• The Korean Journal of Ecology
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• 제27권3호
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• pp.133-139
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• 2004

형산강 수계 주변을 대상으로 하여 소형 포유류의 서식현황 및 서식지 선호도를 측정하기 위하여 2003년 1월부터 7월에 걸쳐 조사하였다. 서식이 확인된 소형 포유류는 등줄쥐(Apodemus agrarius), 시궁쥐(Rattus norvegicus), 멧밭쥐(Micromys minutus) 등 3종이었다. 주요 우점종으로는 88개체로 79.20%를 보인 등줄쥐였으며, 다음으로 시궁쥐와 멧밭쥐의 순을 보였다. 소형 포유류의 서식지 선호도는 수계 주변의 토지이용 유형과 경작지, 식생유형, 그리고 제방의 설치 유무와 수심 등 여러 가지 서식지 구조에 따라 다양하게 나타났는데 민가와 삼림에 비하여 경작지에서 특히 논에서의 선호도가 높았으며, 식생 구조별로는 초지의 선호도가 높게 나타났다. 하천제방의 유무도 소형 포유류의 서식에 영향을 미쳤는데 제방이 조성되지 않은 지역이나 자연석 매트 공법으로 이루어진 지역의 경우 소형 포유류의 서식에 부정적인 영향을 미치지 않는 것으로 조사되었으나, 콘크리트 호안제방의 경우 이들의 공간적 분포에 상당한 영향을 미치는 것으로 나타났다. 수계 가장자리의 수심 또한 소형 포유류의 서식에 영향을 미쳤는데 수심이 말아질수록 소형 포유류의 서식밀도는 높게 나타났다.

• 한국환경복원기술학회지
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• 제4권2호
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• pp.62-73
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• 2001

The riparian environments of urban streams in Korea have been disturbed through the channelization for flood control and artificial land use as well as water pollution and flow decrease due to industrialization and urbanization. The flora and vegetation structure were investigated and an implication of stream restoration was discussed for the conservation of biodiversity in the riparian area of the Seunggi stream in Incheon. Naturalized plants and ruderal plants were widely distributed in the riparian area which was disturbed from cultivating, trampling, dumping etc. Submerged and floating hydrophytes were not found in the stream due to channelization and water pollution. Some halophytes were remained in downstream and reservoir after reclamation and embankment. The communities of Humulus japonicus, Panicum dichotomiflorum, Digitaria sanguinalis, Artemisia montana, Amaranthus retroflexus, and Aster pilosus were distributed in the disturbed area of bank slope and floodplain in the stream. As a natural potential vegetation, Phragmites australis in the wet meadow, Typha latifolia, Typha angustifolia, Oenanthe javanica, Persicaria thunbergii, and Penthorum chinense in the marsh, and Salix babylonica and Salix matsudana for. tortuosa in the woodland appeared in the floodplain. The topography in the stream played an important role on the distribution of riparian vegetation in the Seunggi stream. Appropriate methods for conservation and restoration of the riparian ecosystems must be planned on the basis of the actual vegetation in the disturbed urban stream.

• 한국농공학회논문집
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• 제59권4호
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• pp.43-52
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• 2017

This study analyzed pore water pressure, earth pressure and settlement through laboratory model tests in order to suggest the effective remodeling method in the case of reinforcing the upstream and downstream slope of deteriorated reservoirs that has no cores and filters or is not functional. The method of remodeling the upstream slope using dredge soil is first prevent seepage by installing the core, and the leakage water can be rapidly discharged through a filter installed on the downstream slope. Therefore, it is considered a highly efficient method of remodeling that reduces piping phenomena and increasing the storage capacity of the reservoir. The variation of earth pressure without the core and filter was greater than with it, while the change largely showed in the upstream slope, the downstream slope did not show any significant changes. The remodeling method of the downstream slope with the core appeared differently pore water pressure depending on the presence of the vertical and horizontal filters. In the upstream slope, the pore water pressure rises sharply, the base and middle gradually increased, and the downstream slope appeared small. The pore water pressure of embankment with a vertical and horizontal filter will be smaller than without it. The remodeling of deteriorated reservoir that does not have the function of the filter, the vertical filter must be installed in a position that is higher than the expected seepage line by removing portions of the downstream slopes. Since the horizontal filter is an important structure that provides stable drainage during an earthquake or concentrated leak, it is necessary to examine any change in the seepage characteristics depending on the filter intervals via three-dimensional finite element analysis, and it should be connected to the tow-drain to reduce the possibility of the collapse of the reservoir.

• 한국환경복원기술학회지
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• 제5권3호
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• pp.15-22
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• 2002

To analysis of the embanked slope stability using a jointed reinforcement, the internal stability and the external stability have to be satisfied, respectively. But, because the lengths of ready-made steel-grid were limited, the reinforcements must be connecting themselves to the reinforcing. In this study, the mechanical test was carried out to investigate the tensile failure and the pullout failure at the joint parts of them, which was based on the analysis of reinforced slope in field. Through the tensile tests in mid-air for the jointed steel-grid, the deformation behavior was seriously observed as follows : deformation of longitudinal member, plastic deformation of longitudinal member and of crank part. Those effects were due to the confining pressure and overburden pressure of the surrounding ground. The bearing resistance at jointed part of jointed steel-grid was due to the latter only. The maximum tensile forces were higher about 20kN~27kN than ultimate pullout resistance, but, the results of those was almost the same in mid-soil. The failures of steel-grid occurred at welded point both of longitudinal members and transverse members and of jointed parts. The strength of jointed parts itself got pullout force about 20kN, which was about 65% for ultimate pullout force of the longitudinal members N=2. To the stability analysis of reinforced structure including the reinforced slope, the studying of connection effects at jointed part of reinforcement members must be considered. Through the results of them, the stability of reinforced structures should be satisfied.

• 한국수자원학회논문집
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• 제41권6호
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• pp.619-628
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• 2008

하천의 호안은 제방 또는 호안을 유수에 의한 파괴와 침식으로부터 보호하기 위한 구조물로서 과거에는 치수 목적만 갖고 기술자의 주관이나 경험적 판단에 기초해 공법을 선정함으로써 시공한 후 여러 문제점들이 발생하였다. 그러나 현재는 치수뿐만 아니라 환경적 측면이 강조되면서 자연형 호안이 필요하게 되고, 호안종류가 다양해져 호안 공법 선정시 보다 객관적이고 정량적인 해석방법이 필요하게 되었다. 본 연구에서는 호안공법 선정시 기존의 방법에서 문제가 되었던 주관적, 경험적 요소를 최대한 배제하기 위해 안정성, 경제성, 시공성, 친환경성에 대한 세부기준 및 표준화 절차를 제시하고, 최적호안공법 선정에 계층분석과정을 도입하였다. 이로써 실무에서 최적의 호안공법을 선택함에 있어 보다 객관적이고 합리적인 판단의 수단을 제공할 수 있을 것으로 기대된다.

• 환경생물
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• 제37권4호
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• pp.535-544
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• 2019

김 황백화에 대한 원인을 파악하기 위하여 전라북도 김양식장에 2011년부터 2014년까지 양식환경 특성과 황백화 피해 엽체의 형태 및 세포구조를 확인하였다. 연구 결과 금강 하구역에 위치한 개야도에서는 황백화가 확인되지 않았고 새만금방조제 주변의 도청리, 비안도, 무녀도와 선유도에서 황백화가 발생하였다. 김의 황백화 피해는 2011년 11월, 2014년 4월과 11월에 확인되었으며, 황백화 피해 엽체는 엽체 퇴색과 세포 내 액포 비대가 발생하였다. 연구기간 동안 황백화는 DIN과 DIP의 농도가 각각 5 μM와 0.4 μM 이하에서 발생하였다. 용존무기질소(DIN)와 용존무기인(DIP)의 비를 통해 결핍된 용존무기영양염을 확인한 결과 DIN 결핍은 양식 초기, 낮은 DIP 농도는 양식 말기 영향을 미치는 것으로 추정되었다.

• 지질공학
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• 제30권2호
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• pp.131-145
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• 2020

연약지반 상에 도로성토를 시공할 경우 연약지반에는 편재하중이 작용하게 되어 연약지반의 측방유동이나 활동파괴가 종종 발생하게 된다. 본 연구에서는 연약지반에 설치되는 교대말둑기초의 안정성과 말뚝의 거동특성을 파악하는 것이다. 지반의 측방유동으로 인하여 말뚝에 작용하는 수평하중에 대한 기존 연구자들의 연구내용을 파악하고 유한요소해석을 수행하여 교대말뚝기초의 거동특성과 보강효과를 확인하여 측방유동을 받는 교대말뚝기초의 거동을 연구하였다. 압밀도 분석 결과, 압밀 단계에 따라 연약지반 강도증가율에 의해 연약지반의 강도정수인 점착력은 약 1.1~1.8배 증가하였다. 측방유동 검토 결과, 허용수평변위 기준은 3.8 cm를 사용하는 것이 경제적으로나 시공적인 면에서 타당한 것으로 판단되나, 구조물의 중요도 및 지반의 불확실성 등을 고려하여 시공 시 계측을 실시하고 그에 따른 측방유동에 대한 철저한 안전관리가 이루어져야 할 것으로 판단된다.

• 한국농공학회지
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• 제30권4호
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• pp.94-108
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• 1988

The use of geotextile as reinforcing materials in soil structures has become widespread throughout the world. Geotextile reinforcement has been used in retaining walls, roadbed, embankment stabilization and especially reinforcement of soft foundation, and so on, In the past, however, its design and construction have been performed empirically. In this study, laboratory model tests were carried out in order to investigate the effects of geotextile rein- forcement on vertical and horizontal displacement and other characteristics in soft founda- tions. The experiments were executed in eight treatments ;no geotextile between embank - ment and subsoils, and seven geotextiles with different tensile strength. And such factors as the loading conditions, the tensile strength of geotextiles, the ingredient of geotextiles and the elapsed time were investigate in this study. And the analytical method were executed in order to study the stress and behavior of geotextile - reinforced soil structure by the nonlinear elasto - plastic finite element model. The following conclusions were drawn from this study. 1. Geotextile reinforcement reduced the effects of banking loads on subsoils more effectively with the increase of their tensile strength. 2. As the tensile strength of geotextiles was increase, the rate of the initial vertical disp - lacements of loading plate was reduced inverse proportional to loads, Rowever, the effect of loading was reduced when the loads exceed a certain limits, 3. The effect of reinforcement of nonwoven geotextile was 1.5-4.5 times larger than that of the woven geotextile with equivalent tensile strength. 4. The increased bearing capacity and the reduced settlement are proportioned as the tensile strength of geotextile. 5. The settlement at the long time loading were developed almost all, were completed after 10 days and the additional settlement were not developed since then. 6. The nonlinear elasto - plastic finite element method are accurate to predict the stresses and behayior of geotextile - reinforced soil structures.

• 대한공간정보학회지
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• 제18권4호
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• pp.61-69
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• 2010

비탈면 혹은 절성토지의 파괴로 사람과 재산에 심각한 피해를 입히기 때문에 미리 산사태 취약성 분석을 수행하여 개발 혹은 자연재해로부터 위험을 대비하는 것이 필요하다. 기존의 산사태 취약성 분석은 휴리스틱, 통계학적, 결정론적 혹은 확률론적 방법을 통해 이뤄졌다. 그러나, 적은 현장정보 등으로 분석의 신뢰도가 떨어지거나, 전문가의 경험과 지식을 기존 정량적인 해석모델에 반영하기 어려웠다. 본 연구는 산사태 취약성 분석에 대한 전문가 지식과 공간입력자료의 시맨틱을 추출하여 온톨로지 모델을 구축하고, 이를 베이시안 네트워크에 반영하여 확률적인 산사태 모델링을 제안하였다. 기존에 전문가 수작업으로 이뤄지던 베이시안 네트워크의 구조 생성을 온톨로지 모델의 지식추론으로 자동화하고, 현장정보뿐만 아니라 전문가 지식을 모델링에 반영하여 조건부 산사태 발생확률분포를 작성하였다. 이 결과를 GIS에 적용하여 산사태 취약성 지도를 작성하였다. 검증을 위해 충남 홍성일원의 오서산 지역에 적용한 결과 기존 산사태 발생흔적과 86.5% 일치하였다. 본 연구를 통해 일반 사용자도 전문가 도움 없이도 광역적인 산사태 취약성 분석이 가능하리라 기대된다.

• 한국농공학회지
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• 제35권2호
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• pp.43-56
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• 1993

The laboratory tests are performed on how the liquefaction potential of the sea dike structures on the saturated sand or silty sand seabed could be affected due to earthquake before and after construction results are given as follows ; 1. Earthquake damages to sea dike structures consist of lateral deformation, settlement, minor abnormality of the structures and differential settlement of embankments, etc. It is known that severe disasters due to this type of damages are not much documented. Because of its high relative cost of the preventive measures against this type of damages, the designing engineer has much freedom for the play of judgement and ingenuity in the selection of the construction methods, that is, by comparing the cost of the preventive design cost at a design stage to reconstruction cost after minor failure. 2. The factors controlling the liquefaction potential of the hydraulic fill structure are magnitude of earthquake(max. surface velocity), N-value(relative density), gradation, consistency(plastic limit), classification of soil(G & vs), ground water level, compaction method, volumetric shear stress and strain, effective confining stress, and primary consolidation. 3. The probability of liquefaction can be evaluated by the simple method based on SPT and CPT test results or the precise method based on laboratory test results. For sandy or silty sand seabed of the concerned area of this study, it is said that evaluation of liquefaction potential can be done by the one-dimensional analysis using some geotechnical parameters of soil such as Ip, Υt' gradation, N-value, OCR and classification of soils. 4. Based on above mentioned analysis, safety factor of liquefaction potential on the sea bed at the given site is Fs =0.84 when M = 5.23 or amax= 0.12g. With sea dike structures H = 42.5m and 35.5m on the same site Fs= 3.M~2.08 and Fs = 1.74~1.31 are obtained, respectively. local liquefaction can be expected at the toe of the sea dike constructed with hydraulic fill because of lack of constrained effective stress of the area.