물 유거(Run-off)에 따른 토양유실량을 자동정량하고자 ISCO 6712 수질환경 종합측정장치를 이용하여 토양유실량 추정장치를 고안하였고, 이 장치를 통해 실시간으로 유실되는 토양량을 추정할 수 있었다. 토양유실량 추정장치는 ISCO 6712 장치에 수위계(ISCO 730), 우량계(ISCO 674) 그리고 흙탕물을 받는 저수조 내에 층위 별로 흙탕물을 자동으로 채취할 수 있는 시설을 추가하였다. 1 × 5 m2 크기, 경사 15 %의 라이시미터(lysimeter) 내 석비레(Saprolite) 토양에 옥수수를 심어 실험한 결과 2017년 1회 강우량 161.3 ㎜의 강우사상에서는 실측 토양유실량의 85.1%, 82.6 ㎜ 강우사상에서는 101.7 %의 토양량을 추정하였다.

In this study, the conventional cylinder-shaped lower bar on the canvas was modified and its performance was tested to improve the opening force of the stow net on anchor. The improved new lower bar used in the test is consisted of 13 flat bars with a length of 1.8 m, a width of 0.075 m and a thickness of 4 mm, and a pipe with a length of 2.0 m and a diameter of 50 mm. A stow net with the improved lower bar and a stow net with an existing lower bar were installed underwater and their trajectories for 21 hours were examined. To confirm their trajectories, GPS loggers were attached to the buoys on the left and right canvases and the buoy of the hauling rope. As a result of the test, the rotation of the gear with the improved bar was smoother than that with the existing bar. As a result of comparing the changes in the interval of the buoys attached to the canvas after the low and high tide, the buoy spacing of the gear with the improved bar is wider than that of the conventional gear; moreover, the larger the interval, the smoother the rotation of the fishing gear was. Therefore, it is considered that using the improved lower bar can enhance the performance of the stow net.

PURPOSES : The frequency and severity of natural disasters such as torrential rain or typhoons have become increasingly significant worldwide. Events such as summer typhoons and localized torrential downpour can cause severe damages to a residential area and road networks, resulting in serious harm to the daily lives of people, especially in rural areas by isolating residents from road networks. An immediate and emergency repair technology for the collapsed road networks is urgently needed. This study introduces a new technology to repair road bases or slopes. METHODS: The development of new technology for emergency and permanent repair consists of first, packing of cement paste-coated gravel, second, combining appropriate equipment, and third, conducting a field applicability test. In this research, the compressive strength of cement pastecoated gravel, gravel-netting concrete properties, and packing efficiency were determined, and a full scale field mock-up test was carried out. RESULTS : The compressive strength of the cement paste-coated gravel concrete satisfied the required limit for road base of 5 MPa after 7 days. With appropriate netting materials and packing size, gravel-netting concrete was successful up to a slope of 1:1.5. The full scale field mockup test showed efficiency in the field and penetration resistance performance. CONCLUSIONS: The new technology of emergency and permanent repair for damaged road bases and slopes, introduced in this study, showed satisfactory performance. The technology is expected to be applied in the field when construction procedures and quality specifications are made.

최근 호우 및 산사태 등 자연재해로 인한 도로유실 피해가 증가하고 있으며, 특히 지역특성상 산림이 많이 분포된 지역은 피해가 큰 실정이다. 또한, 유실부 긴급복구 방법은 일시적 교통개방이며, 지속된 교통개방이 어려운 상태이다. 이에 본 연구에서는 도로유실 긴급복구를 위한 연구의 일환으로 골재망을 활용한 다공질 콘크리트 긴급복구 공법의 장비조합을 제안하고자 하였으며, 최소한의 장비로 현장배합 및 도로유실 긴급복구에 활용하고자 한다. 장비, 재료 운반 및 하차수단으로 카고크레인 및 일반 적재트럭으로 2식의 차량을 제안하며, 운반 구성은 현장배합용으로 시멘트, 몰탈믹서, 1㎥물통과 유실부 복구를 위한 골재망, 시멘트페이스트 적재 박스와 골재망 적치는 카고크레인으로 대처하며, 현장지반정리용 0.2B/H, 다공질콘크리트 일부다짐용 콤펙터를 활용하였다. 그림1 및 그림2는 제안한 2식의 차량으로 활용되는 계획을 각각 나타내며, 그림3은 제시한 장비조합의 긴급복구 계획을 나타내고 있다. 도로유실 긴급복구 골재망 활용 다공질 콘크리트의 현장배합 및 시공을 위한 장비조합을 제시하고자 하였으며, 이에 따른 결과는 다음과 같다. 1) 제시한 장비조합은 대형 중장비가 아닌 중 · 소형 장비, 재료로써 운반 및 사용이 용이하며, 신속하고 항구적인 골재망 활용 다공질콘크리트 긴급복구 공법에 적합하다 판단된다. 2) 제시한 장비조합은 Mock-up시험 등을 통한 검증필요가 예상되며, 유실위치 및 규모에 따른 추가 장비구성 및 시공방법 변경에 대한 추가적인 계획이 필요할 것으로 사료된다.

This study aims to investigate effects of the length of the buoy and sand bag line on the loss of webfoot octopus pot. A numerical modeling and simulation was carried out to analyze the process that the pot gear affected by wave using the mass spring model. Through the simulation, tensions of sand bag line under various condition were investigated by length of buoy and sand bag line. The drag force and coefficient k of an artificial shell used in the webfoot octopus pot was obtained from an experiment in a circular water channel, and the coefficient k was applied to the simulation. To verify the accuracy of the simulation model, a simple test was conducted into measuring a rope tension of a hanging shell under flow. Then, the test result was compared with the simulation. The lengths of the buoy line in the simulation were 1.12, 1.41, 1.80, 2.23, 2.69, and 3.17 times of water depth. The lengths of sand bag line were 10, 20, 30, and 40 meters, and conditions of water depth were 8, 15, 22 meters. 4 meter height and 8 second period of wave were applied to all simulations. As a results, the tension of the sand bag line was decreased as the buoy and sand bag line were increased. The minimum tension of the sand bag line was appeared in conditions that the length of the buoy line is twice of water depth and the sand bag line length is over 40 meters (except in case of depth 8 meters.).

The Fishing gear loss has been repeated every year in the West Sea; however, there has been no solution. So fisher men have undergone economic loss every year. Thus it is required to reduce the loss of fishing gear. In this study to find out the reason that the fishing gear is lost in the Sea, 10 years data of wave and current for 6 locations in the West Sea were investigated and a numerical modelling were conducted into the behaviour of a gillnet in wave and current. The fishing gear was modelled with the mass spring model. As a result, it came out into the open that the location where fishing gear loss occurred most frequently was Choongnam province. The height of the maximum significant wave in this province was 6.7 m and the period of that was 4.4 second. The maximum current speed was 0.7 m/s. As a result of simulation with these data, it was revealed that the buoy is one of the reasons to decrease the holding power of the gillnet. For example, the tension of anchor rope was decreased to 50% while the drag coefficient or volume of buoy was decreased to 25%. So it is predicted that an improvement of the buoy contributes to the reduction of the gillnet loss.

PURPOSES: As a part of our research into repair techniques for roads that have collapsed as a result of a natural disaster, this study set out to find the optimum mix proportion for gravels to be used to restore a damaged area. METHODS: This study considered flow and strength-development characteristics. The experimental variables were the W/C ratio, the usage of the admixture, the types of cement, and the quantity of fine aggregate over three different experimental stages. The compressive strength was measured at 12 hours, one day, three days, and seven days. RESULTS : The flow varied with the amount of fine aggregate and the use of a high-range water-reducing (HRWR) admixture. The compressive strength also varied with respect to the type of cement and the W/C ratios. The strength satisfied the expected requirement of 21 MPa after one day, provided the mix proportion was appropriate. CONCLUSIONS: A gravel-filling high-flow cement-based mortar exhibited strength and consistency with a W/C ratio in the range of 0.40 to 0.45, assuming the use of HRWR at 0.5 to 0.7% and a fine aggregate/cement ratio of 1.0 to 1.5.

Sediment basin that is typical facility installed for development business to prevent soil erosion has low removal efficiency and therefore, it causes complaints from the residents and has a bad effect on ecosystem.Thus there is a limit to control soil erosion using the existing design methods of sediment basin, so the purposes of this study is providing suitable design factors for sediment basin with regarding soil characteristic of development areas and analysing sedimentation characteristic by inflow concentration changes.The results, for analyzing the sedimentation characteristic by soil concentrations within approximately 2,000 ~ 20,000 mg/L of initial SS concentration, indicated similar sedimentation trends for same soil in the supernatant regardless of initial concentrations. However, for different soil characteristic (percent finer), there are different results in sedimentation rate and concentrations of the supernatant.Thus it is recommended that sediment basin to prevent soil erosion during construction should be designed based on retention time derived from soil sedimentation experiments regardless of inlet concentration. In addition, installing the soil erosion prevention facility at the back to satisfy effluent water quality should be considered to minimize soil erosion effectively.

본 연구는 경사지 밭에서의 토양유실량 저감을 위해 실트펜스와 식생밭두렁의 적용 가능성을 평가하기 위한 현장실험 연구로, 이를 위해 전라북도 익산시 금마면에 시험포장을 설치하고 포장실험을 수행하였다. 시험포장은 표준시험포 크기 (5 m × 22 m), 경사 9%의 시험구 3개소와 정방형 크기(15 m × 15 m), 경사 6%의 시험구 2개소로 구성되어 있으며, 포장에서의 강우량을 측정하기 위해 자기우량계를 설치하였고, 각 시험구의 말단에는 유출량을 측정하기 위한 플륨 및 수위계를 설치하여 모니터링 하였다. 강우시 유출수에 의해 토양이 유실되며 토양 입자에 흡착되어 있는 오염물질도 같이 유출되는데 이러한 유출수의 오염 부하량을 산정하여 토양유실량을 평가하였다. 시간변화에 따라 오염 부하량 저감효과를 분석한 결과 대조구 시험포를 기준으로 실트펜스에서 SS 50.1%가 저감되었고 SS 항목이 저감되었다는 것은 유사가 저감되어 토양유실을 저감시킨 것을 나타낸다. 향후 추가적인 연구를 통해 경사지밭 토양유실량 저감효과를 평가하고 제어대책을 개발하게 되면 밭에서의 토양유실을 최소화시켜 수질개선에 기여할 것으로 사료된다.

본 연구는 우분액비의 시용이 경사도를 달리한 사료용 옥수수 재배지에서 옥수수의 생산성 및 유거수 중의 N의 유실에 미치는 영향을 조사하기 위하여, 건국대학교 축산대학 사료작물 시험포 내 설치된 Erosion apparatuses (가로 0.33 m, 세로 3 m, 깊이 0.4 m)를 이용하여 수행하였다. 시험구의 경사도는 0%, 8.75%, 17.50%로 하였으며, 우분액비는 6개월 이상 부숙된 것으로 질소 기준 200 kg/ha 시용하였다. 옥수수의

본 연구는 사료작물 재배지에 가축분뇨를 시용한 사료작물 재배지에서 초지식생대를 설치에 따른 -P와 토양 유실 저감 효과를 구명하기 위하여 수행되었다. 본 시험은 국립축산과학원 초지사료과 시험포장(천안)에서 경사가 약 10%에서 인 자연 경사지를 이용하여 2007년부터 2009년까지 3년간 수행하였다. 가축분뇨 시용은 화학비료, 우분퇴비 및 돈분퇴비를 시용하였으며, 초지식생대의 길이는 5 m, 10 m 및 15 m의 길이로 설치하였다. 초지식생대 길이에

railroad has a benefit of the mass transportation of a passenger and cargo, but just a time of accident could cause a huge loss of a human life and property. Especially, a typhoon and a localized torrential downpour usually happened in summer season have caused average 38.29 times of the missing roadbed which support the railroad in recent 7 years. If a train would pass on this railroad which the roadbed was missed, there could be a huge accident and many people will die. But, the security issue is not satisfied because the method of sensing the missing roadbed is depending solely on the naked eye inspection by a person in charge. So, in this study, I would like to suggest the missing roadbed real-time sensing and train operation system to reduce the possibility of the railroad accident by controlling the operation of train when the missing roadbed condition would be sensed in the real-time system.