• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.117-128
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• 2014

Generally, when constructing a tunnel close to existing structures, the tunnel must be built at a constant distance from the structures that is more than width of tunnel to minimize the impact of interference between an existing structures and new tunnel. Spacing of these closed tunnels should be designed considering soil state, size of tunnel and reinforcement method. Particularly when the ground is soft, a care should be taken with the tunnel plans because the closer the tunnel is to the existing structures, the greater the deformation becomes. As methods of reviewing the effect of cavities on the stability of a tunnel, field measurement, numerical analysis and scaled model test can be considered. In the methods, the scaled model test can reproduce the engineering characteristics of a rock in a field condition and the shape of structures using the scale factor even not all conditions cannot be considered. In this study, when construction of a tunnel close to existing structures, the method and considering factors of the scaled model test were studied to predict the actual tunnel behavior in planning stage. Furthermore, model test results were compared with the numerical analysis results for verifying the proposed model test procedure. Also, practical results were derived to verify the stability of a tunnel vis-a-vis cavities through the scaled model test, which assumed spacing distances of 0.25 D, 0.50 D, and 1.00 D between the cavities and tunnel as well as the network state distribution. The spacing distances of 1.0 D is evaluated as the critical distance by the results of model test and numerical analysis.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.565-583
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• 2020

In recent years, various social issues related to the natural radioactive elements detected in household goods and building materials are addressed, and should be solved promptly. In Korea, for more than 20 years, the Ministry of Environment has investigated the natural radioactive materials such as heavy metals, uranium, and radon in soil or groundwater. The origins of natural radioactive materials in them may have a close correlation with the geological factors including classification of rocks, petrogenetic origins, and deformation characteristics, but the exact geological correlations are not clarified because of the absence of the government policy preserved in the basement rocks, soils as well as groundwater in fault-related reservoirs. This study aims to perform a research on the correlation between the petrogeneses of the Phanerozoic plutonic rocks and natural radioactive concentrations in rocks (radon, uranium, thorium, potassium etc.) in Korea. Among the Phanerozoic plutonic rocks, alkaline plutonic rocks (syenite, monzonite and monzodiorite and alkali granite) show high U and Th concentrations by high solubilities of U, Th, Zr, REE, and Nb until the most extreme stages of magmatic fractionation (viz. crystal fractionation) due to high magma temperature and high alkalinity tendency. The highly fractionated high-K calalkaline and peraluminous granitic rocks (leucogranite, two-mica granite and leucocratic pegmatite are also U and Th concentrations compared with other less or medium fractionated granitic rocks (diorite, granodiorite and granite). The alkaline plutonic rocks are associated with intracontinental rifting and extensional environment after crustal thickening by collisional and subductional processes. In contrast, the dominant calc-alkaline granitic rocks in Korea are related to the arc environment of the subduction zone. In summary, the trends of the U, Th and K concentration from the Phanerozoic plutonic rocks in Korea are closely linked to the petrogenesis of the rocks in tectonic environment. The preliminary data for gamma-spectrometric mesurments of natural radionuclide contents (²²⁶Ra, ²³²Th and ⁴⁰K) in the Phanerozoic plutonic rocks show high values in the alkaline and highly fractionated granitic rocks.

• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.11-19
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• 2011

This research gives weight to establish practical improvement based on analysis of the landscape ecological character and value to realize the importance of small wetland and stream in cultivated areas functioning as a residual landscape element in rural landscape and to deal with ecological depression effectively. The results of summary are as follows. 1) The results of landscape ecological character analysis of wetlands biotop in total of 7 sites, for example, size of surface in site 5 was widely formed about $10,600m^2$, which was assessed satisfactory in terms of slope of waterfront, width of hedgerow, vegetation condition of composition and so on. Also, The number of flexibility showed 2 in site 8-1, the highest, and morphological diversity showed 1.47, the highest. 2) The results of problem analysis of wetland biotop, most of wetlands are analyzed that the width of hedgerow was below 1m. Also, the 4 wetlands in site 8 are appeared that hard to live slope vegetation in there because of slope of waterfronts are above $45^{\circ}$. 3) The results of landscape ecological character analysis of stream in total of 6 sites, for example, width of waterfront in site 4 showed 55m, the widest, and investigated consist of natural ingredients such as soil, rock, gravel. However, width of waterfront in site 2-2 showed 4m, the narrowest, and inclined angle of slope was formed a right angle. 4) The results of problem analysis of stream, width of waterfront hedgerow in site 2-1 showed about 5m, which was very narrower than width of waterfront, and toxic chemicals discharged from near cultivated area without any filtering. Also, all areas of site 2-2 was formed concrete, and was assessed dissatisfactory in terms of capacity of nature purification, flood control, habitat living space because of straight stream. 5) Based on the result above landscape ecological character and problem analysis, main improvement guidelines are set in terms of shape, vegetation, topography in case of wetlands, and which are set in terms of vertical, horizontal structure in case of stream.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.1
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• pp.4592-4598
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• 1978

The purpose of this research is to find out mathemetically an economical intake water depth in the design of head works through the derivation of some formulas. For the performance of the purpose the following formulas were found out for the design intake water depth in each flow type of intake sluice, such as overflow type and orifice type. (1) The conditional equations of !he economical intake water depth in .case that weir body is placed on permeable soil layer ; (a) in the overflow type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }+ { 1} over {2 } { Cp}_{3 }L(0.67 SQRT { q} -0.61) { ( { d}_{0 }+ { h}_{1 }+ { h}_{0 } )}^{- { 1} over {2 } }- { { { 3Q}_{1 } { p}_{5 } { h}_{1 } }^{- { 5} over {2 } } } over { { 2m}_{1 }(1-s) SQRT { 2gs} }+[ LEFT { b+ { 4C TIMES { 0.61}^{2 } } over {3(r-1) }+z( { d}_{0 }+ { h}_{0 } ) RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L+ { dcp}_{3 }L+ { nkp}_{5 }+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ] =0}}}} (b) in the orifice type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }+ { 1} over {2 } C { p}_{3 }L(0.67 SQRT { q} -0.61)}}}} {{{{ { ({d }_{0 }+ { h}_{1 }+ { h}_{0 } )}^{ - { 1} over {2 } }- { { 3Q}_{1 } { p}_{ 6} { { h}_{1 } }^{- { 5} over {2 } } } over { { 2m}_{ 2}m' SQRT { 2gs} }+[ LEFT { b+ { 4C TIMES { 0.61}^{2 } } over {3(r-1) }+z( { d}_{0 }+ { h}_{0 } ) RIGHT } { p}_{1 }L }}}} {{{{+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 } L+dC { p}_{4 }L+(2 { z}_{0 }+m )(1-s) { L}_{d } { p}_{7 }]=0 }}}} where, z=outer slope of weir body (value of cotangent), h1=intake water depth (m), L=total length of weir (m), C=Bligh's creep ratio, q=flood discharge overflowing weir crest per unit length of weir (m3/sec/m), d0=average height to intake sill elevation in weir (m), h0=freeboard of weir (m), Q1=design irrigation requirements (m3/sec), m1=coefficient of head loss (0.9∼0.95) s=(h1-h2)/h1, h2=flow water depth outside intake sluice gate (m), b=width of weir crest (m), r=specific weight of weir materials, d=depth of cutting along seepage length under the weir (m), n=number of side contraction, k=coefficient of side contraction loss (0.02∼0.04), m2=coefficient of discharge (0.7∼0.9) m'=h0/h1, h0=open height of gate (m), p1 and p4=unit price of weir body and of excavation of weir site, respectively (won/㎥), p2 and p3=unit price of construction form and of revetment for protection of downstream riverbed, respectively (won/㎡), p5 and p6=average cost per unit width of intake sluice including cost of intake canal having the same one as width of the sluice in case of overflow type and orifice type respectively (won/m), zo : inner slope of section area in intake canal from its beginning point to its changing point to ordinary flow section, m: coefficient concerning the mean width of intak canal site,a : freeboard of intake canal. (2) The conditional equations of the economical intake water depth in case that weir body is built on the foundation of rock bed ; (a) in the overflow type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }- { { { 3Q}_{1 } { p}_{5 } { h}_{1 } }^{- {5 } over {2 } } } over { { 2m}_{1 }(1-s) SQRT { 2gs} }+[ LEFT { b+z( { d}_{0 }+ { h}_{0 } )RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L+ { nkp}_{5 }}}}} {{{{+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ]=0 }}}} (b) in the orifice type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }- { { { 3Q}_{1 } { p}_{6 } { h}_{1 } }^{- {5 } over {2 } } } over { { 2m}_{2 }m' SQRT { 2gs} }+[ LEFT { b+z( { d}_{0 }+ { h}_{0 } )RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L}}}} {{{{+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ]=0}}}} The construction cost of weir cut-off and revetment on outside slope of leeve, and the damages suffered from inundation in upstream area were not included in the process of deriving the above conditional equations, but it is true that magnitude of intake water depth influences somewhat on the cost and damages. Therefore, in applying the above equations the fact that should not be over looked is that the design value of intake water depth to be adopted should not be more largely determined than the value of h1 satisfying the above formulas.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.69-78
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• 2010

In order to investigate the degree of household dust contamination, 48 samples of household dust (24 from urban area and 24 from rural area) in Daegu city were collected in vacuum cleaner during January to February 2009. Samples were sieved below 100 ${\mu}m$, and 14 elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, Zn) were analyzed using ICP after acid extraction. Results obtained from the source assessment of trace elements using enrichment factor showed that Ca, Fe, K, Mg, Mn, Na, and V were influenced by natural sources such as weathered rock and resuspended soil, while Cd, Cr, Cu, Ni, Pb and Zn were influenced by anthropogenic sources such as fuel combustion and waste incineration. Concentrations were remarkably higher in components from natural sources than in components from urban anthropogenic sources. Household dust in urban area was more affected by anthropogenic sources compared with that of rural area. Pollution index of heavy metals revealed that urban area was 1.8 times more contaminated with heavy metal components than rural area. The correlation analysis among trace elements indicated that components were correlated with natural sources-natural sources (Al-Mg, Al-Mn, Fe-Mn) and natural sources-anthropogenic sources (Al-V, Fe-Cr, V-Mn) in both urban area and rural area. Trace element components of rural area were more correlated than those of urban area. Houses that use oil for heating fuel had relatively higher contents of heavy metals rather than those using gas or electricity for heating fuel. Houses with children also had higher contents of heavy metals. In addition, the age of houses was found to influence the heavy metal levels in household dusts, with older houses (>10years) having higher concentrations than newer houses (<10years) and houses located near the major road (<10 m) were found to have relatively higher heavy metal levels in household dust.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.547-561
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• 2005

General characteristics of groundwater contamination by As were reviewed with several recent researches, and its occurrence in groundwater of Korea was investigated based on a ffw previous studies and a groundwater quality survey in Nonsan and Geumsan areas. In Bangladesh, which has been known as the most serious arsenic calamity country, about $28\%$ of the shallow groundwaters exceeded the Bangladesh drinking water standard, $50{\mu}g/L$, and it was estimated that about 28 million people were exposed to concentrations greater than the standard. Groundwater was characterized by circum-neutral pH with a moderate to strong reducing conditions. Low concentrations of $SO_4^{2-}$ and $NO_3^-$, and high contents of dissolved organic carbon (DOC) and $NH_4^+$ were typical chemical characteristics. Total As concentrations were enriched in the Holocene alluvial aquifers with a dominance of As(III) species. It was generally agreed that reductive dissolution of Fe oxyhydroxides was the main mechanism for the release of As into groundwater coupling with the presence of organic matters and microbial activities as principal factors. A new model has also been suggested to explain how arsenic can naturally contaminate groundwaters far from the ultimate source with transport of As by active tectonic uplift and glaciatiion during Pleistocene, chemical weathering and deposition, and microbial reaction processes. In Korea, it has not been reported to be so serious As contamination, and from the national groundwater quality monitoring survey, only about $1\%$ of grounwaters have concentrations higher than $10{\mu}g/:L.$ However, it was revealed that $19.3\%$ of mineral waters, and $7\%$ of tube-well waters from Nonsan and Geumsan areas contained As concentrations above $10{\mu}g/:L.$. Also, percentages exceeding this value during detailed groundwater quality surveys were $36\%\;and\;22\%$ from Jeonnam and Ulsan areas, respectively, indicating As enrichment possibly by geological factors and local mineralization. Further systematic researches need to proceed in areas potential to As contamination such as mineralized, metasedimentary rock-based, alluvial, and acid sulfate soil areas. Prior to that, it is required to understand various geochemical and microbial processes, and groundwater flow characteristics affecting the behavior of As.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.3
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• pp.45-76
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• 2000

The purposes of this study were to investigate and understand the present status of various types of "deserts", such as sand desert, gravel desert, rock desert, earth desert, salt desert, desert, rocky desert, gobi desert, sandy desert, clay desert, etc., and the general countermeasures for the combating "desertification" "desertization", and to develop the technologies on the revegetation and restoration for the combating desertification in China. The methods of this study were mainly composed of field surveys on the several experimental sites and research institutes related to combating desertification in China, and examinations on the various technologies for the combating desertification at the Daxing Experimental Station of Beijing Forestry University. The conclusion from this study may be summarized as follows; 1. Status and tendency of desertification in China : China is one of the countries seriously threatened by desertification. Desertification affected areas in China are mainly distributed in arid, semi-arid and dry sub-humid areas in China, covering the most regions of the Northeast China (eastern region of Inner-Mongolia), the northern part of the North China (middle and western region of Inner-Mongolia, Shaanxi, Ningsha, Gansu) and the western part of the Northwest China (Xinzang, Qinghai, Xizang). The total area affected by desertification in China is approximately 2.622 million $km^2$. It covers 27.3% of the total territory of China. Until recently, it is estimated that the annual spreading ratio of desertification in China is 2,460 $km^2$. Therefore, desertification is mostly serious problems facing to the Chinese people. 2. The causes and environmental effect of desertification : The desertification in China is mainly caused by compound factors, including natural condition and human activities. In China, the desertification is started by the decrease of precipitation, continuous dry and drought, strong wind, wind and water erosion, land degradation and loss of natural vegetation caused by climate variation, and accelerated by the human activities, such as over-cultivating, over-grazing, over-cutting of woods, irrational use of water resources. Because desertification has affected the geographical features, soil nutrients contents, salinity, vegetation coverage and the functions of ecosystem, the environmental deteriorations in the desertification affected areas are very seriously. 3. The fundamental strategies of combating desertification in China are the increase of education and awareness of people through various mass media, the revision of laws to guarantee operation of Desertification Combating Law and to improve many relating laws and regulations, the application of advanced technologies and training of experts, the establishment of discriminative policies, and increasing arrangement of budget-investment, and so on. China, as a signed country in UNCCD, has made efforts for the combating desertification. Korea is also signed country in UNCCD, so we should play an important role in the desertification combating projects of China for the northest asia and global environmental conservation as well as environmental conservation of Korea.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.129-140
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• 1998

In this study two sites were selected to investigate groundwater contamination and spatial relationship between pollution level and its source. One is the Asan area, agricultural district where pollution sources are scattered. The other is the Gurogu area of Seoul city, industrial district where industrial complex and residential areas are located. Groundwater samples collected from these districts were analysis for chemical constituents. The attribute value files of the chemical constituents of groundwater and the spatial layers have been constructed and the pollution properties have been investigated to find out spatial relationships between the groundwater constituents and pollution sources using CIS. Relatively high contents of Si and HCO$_3$ in groundwater from the Asan area reflect the effect of water-rock interaction, whereas high contents of Cl, NO$_3$, SO$_4$and Ca in groundwater from the Gurogu area are due to the pollution of various sources. Pollution over the critical level of Korean Dinking Water Standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. There is pollution of NO$_3$, Cl, Fe, Mn, SO$_4$and Zn in groundwater from the Gurogu area, and that of NO$_3$, SO$_4$and Zn in groundwater from the Asan area. Principal pollution in both areas is NO$_3$contamination. Deep groundwater from the Asan area is not contaminated with NO$_3$except for one site and most of shallow groundwater near the potential point sources such as factory and stock farm is contaminated seriously. Groundwater from the Gurogu area has been already polluted seriously considering the fact of contamination of deep groundwater. This study reports a spatial relationship between the pollution level and pollution source using GIS.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.524-540
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• 2005

This study has focused on the amount of evaporites and geochemical characteritics of evaporites from the acid mine drainage and on the variation of constituents in acid mine drainage during evaporation. The various colors of evaporites are frequently observed at the rock surfaces contacting acid mine drainage. In order to produce evaporites in the laboratory, acid mine drainages were sampled from the abandoned mine areas (GTa, GTb, GH and GB) and air-dried at room temperature. During the evaporation of acid mine drainages, TDS, EC values and the concentrations of major and minor ions increased, whereas ER and DO values decreased with time. The concentration of Fe increased gradually with evaporation time in the GTb and GB, whereas GH founded in one day but rapidly not detected in the other day after due to removal of Fe by formation-precipitation of amorphous Fe hydroxide. The amounts of the evaporites were produced in amounts of 4 g (GTa), 5 g (GB), 15 g (GH), and 24 g (GTb) from 4 liter of acid mine drainage after 80 days of the evaporation, respectively. In linear analysis from the products with the parameters which are the EC, TDS, salinity, ER, DO and pH contents in field, the determination coefficients were 0.98, 0.99, 0.98, 0.88, 0.89, and 0.25 respectively. If we measure the parameters in field, it would be easy to estimate the amount of evaporites in acid mine drainage. Gypsum and epsomite were identified in all of the evaporites by x-ray powder diffraction studies. Evaporite (GTb) was heated at 52, 65, 70, 95, 150, 250, and 350oC for one hour in electrical furnaces. Gypsum, $CaSO_4\cdot1/2H_2O$ and kieserite were identified in the heated evaporite by XRD. With increased heating temperature, the intensity of the peak at $7.66/AA$ (diagnostic peak of gypsum), the peak at 5.59A ($CaSO_4{\cdot}1/2H_2O)$ and the peak at $4.83{\AA}$ (kieserite) decreased in x-ray diffraction due to dehydration. In the SEM and EDS analysis for the evaporite, gypsum of well-crystallized, radiating cluster of fibrous, acicular, and columnar shapes were observed in all samples. Ca was not detected in the EDS analysis of the flower structures of GTb. Because of that, the evaporite with flower structures is thought to be eposmite.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.387-394
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• 2012

The study was conducted to develop an effective forest resources use models for an alternate use of abandoned quarry by an attitude survey. According to the result of survey, a pessimistic view due to dust, noise pollution, and forest damage was 5% higher than an affirmative view by economic benefits from the development of quarry. The 42% of the respondents preferred the alternate use of abandoned quarry and the 25% of the respondents wanted an art and cultural space. The optimum size of alternate use was 5-10 ha (43%) with the requirement of nearby residents (32%). According to the SWOT analysis for abandoned quarry, the strength factors were an effective use of land, the content development of modern industrial inheritance + cultural and art fusion, attraction for nearby city and visitors, a harmony of beauty landscape and clean environment, and a sustainable increase of domestic and foreign visitors with the 5-day-work week. The opportunity factors were the improvement of traffic networks through KTX and local highway, the creation of the new growth engines with the establishment of artistic creation belts, the providing of unique cultural and art space through grafting of tour and education, the creation of local income through stone processed goods, and the vitalization of local development through eco-city. The weakness factors were a psychological remoteness and backwardness, and the weakness of staying tour infra. The threat factors were a poor financial support for sustainable development in nearby quarry and a modify of legal and institutional system for the alternated use of abandoned quarry. The developed restoration models for the alternate use in abandoned quarry are classified to a sculpture park, a waterfall and lake park, a rock-climbing, a sports park + forest park, a native botanical garden, a culture and art park, a complex park, a water storage site, a water storage site to extinguish forest fire, a geriatric hospital, an agricultural facility, and a school site types etc. The results suggest that the alternate use in the abandoned soil and stone quarry is needed to establish facility use models with consideration of user's preference.