• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.251-268
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• 1986

Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.25-35
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• 1981

Some physical and chemical properties of forest soils in Korea were analyzed for providing the reasonable management methods of forest lands, Among 375 soil series surveyed until 1979, 93 soil series of forest soils were classified and analyzed according to their characteristics. Firstly soil data were classified into 5 categories by weathered products and secondly were classified and analyzed by parent rocks. The results are as follows: 1) In forest soils characterized by weathered products volcanic ash soils were proved to be the most fertile and alluvial soils were turned out to be the most infertile soils. Residual soils on mountain and hill were mostly on the average in all kinds of soil properties analyzed except total soil depth. 2) Igneous rocks developed rather infertile soils containing large amount of organic matter and available $P_2O_5$ with relatively deep soil depth and strong acidity. On the other hand sedimentary rocks produced rather shallow soils containing small amount of organic matter and available $P_2O_5$ but they were relatively fertile with weak acidity. 3) Among igneous rocks basalt and trachyte produced very fertile soils and granite and andesite produced slightly infertile soils. 4) Among sedimentary rocks limestone soils had high fertility neutral in acidity but low amount of available $P_2O_5$ 6) Alluvial sand produced generally very infertile soils with great soil depth comparing with the arable alluvial land with high fertility.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.81-85
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• 1996

Tentative consolidation criteria, a kind of land suitability classification, was established for cultivated upland soils. The criteria were composed of systematically quantified individual soil properties such as physiography(relief), slope, available soil depth etc., and local features such as soil complexity, mapping unit separation, width/length ratio etc. The criteria was applied to upland soils in granite area, and sedimentary rock area. It was clear that the comparison of local features among candidated areas, and classification of suitability classes for land consolidation of upland soils was satisfactory for selection. The status of the areas classified to "Well suitable" were distributed on alluvial plains or less dissected rollings with lower complexity of soils occurred and extended acreage in each mapping unit. On the other hand, the areas classified as "Unsuitable" were distributed on the elongated narrow valleys with quite divided mapping units by paddy fields on the valley bottom.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.79-86
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• 2015

Korean territories has formed about 70% of mountainous areas that have acidified serious level to average pH 4-5. There are a number of abandoned metal mines about 1,000 in Korea. However, mine tailings and waste rock included heavy metals are exposed to long-term environment without prevention facility or treatment system. Thus, ongoing management and monitoring of soil environment are required. Most of abandoned mine scattered in forest areas of slopes. Soil erosion due to continuous rainfall in the slopy areas can cause the secondary pollution by the influence eutrophication of water system and the productivity loss of the plant. Therefore, this study would like to estimate pH leaching rate by artificial rainfall using waste neutralization-agent in lysimeter. Moreover, the potentially of secondary pollution related to precipitation is figured out through the experiments, and the optimal planting methods would examinate after neutralizing treatment in soil. Experiments composed three kinds of lysimeter; lysimeter 1 had filled only acidic soil, lysimeter 2 had neutralized soil, and lysimeter 3 had planting plants after neutralized soil. In the results, lysimeter 2 showed the lowest pH leaching, and there is not specific relativity with pH leaching of the seasonal characteristics.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.163-163
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• 2003

The study area, Kwangneung Experiment Forest (KEF) is located on the west-central portion of Korean peninsula and belongs to a cool-temperate broadleaved forest zone. At the old-growth deciduous forest near Soribong-peak (533.1m) in KEF, we have established a permanent plot and a flux tower, and the site was registered as a KLTER site and also a KoFlux site. In this study, we aimed to present basic ecological characteristics and synthetic data of carbon budgets and flows, and some monitoring data which are essential for providing important parameters and validation data for the forest dynamics models or biogeochemical dynamics models to predict or interpolate spatially the changes in forest ecosystem structure and function. We made a stemmap of trees in 1 ha plot and analyzed forest stand structure and physical and chemical soil characteristics, and estimated carbon budgets by forest components (tree biomass, soils, litter and so on). Dominant tree species were Quercus serrata and Carpinus laxiflora, and accompanied by Q. aliena, Carpinus cordata, and so on. As a result of a field survey of the plot, density of the trees larger than 2cm in DBH was 1,473 trees per ha, total biomass 261.2 tons/ha, and basal area 28.0 m2/ha. Parent rock type is granite gneiss. Soil type is brown forest soil (alfisols in USDA system), and the depth is from 38 to 66cm. Soil texture is loam or sandy loam, and its pH was from 4.2 to 5.0 in the surface layer, and from 4.8 to 5.2 in the subsurface layer. Seasonal changes in LAI were measured by hemispherical photography at the l.2m height, and the maximum was 3.65. And the spatial distributions of volumetric soil moisture contents and LAIs of the plot were measured. Litterfall was collected in circular littertraps (collecting area： 0.25m2) and mass loss rates and nutrient release patterns in decomposing litter were estimated using the litterbag technique employing 30cm30cm nylon bags with l.5mm mesh size. Total annual litterfall was 5,627 kg/ha/year and leaf litter accounted for 61% of the litterfall. The leaf litter quantity was highest in Quercus serrata, followed by Carpinus laxiflora and C. cordata, etc. Mass loss from decomposing leaf litter was more rapid in C. laxiflora and C. cordata than in Q. serrata litter. About 77% of C. laxiflora and 84% of C. cordata litter disappeared, while about 48% in Q. serrata litter lost over two years. The carbon pool in living tree biomass including below ground biomass was 136 tons C/ha, and 5.6 tons C/ha is stored in the litter layer, and about 92.0 tons C/ha in the soil to the 30cm in depth. Totally more than about 233.6 tons C/ha was stored in DK site. And then we have drawn a schematic diagram of carbon budgets and flows in each compartment of the KEF site.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.1-15
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• 2010

In this study, the reduction factor of the code-defined site coefficient due to the embedment of a foundation was estimated for the seismic analysis of a building built on a soft soil site. This was done by utilizing the in-house finite element software P3DASS, which has the capability of pseudo 3D seismic analysis with nonlinear soil layers. A 30m thick soft soil site laid on the rock was assumed to be homogeneous, elastic, viscous and isotropic, and equivalent circular rigid foundations with radii of 10-70m were considered to be embedded at 0, 10, 20 and 30m in the soil layer. Seismic analyses were performed with 7 bedrock earthquake records deconvoluted from the outcrop records of which the effective ground acceleration was scaled to 0.1g. The study results showed that the site coefficients are gradually reduced except in the case of a small foundation embedded deeply in the weak soil layer, and it was estimated that the deviation of the site coefficients due to the foundation size was not significant. The standard reduction factor due to the foundation embedment were calculated adding the standard deviation to the average of 5 reduction factors calculated for 5 different foundation radii. Standard reduction factors for the site amplification factor were proposed for the practical amplification and the codes of KBC, etc., in accordance with the average shear wave velocity of the site, and the site class.

• Korean Journal of Organic Agriculture
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• v.14 no.2
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• pp.205-217
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• 2006

This research was carried out to investigate the effects of some organic materials such as rice straw, compost, hairy vetch, phosphate rock, magnesium lime powder and ash in the organic paddy fields, and also to develope the new technique for better soil management using described materials. The results are as follows; Height and tiller of rice plants were higher in chemical fertilizer than rice straw or compost, however, those of rice plants in hairy vetch-rice cropping system reached to chemical fertilizer. The Eh value of soil has decreased consecutively since on 30th, May because of the rising of soil temperature by an increase in the activity of microbes. As a result of measuring yield and yield components, there is not significant difference between treatment. The application of organic materials enriched the contents of available phosphorus, exchangible potassium and calcium in soil, and, also improved the physical properties such as pore space rates and bulk density. From the viewpoint of soil management technology in organic paddy fields, the application of rice straw or organic compost might cause the decrease of yield compared with conventional cultivation system, chemical fertilizer, however, the application of hairy vetch residues of soil compensated for growth and yield as well as improved the physicochemical property. Therefore, it is assumed that the cultivation of hairy vetch for winter season can be one of the useful methods for organic farming system.

• Journal of the Mineralogical Society of Korea
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• v.31 no.3
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• pp.193-213
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• 2018

Soil geochemical exploration to check anomalies related to mineralization was carried out targeting around Quy Hop area within Nghe An province, Northern Vietnam. The interval of sampling are horizontal 250 m with 13 line and longitudinal 300 m with 25 line, resulting in 325 soil samples. Based on the result of soil geochemical exploration, the pitting survey was carried out targeting the grid point with high TREO content, resulting in 73 soil samples within 8 pits. The geology of the survey area are consisted of Ban Chieng biotite granite complex intruding Bu Khang formation comprising of schist, gneiss and limestone. In order to elucidate the source rock of monazite and xenotime confirmed from heavy sand, soil geochemical exploration was carried out. By ICP-MS result of soil samples, total REE oxide content of background amount is about 1.4 times of crustal abundance, depleting the light rare earth (about 0.2 times) and enriching the heavy rare earth (about 1.5 times). By ICP-MS result of pit soil samples, we identified TREO more than 1,000 ppm in 6 pits. It may be considered that REE ore bodies may develop in NE-SW direction, compared with the geochemical results of Quy Chau area.

• Economic and Environmental Geology
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• v.32 no.6
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• pp.611-631
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• 1999

Enviromental geochemisty and heary metal contamination at the Kongjueil mine creek were underaken on the basis of physicohemical properties and mineralogy for various kinds of water (surface, mine and ground water),soil, precipitate and sediment collected of April and December in 1998. Hydrgeochemical composition of the water samples are characterized by relatively significant enricant of Ca+Na, alkiali ions $NO_3$ and Cl inground and surfore water, wheras the mine waters are relatively eneripheral water of the mining creek have the characteristics of the (Ca+Mg)-$(HCO_3+SO_4)$type. The pH of the mine water is high acidity (3.24)and high EC (613$\mu$S/cm)compared with those of surface and ground water. The range of $\delta$D and $\delta^{18}O$ values (relative to SMOW) in the waters are shpwn in -50.2 to -61.6% and -7.0 to -8.6$\textperthousand$(d value=5.8 to 8.7). Using computer program, saturation index of albite, calcite, dolomite in mine water are nearly saturated. The gibbiste, kaolinite and smectite are superaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that weathing of silicate minerals may be stable kaolinite owing to the continuous water-rock reaction. Geochemical modeling showed that mostly toxic heavy metals may exist larfely in the from of metal-sulfate $(MSO_4\;^2)$and free metal $(M^{2+})$ in nmine water. These metals in the ground and surface water could be formed of $CO_3$ and OH complex ions. The average enrichment indices of water samples are 2.72 of the groundwater, 2.26 of the surface water and 14.15 of the acid mine water, normalizing by surface water composition at the non-mining creek, repectively. Characteristics of some major, minor and rate earth elements (Al/Na, K/Na, V/Ni, Cr/V, Ni/Co, La/Ce, Th/Yb, $La_N/Yb_N$, Co/Th, La/Sc and Sc/Th) in soil and sediment are revealed a narrow range and homogeneous compositions may be explained by acidic to intermediate igneous rocks. And these suggested that sediment source of host granitic gneiss colud be due to rocks of high grade metamorphism originated by sedimentary rocks. Maximum concentrations of environmentally toxic elements in sediment and soil are Fe=53.80 wt.% As=660, Cd=4, Cr=175, Cu=158, Mn=1010, Pb=2933, Sb=4 and Zn=3740 ppm, and extremely high concentrations are found are found in the subsurface soil near the ore dump and precipitates. Normalizing by composition of host granitic gneiss, the average enerichment indices are 3.72 of the sediments, 3.48 of the soils, 10.40 of the precipitates of acid mine drainage and 6.25 of the soils near the main adit. The level of enerichment was very severe in mining drainage sediments, while it was not so great in the soils. mineral composition of soil and sediment near the mining area were partly variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. reddish variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. Reddish brown precipitation mineral in the acid mine drainage identifies by schwertmanite. From the separated mineralgy, soil and sediment are composed of some pyrite, arsenopyite, chalcopyrite, sphalerite, galena, malachite, goethite and various kinds of hydroxied minerals.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.65-85
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• 2023

The use of TBM (Tunnel boring machine) has increased worldwide due to its performance together with the benefit of being safely and environmentally friendly compared to conventional tunneling. In particular, EPB (Earth Pressure Balanced) TBM is widely used because it can be applied to various grounds compared to Open TBM. Also EPB TBM has a simple mechanical structure and advantages in cost, requires less ground area than Slurry TBM. EPB TBM has advantages in soft ground, and more importantly, can extend its applicability by use of appropriate soil conditioning, which improves mechanical and hydrological properties of excavated soil and increases the excavation performance of EPB TBM. Various studies suggested the proper mixing ratio and injection ratio, but almost they are limited to laboratory test under atmospheric pressure such as slump test. Actual field conditions may differ depending on the ground and mechanical condition. In this study, first the amount of used soil conditioning used in the field with various grounds from hard rock to soft ground was estimated through laboratory tests and compared with the estimate in design stage. And also it was compared with the amount used during actual excavation. In addition, experience of soil conditioning for the problems of cutter head clogging and groundwater inrush that occurred during excavation is discussed. Finally, lesson learned for the use of soil conditioning in difficult ground condition such as mixed ground are reviewed.