• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.910-920
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• 2008

In Korea, more than 70% of the territory consists of mountains. Therefore, the construction of roads and railways has generally involved with a steep rock slope in which the event of rockfalls are often occurred due to the weathered rock conditions and rainfalls etc. This is dangerous when the rock falls into the road and railway on which vehicles and trains are running. In order to prevent such rockfalls, the rockfall protection fence consisting of post, wire rope, and PVC coating steel net has most used at the bottom of rock slopes. In a general practice, an absorbing rockfall energy, 50kJ is specified by the Ministry of Construction and Transportation. However, questions still remain about whether the rockfall protection fence works effectively or not. In this study, a typical wire rope used in the standard rockfall protection fence was replaced by the high carbon steel wire rod and to validate its capacity of rockfall energy absorbing the field rockfall tests were conducted. The testing results show that a new rockfall protection fence using the high carbon steel wire rods can absorb the rockfall energy more than 50kJ and 20% of construction cost was saved in comparison with the previous rockfall protection fence.

• 화약ㆍ발파
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• 제30권2호
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• pp.21-28
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• 2012

사면 절취 및 도심지 터파기 등 인공적으로 사면을 형성하는 경우 경제적이고 효율적인 공법으로 화약을 이용한 발파공법이 많이 사용되고 있다. 절취면 보호를 위해 대상 암반에 손상을 주지 않고 암반이 가지고 있는 자연적인 강도를 그대로 유지할 수 있도록 발파하는 것이 중요하며 사회적으로 문제 시 되는 발파공해를 고려하여 발파진동을 저감할 수 있는 공법이 필요하다. 본 연구에서는 평활한 절취면 형성을 위하여 도폭선에 폭약을 등간격으로 배치하고 장약의 방법과 전색의 방법을 달리하여 발파를 진행하였다. 4가지 패턴을 사용하여 총 60공에서 20회 발파를 실시하였으며 발파원으로부터 15~120m 거리에서 발파진동소음측정기를 사용하여 진동속도를 측정하여 310개의 데이터를 획득하였다. 측정된 진동속도 데이터를 분석하여 발파진동을 저감하고 효율적이고 경제적으로 절취면을 보호할 수 있는 방법을 연구해 보았다.

• 한국환경복원기술학회지
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• 제13권3호
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• pp.73-83
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• 2010

A technology using continuous fiber soil reinforcement system for the creation of ecological restoration in a damaged area has been developed and introduced. The continuous fiber soil reinforcement system (Geofiber system) is an environmentally friendly slope protection technique that continuous fiber soil reinforced layers are constructed with green plantation on cut slope. The characteristics of this system in terms of the strength and hydraulic performance, and the vegetation were investigated in this study. The main objectives of this comparative study was to quantify the potential contribution of geofiber system for the revegetation on the cut slope in a damaged area. A Geofiber system was constructed to reinforce the lower layer of slopes and revegetation methods including wood chips were carried out on the upper layer by machineries. The results of monitoring during 3 years on cut slopes were as follows : 1) All the quadrat existed in the proper range for vegetation. 2) Species richness was 4.4 (site-1) and 18.5 (site-2) respectively. 3) The averaged coverage rates of quadrats was 90%. It is remarkable that the continuous fiber soil reinforcement system would be capable of applying to a damaged area and also would serve maintaining a healthier environment for floras. However, it behooves to continue monitoring on succession of vegetation for ecological restoration.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.612-615
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• 2007

The environmental damage caused by river-improvement and slope of incision cliff can dest habitations of animate nature and it takes long time for restoration. River system constructed with stability of flood control, fine biotope, harmony with surroundings should be need to protect and restore nature. Therefore, in this study, conduct comparative experiment in various methods which are stable hydraulically and develop vegetation on revetment of bank, stream bed protection and disaster prevention aspect.

• 한국해양공학회지
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• 제1권1호
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• pp.84-93
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• 1987

A beach nourishment method can be used as one of the beach erosion protection methods which may keep coastal environments whithout constructing coastal structures on the HAE UN DAE beach. The beach nourishmens is affected by a natural condition and artificial condition;a natural condition includes conditions of bottom slope, diameter of bottom materials and waves, and artificial conditions include deposit position, method, diameter and quantity of the nourishing sand. It has accomplished to obtain the deposit position and the best diameter of the nourishing sand from a two-dimensional hydraulic model test, which simulates the erosional HAE UN DAE beach. In this study, the protection of the beach erosion can be maximized when the nourishing sand of 3.3mm in diameter, which is about 5.5.times of the bottom materials in diameter, is deposited layerly in front of the breaker zone which has a water depth of 4.6m.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2001년도 추계학술발표회 논문집
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• pp.45-57
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• 2001

An alternating current (AC) corrosion using coupon has been studied. Coupons were applied in terms of AC voltage from high value to low value through the survey of AC voltages on buried gas transmission pipeline over the country. Parameters such as AC current density of coupon, AC voltage, cathodic protection potential, soil resistivity and frequency were monitored continually. Corrosion induced by AC was observed even under cathodically protected condition that met cathodic protection criterion(: below -850mv vs. CSE). Corrosion rate was affected mainly not by AC voltage but by both of frequency and AC current density. An experimental corrosion rate relationship could be obtained statistically, in which AC corrosion rate increased linearly with effective AC current density and its slope was 0.619.

• 한국환경복원기술학회지
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• 제4권2호
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• pp.26-35
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• 2001

We are, now in the 21st century, that environmental preservation and the campaign for bio-diversity protection are very important issues the government must deal with as nation's main policy. To make road and building construction, housing land service, construction of golf fields, and various development works, we have made artificial topographical alterations and as a result, the cut-slop has been increased. However, without the proper study and clear planning, revegetation for the stability of the cut-slop has worked out. These efforts now are causing derangement of an ecosystem and spoiling the nature without considering for ecological adaptation. Therefore, we are going to find out the Revegetation Method to Cut-Slopes considering both the ecological adaptation and harmony with the nature.

• Corrosion Science and Technology
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• 제4권1호
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• pp.1-7
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• 2005

An alternating current (AC) corrosion on buried pipeline has been studied using coupon and ER probe. Coupons and ER probes were applied to the sites from high value of AC voltage to low value based on the survey of AC voltages on buried gas transmission pipeline over the country. Parameters such as AC current density of coupon, AC voltage, cathodic protection potential, soil resistivity and frequency were monitored continually. Corrosion induced by AC was observed even under cathodically protected condition that met cathodic protection criterion (; below -850 mV vs. CSE). Corrosion rate was affected mainly not by AC voltage but by both of frequency and AC current density. An experimental corrosion rate relation could be obtained according to effective AC current density, in which AC corrosion rate increased linearly with effective AC current density, and its slope was 0.619 in coupon method and 0.885 in ER probes.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.78-88
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• 2018

The liberalization of electricity market and environmental concerns are the major driving forces for the development of Distributed Generation (DG). The mode of grid-connected wind power generation is becoming popular and has matured as a reliable DG technology. The voltage generated by the wind generator is stepped up to the higher voltage by the transformers before connecting to the grid. Operating algorithm of the differential relays for transformer protection used in the wind farms need to be modified to take care of the dynamic nature of fault current caused by the intermittent nature of the wind power. An algorithm for the differential relay is proposed in which dual slope characteristics are adjusted with varying fault level situation according to the wind generator in service as well as with the wind speed. A case study conducted for a typical wind farm shows that the proposed method avoids mal-operation of the differential relay in varying wind power conditions.

• 한국지반환경공학회 논문집
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• 제10권6호
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• pp.49-60
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• 2009

본 연구는 기존의 낙석방지울타리에 적용되는 와이어로프를 경강선으로 대체하고 소재 및 체결부에 대한 실내성능실험과 더불어 현장에서의 수직낙하시험을 통해 전체적인 에너지 흡수능력을 평가하여 새로운 낙석방지울타리를 개발하는데 있다. 12단 경강선 적용 낙석방지울타리의 수직낙하시험 결과, 국내 낙석방지울타리에 기준으로 적용되는 흡수에너지인 50kJ 이상의 에너지를 흡수하는 것으로 나타났다. 또한 경강선 단수가 12단에서 16단으로 증가함에 따라 에너지 흡수능력도 향상되었다. 이러한 새로운 낙석방지울타리를 도로공사 절취사면 현장에 성공적으로 적용하였다. 그 결과, 시공성은 기존에 비해 별차이가 없는 것으로 나타났으나 미관상 전체적으로 심플하고 깨끗한 이미지를 연출할 수 있었다. 경제성 분석결과에 있어서는 전체 건설비용에 있어 기존 대비 약 20% 정도 절감되는 것으로 나타났다.