.9
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• pp.61-68
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• 2006

Recently the large scale civil engineering projects are being implemented by reclaiming the sea or utilizing seashore and river embankment areas. The reclaimed land and utilized seashore are mostly soft ground that doesn't have sufficient bearing capacity. This soft ground consists of fine-grained soil such as clayey and silty soils or large void soil like peat or loose sand. It has high ground water table and it may cause the failure and crock of building foundation by uplift pressure and ground water leakage. In this study, the permittivity and the transmissivity were evaluated with the applied normal pressure in the laboratory. The laboratory model tests were conducted by utilizing geocomposite drainage system for draining the water out to release the uplift pressure. The soil used in the laboratory drainage test was dredged soil from the reclaimed land where uplift pressure problems can arise in soil condition. Geocomposite drainage system was installed at the bottom of apparatus and dredged soil was layered with compaction. Subsequently the water pressure was supplied from the top of specimen and the quantities of drainage and the pore water pressure were measured at each step water pressure. The results of laboratory measurements were compared with theoretical values. For the evaluation of propriety of laboratory drainage test, 2-D finite elements analysis that can analyze the distribution and the transferring of pore water pressure was conducted and compared with laboratory test results.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.581-594
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• 2021

In 2020, about 132 million m³ of aggregate was produced in Korea. Of the total domestic aggregates produced in 2020, about 33.3 % was sand and about 66.7% was gravel. It estimated that of the 132 million m³ of aggregates in Korea in 2020, about 52% was produced by screening crushed aggregate, by 36% by forest aggregate, 3% by land aggregate, 5.6% by sea aggregate and 2.5% by washing each other, and 0.4% by river aggregate. This indicates that screening crushed aggregate and forest aggregate are the main producers of domestic aggregates. Leading producing metropolitan cities were Gyeonggi-do, Gyeongsangnam-do, Chungcheongbuk-do, Gangwon-do, Chungcheongnam-do, Incheon in order decreasing volume, which together accounted for about 72.4% of total product. In 2020, aggregates were produced in 153 cities, about 67% of the 231 cities of Korea, 38 local governments have developed aggregates of more than 1 million m³, and the combined production of the 38 cities accounted for about 65% of national total. This means that the aggregate extraction trend of local governments is becoming larger and more concentrated. In 2020, at 153 local governments, a total of 889 operations produced aggregates with 420 operations by permission, 469 operations by declaration. A review of production by size of operation indicated that about 17 million m³ (12.8% of the total aggregate) was produced by 14 operations reporting production of more than 1 million m³. In about 420 operations, the maximum period of permit is 32 years to at least 2 months. When the remaining period of permit is taken into account, only about 55% of active operations can be developed the aggregate after 2021. In order to maintain the permitted aggregate volume by 2020 level, it will be necessary to obtain an extension permit or find new operation sites for at least 200 or more operations.