• 한국터널지하공간학회 논문집
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• 제18권4호
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• pp.355-364
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• 2016

최근 우리나라 서해안 산업단지의 폐열과 증기의 재활용을 위한 운송관로 수용목적으로 해저 퇴적층 지반에 3.25km의 해저터널이 쉴드 TBM으로 시공 완료되었다. 쉴드 TBM 터널은 지반조건 및 시공요인에 기인한 불확실성으로 인해 장비 침하 등 많은 위험요인을 겪게 되는데 터널 시공 중 쉴드 TBM 장비 침하로 인한 선형이탈이 발생하였으며 원인 분석결과 지지력이 부족한 연약한 점토층 지반조건이 주원인으로 작용한 것으로 검토되었다. 본 연구에서는 지반조건을 고려한 위험요인을 평가하고, 지지력을 고려한 이론식과 TBM 굴진조건 즉, 동적조건을 구현할 수 있는 3차원 수치해석을 통해 장비 침하 및 쉴드 TBM 굴진속도와의 상관관계에 대한 검토를 수행하였다. 연약한 점토층 지반에서 지지력 부족으로 쉴드 TBM 장비 침하가 발생할 수 있으며, 이를 방지하기 위해서는 지반특성에 적합한 최적 굴진속도의 적용이 필요한 것으로 검토되었으며 본 검토 대상구간 지반조건에서는 쉴드 TBM 굴진속도를 35~40 mm/min로 유지하는 경우에 장비 침하를 방지할 수 있는 것으로 검토되었다.

• 식물병연구
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• 제13권2호
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• pp.104-109
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• 2007

양파 연작지 토양의 담수기간에 따른 분홍색뿌리썩음병의 방제효과, 양파의 생육 및 수량을 조사한 결과 토양병원균의 밀도변화는 담수기간이 길수록 균밀도의 감소효과가 뚜렷하여 처리 후 90일에는 무담수에 비해 $1/2{\sim}1/3$ 수준으로 감소하였지만 양파 재배후 균밀도는 담수직후 보다는 전반적으로 증가하는 경향을 보였다. 양파 육묘상 담수처리에 의한 분홍색뿌리썩음병의 방제효과는 담수 60일 이상 처리에서 $93.5{\sim}99.2%$였고, 뿌리이병율도 무담수에 비해 $1/11{\sim}1/18$ 수준으로 크게 감소하였다. 양파 재배포장에서의 발병율 또한 담수 60일 이상 처리에서 5% 미만으로 크게 감소하였다. 양파의 구중과 상품수량은 무담수에 비해 담수처리에서 증가되었으며, 담수기간이 길어질수록 대구의 비율이 늘어나는 경향을 보였다. 이와 같이 양파 분홍색뿌리썩음병이 심하게 발생하고 있는 연작지에 양파를 정식하기 전에 담수처리를 할 경우, 적어도 2년간, 60일 이상 담수처리를 하였을 때 효과적으로 분홍색뿌리썩음병균의 밀도와 병발생을 경감시킬 수 있으며, 정상적인 양파 육묘 및 생육에 의한 구비대로 수량 증수효과가 클 것으로 판단된다.

• 한국토양비료학회지
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• 제48권5호
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• pp.469-476
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• 2015

Button mushroom compost (BMC) was prepared by fermenting the mixture of waste button mushroom bed collected from Boryeong area in South Korea (4): sawdust (8) : pig and fowl manure (1) for 40 days at $30^{\circ}C$. The BMC compromised diverse microorganisms including aerobic bacteria $8.1{\times}10^6cfu\;g^{-1}$, Gram negative bacteria $1.7{\times}10^7cfu\;g^{-1}$, genus Bacillus $6.4{\times}10^6cfu\;g^{-1}$, genus Pseudomonas $1.5{\times}10^4cfu\;g^{-1}$, actinomycetes $1.0{\times}10^4cfu\;g^{-1}$, and fungi $3.5{\times}10^3cfu\;g^{-1}$. BMC was used as a microbial inoculant for estimating the mobilization of heavy metals in soil or plant. When metal solubilization potential of BMC was assessed in a batch experiment, the inoculation of BMC was shown to increase the concentrations of water soluble Co, Pb, Cd, and Zn by 29, 26, 27, and 43% respectively, than those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 17, 15, 18, and 21% respectively in Co, Pb, Cd, and Zn contaminated soils. Moreover, enhanced accumulation of Co, Pb, Cd, and Zn in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the BMC. The apparent results suggested that the BMC could effectively be employed in enhancing phytoextraction from the soils contaminated with heavy metals such as Co, Pb, Cd, and Zn.

• 한국작물학회지
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• 제46권3호
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• pp.165-169
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• 2001

작두콩의 종피는 매우 두껍고 단단하여 발아시 수분흡수가 어렵고 종근의 출현 이후 자엽이 종피로부터 나오는데 많은 시일이 소요된다. 따라서 종피에 기계적인 파상처리를 함으로써 수분흡수를 용이하게 하여 발아율을 높이고자 실시한 시험의 결과를 요약하면 다음과 같다. 1. 작두콩의 무파상 종자는 처리 후 1일이 경과하여도 발아가 전혀 되지 않았으나, 파상처리 종자는 98%의 발아율을 보여 종피의 파상처리는 종자의 발아율을 증가시켰다. 2. 무파상 종자의 수분흡수율은 처리 후 8시간이 경과하여도 10% 이하였으나, 파상처리 종자는 7시간이 지난 후에 종자 건조중의 약 90%수분을 흡수하였으며 8시간 후에는 종자건조중의 150% 이상의 수분을 흡수하였고 종실의 길이와 폭은 약 1.4-l.5배 부풀었다. 3. 파상처리한 종자의 발아율은 고온일수록 높았는데, $25^{\circ}C$와 3$0^{\circ}C$에서 각각 96%와 93%였다. 4. 육묘상에서 상토별 자엽의 출현율은 식양토가 94%로써 모래, 미사 및 콤포스트에 비하여 가장 높았다. 5. 육묘상에서 종피에 파상처리하고 증류수에 침지한 종자가 무파상 종자에 비하여 발아가 조기에 시작되었고, 자엽의 출현율도 파종 9일 후에 92% 이상이었으나 종피파상과 침지처리를 하지 않은 종자는 발아가 늦었고 자엽의 출현율도 67%로써 매우 낮았다.

• 한국작물학회지
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• 제43권4호
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• pp.223-227
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• 1998

The objectives of this study were to find the sprouting condition and to establish the optimum production methods of plug seedlings in yacon (Polymnia sonchifolia Poepp. & Endl.). The sprouting ratio was greatest at $30\pm 1^{\circ}C$ at 20 days after planting. Crowns with single buds were more effective than those with two or more buds for sprouting, which might be due to the apical dominance. Planting the shoots separated from crown after sprouting in the single- and double-layer polyethylene-covered greenhouses reduced seedling period with 25% and 50%, respectively. Planting the shoots after sprouting was more effective than planting the crown buds. Double-layer polyethylene-covered green-house was good for plug seedling production than open field or single-layer polyethylene-covered greenhouse. The bed soils composed of clay loam : compost or sand : compost (1:l=v:v) were more effective to produce plug seedlings than only clay loam, sand or compost. Seedlings could be produced at 30 days after planting in our studies.

• 한국농공학회지
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• 제38권1호
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• pp.79-89
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• 1996

It is expected that the soil hehaviours in the seahed subjected to cyclic wave loads are much different from that on the ground Cyclic shear stresses developed below the ocean bed as a result of a passing wave train may progressively build up pore pressure in certain soils. Such build-up pore pressure may be developed dynamic behaviour such as liquefaction and significant deformation of the seabed. Currently available analytical and testing methods for the seabed subjected to cyclic wave loads are not general. The purpose of the study are to provide a test method in laboratory and to analyse the mechanism of wave-induced stresses and liquefactions potentials of the unsaturated silty marine sand. It is showed that the test set-up made especially for this study delivers exactly oscillatory wave pressures of the form of sine function. Laboratory test results defining the cyclic shear strength of the unsaturated porous medium that is homogenously sedimented. It is understood that the pore water pressure due to induced-waves is not accumulated as the wave number increases but reveals periodical change on the still water surface. The magnitude of the pore water pressure tends to be attenuated radically with a certain time lag under the action of both high and low waves as depth increases.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.517-524
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• 2004

The leading cause of bridge failures is scouring bed material from around bridge foundations. Many advanced countries such as U.S.A., U.K., the Netherlands and New Zealand have developed and revised their own bridge scour manuals fit for their field conditions. In Korea, researches for reducing bridge failures during floods have concentrated on analysis, laboratory test and countermeasure of bridge scour during the last ten years. however no comprehensive manual for evaluating bridge scour and for identifying the conditions of bridge foundations has been provided yet. In this study, a new bridge scour manual is developed for the accurate evaluation of bridge scour, which reflects domestic field conditions with various streambed materials. The SRICOS method and the Erodibility Index Method are suggested for fine-grained soils and weathered rocks, respectively. In addition, bridge scour analysis algorithms are developed for field engineers to estimate bridge scour depth and to evaluate the susceptibility of bridge scour with ease.

• 한국약용작물학회지
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• 제6권4호
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• pp.251-257
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• 1998

우리나라 황칠나무의 자생지인 전남 완도지방에서 황칠나무의 재배시 삽목번식법을 체계적으로 확립 하고자 시험을 실시한 결과는 다음과 같다. 1. 삽목의 종류로는 숙지삽과 녹지삽이 가능하였으며, 숙지삽 보다는 녹지삽이 캘러스형성이 양호하고 발근율이 높은 경향이었다. 삽목시기는 숙지삽은 2월${\sim}$3월 중순경 실시하고, 녹지삽은 2월${\sim}$3월경 실시하는 것이 발근율이 높아 적당한 시기로 판단된다. 2. 황칠나무의 경삽시 삽식형태는 관삽(normalcutting)보다는 단자삽(earthen-ball cutting) 이 캘러스 형성율이 높고 발근이 양호하였다. 3. 상토는 통기성과 보수성이 양호한 사양토가 발근에 효과적이었으며, 경제성이 있을 것으로 생각되어 적당한 상토로 생각된다. 4. 식물생장조절제는 IBA(indole butyric acid)를 100ppm처리할 경우 캘러스 형성율이 높고 발근이 촉진되는 경향이었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1058-1064
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• 2004

As one of reinforcing methods for soft roadbed, the problems that mud-pumping and settlement occurred by soft roadbed, were investigated, evaluated and analyzed through installing relatively economical and efficient geosynthetics on the selected track-bed for testing. Mock-heang to Dong-ryang on the filed resting sections in the Chung-buk lines were selected as investigating the state of track and prepared field after selecting three of 1,700 spots which often make mud-pumping and requiting maintenance for that. Long curved line radiuses(R) of Mock-heang to Dong-ryang are 500m that were installed with 4 types of geosynthetics layers and one ballast layer. Installed testing cross-section is 200m totally with 40 m between places. Strength or prepared roadbed was measured to investigate the state of roadbed and track with constructing(installing) field testing sections and physical properties of roadbed soils were evaluated and analyzed. Also, mud-pumping, settlement of elastic or plastic sleeper, failure or track, wheel-loads, transverse and earth pressures were measured after installing field testing sections.

• Geomechanics and Engineering
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• 제29권6호
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• pp.645-655
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• 2022

Granular columns have recently found widespread use in underground construction. The behaviour of granular columns under vertical loads has been extensively studied, specifically in relation to vertical load capacity obtained by bulging of the column body, including the behaviour after encasement of material. Determining the shear strength of loose soils reinforced with granular columns has received less attention. After the observations of lateral deformation near the toe of the embankment, attempts have been made to strengthen the lateral strength of granular columns. The purpose of this research is to look into the effects of different encasement conditions on the lateral load capacity of granular columns. This was accomplished by three-dimensional finite element analysis with FEM software. Various normal pressures and two different encasement configurations, namely single layer encasement and double layer encasement, with differing tensile strengths, were used in this study to determine their effect on lateral resistance. The failure envelope for a single column planted in loose sand was used to analyse the findings for three different granular column diameters, as well as the impact of different encasement conditions. According to the findings, the inclusion of a Granular Column enhanced the shear strength and overall stiffness of the loose sand bed, and the encasement of the Granular Column helped in deriving higher lateral resistance.