• 한국환경복원기술학회지
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• 제13권3호
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• pp.128-142
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• 2010

This study examined the actual conditions of quarries. aiming to offer preliminary data to help with restoration efforts of quarries after extracting rock material. The results are as follows. As for the current state of business, a classification of all sites surveyed showed the ratio of ceased operations: ongoing operations: quarries under restoration to be 58:5:37. Classified by the permit area, the ratio of the number of quarries with areas less than $20,000m^2$ (2ha) : between $20,000m^2$ (2ha) and $50,000m^2$ (5ha) : $50,000m^2$ (5ha) or more was 15:60:25. The classification by use of the rocks showed the ratio of construction aggregate (such as civil construction material) : building material : craft material to be 60:28:12. The ratio of quarrying methods of bench cut : slope quarry : vertical quarry wall is 40:18:42. It is indicated that 85% of all quarries surveyed are difficult to reclaim while 15% seem to be easier to restore. Among all surveyed, 34 sites were considered to be extremely difficult to restore. 17 of the 34 sites (50%) were quarry walls almost vertical that have been neglected after extraction. 16 of them (47%) were underground quarries that have left quarry walls deep under the ground. For the remaining 1 site, there doesn't seem to be any need for reclamation as it became totally flat after the extraction.

• 한국터널지하공간학회 논문집
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• 제19권1호
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• pp.57-70
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• 2017

본 연구에서는 광산이나 오일샌드 등의 분야에서 적용되고 있는 슬러리 파이프 마모량 측정 방법과 슬러리 파이프의 마모량 예측에 관련된 이론식들을 문헌연구를 통해 살펴보고, 실제 싱가포르 슬러리 쉴드 TBM 현장에서 주기적으로 측정한 직선부 슬러리 파이프의 두께 측정 자료로부터 평균 일일 마모율과 굴착거리당 마모율을 산정하였다. Bukit Timah Granite의 풍화등급에 따른 마모율을 구하였는데, 풍화토에 가까운 G (V) 등급 지반 및 G (III)/G (V)의 복합지반에서의 마모율이 G(I)~G (IV)의 암반 등급지반에 비해서 1.5배 높게 나타났다. 슬러리 파이프 마모율은 슬러리 운송속도에 비례하여 증가하는 경향을 보였다. 향후 지반특성 별 파이프 마모율과 합리적인 관리두께 선정을 통하여 보다 최적화된 슬러리 파이프의 교체 및 회전 주기를 산정할 수 있을 것으로 판단된다.

• 지질공학
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• 제13권2호
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• pp.157-170
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• 2003

본 연구는 국도 건설을 위한 절개면 공사중 붕괴된 사면의 붕괴 원인을 분석하고 안정성 해석을 실시한 후 적절한 대책안을 제시하기 위해 수행되었다. 붕괴 절개면은 매산-가곡간의 국도 도로공사 구간의 일부로서 풍화암과 연암으로 구성되어 있으며 국내 시방서에 따라 시공이 완료된 상태에서 붕괴가 발생하였다. 풍화암과 연암의 지반상태에서 1:1.5의 경사를 가지는 절개면의 붕괴는 국내에서 흔히 발생하는 사례는 아니다. 본 연구에서는 절개면의 붕괴 원인을 분석하기 위하여 현장조사, 시추조사, 계측, 사면안정해석 등을 수행하였으며 이들 자료를 이용하여 조사대상 절개면의 장기적인 안정성 확보를 위한 대책 방안을 제안하였다. 또한, 사면내에 연약층 등이 협재 되어 있고 습곡이나 단층 등이 발달되어 있는 경우에는 불연속면의 방향이 절취면의 방향과 $^30{\circ}$이상 사교하고 있더라도 사면 붕괴가 발생할 가능성이 있으므로 절개면의 설계에는 이들 지질구조에 대한 고려가 반드시 포함되어야 한다.

• 한국지반공학회지:지반
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• 제9권1호
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• pp.7-20
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• 1993

1988년 건설부에서 제정한 건축물에 대한 재진설계규준'에는 저면 전단력 산정시 지반계수가 1.0, 1.2, 1.5로 구분되어 있는데, 특히 얕은지반의 연약층에서 지반계수의 선정이 모호할 때가 많다. 또한 우리나라의 지반특성은 대부분 퐁화암 및 연암층이 20m이내에서 발견됨을 고려하여, 일차원 파전파 이론과 반무한 탄성이론 및 문헌을 통한 분석을 통해 지진 하중시 지반의 조건이 저면 전단력에 미치는 증폭효과를 비교분석하여 내진 설계시 적절한 지반계수 선택을 할 수 있도록 하였다.

• 화약ㆍ발파
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• 제28권2호
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• pp.37-49
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• 2010

도심지 특성상 주변구조물에 근접한 발파로 발생되는 지반진동은 인체에 간접피해와 구조물에 물적피해를 줄 수 있다. 설계단계 또는 시공 전 민원발생 시 구조물의 피해정도를 평가하는 방법으로는 단순 진동파형을 정량적으로 표현하는데 가장 접근성이 좋은 시추공 발파시험이 주로 이용되고 있다. 본 연구는 소량의 폭약으로 인위적인 진동에너지를 발생시키는 발파시험에 전자뇌관 기폭시스템을 처음 적용하였다. 전기뇌관 시추공 발파와 전자뇌관 시추공발파의 뇌관 지연시차 상관관계, 시험장소의 터널본선과 유사 암층에 시설된 구조물에서 측정한 PPV와 서로 다른 매개 층을 포함한 터널상부 지상도로에서 측정한 PPV의 상관관계, 기존 연구결과 얻어진 시추공발파 및 터널발파 PPV와의 상관관계를 비교 분석하여 시추공 발파의 유용성과 뇌관 지연시차의 중요성을 언급하고자 한다.

• 한국환경복원기술학회지
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• 제7권3호
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• pp.35-47
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• 2004

In order to study changes in vegetation pursuant to rooftop revegetation plantation methods, plantation methods for rooftop revegetation were divided into two types through an analysis of recent trends. Then, Planted plants and invasive plants on sites where the planting methods were introduced were monitored. Planting methods were divided into mono-layer meadow cover type and multi-layer planting cover type. They showed some differences in terms of the availability of wetland, the structure of vegetation layers, the planted species, and the material of mulching. According to the results of monitoring the two sample sites for different plantation methods, the number of invasive plants was higher in multi-layer planting cover type and the ratio of naturalized plants was higher by 30% in average in mono-layer meadow cover type. The main reason for such a result is that the natural soil used in the multi-layer planting cover type likely contained some seeds. Moreover, it's harder for invasive plant seeds to germinate in volcanic rocks than in natural soil. Also, it is attributable to wetlands available in multi-layer planting cover type and diverse living environments created by multi-layer planting. The reason of the ratio of naturalized plants being higher by at least 10% in mono-layer meadow cover type is the character of naturalized plants being stronger in unfavorable conditions than nature plants are. Accordingly, the germination rate in the volcanic rock mulching has likely contributed in raising the introduction and germination of naturalized plants. The results showed that multi-layer planting cover type using wetland creation and nature soil can increase the number of invasive plants and lower the ratio of naturalized plants. However, since seeds contained in the natural soil can affect the growth of planted plants, this needs to be clarified, It was judged that mono-layer meadow cover type may affect more greatly on the germination and growth of invasive plants than on those of planted plants, Its potential adoption in highly urbanized areas was examined. By complementing with the mutual benefits of each plantation method, it appeared possible to shift to a rooftop revegetation system suitable to the site.

• 화약ㆍ발파
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• 제23권4호
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• pp.1-18
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• 2005

고준위폐기물 처분시스템의 거동 실증을 위해 한국원자력연구소내에 추진되고 있는 지하처분연구시설은 고성능 폭약을 이용한 발파 기법에 의해 지하 화강암반내에 건설된다. $6m{\times}6m$ 크기의 터널을 굴착하기 위한 발파에 의한 진동 및 소음이 인접한 연구시설 및 하나로 원자로에 영향을 예측하기 위한 시험 발파가 실시되었다. 시험발파를 통해 얻어진 발파진동식을 이용한 원자력연구소내 주요시설에 대한 발파영향을 평가결과 설계기준에 비해 훨씬 낮은 것으로 파악되었다. 굴착 진행에 따른 소음, 진동값을 측정하였으며 진동값의 경우 발파진동식으로 추정한 값보다 더 낮게 나타났다. 따라서 원자력연구소내 지하에 280m 규모의 처분연구시설을 건설하기 위한 발파작업으로 연구소내 주요 시설에 미칠 영향은 미미할 것으로 판단된다.

• 한국환경복원기술학회지
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• 제9권2호
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• pp.81-89
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• 2006

The purpose of this study was to evaluate the applicability of small RC(radio controlled) helicopter and single lens reflect camera as SFAP(Small Format Aerial Photography) aquisition system to monitor the vegetation coverage of wetland. The system used to take pictures of small artificial wetland were a common optical camera(Nikon F80 with manual lens whose focal length was 28mm) attached to the bottom of a RC helicopter with a 50 cubic inch size glow engine. Three hundreds pictures were taken at the altitude of 50m above the ground, from 23rd June to 7th September 2005. Four from the images were selected and scanned to digital images whose dimension were 2048${\times}$1357 pixels. Those images were processed and rectified with GCP(Ground Control Poins) and digital map, and then classified by the supervised- classification module of image processing program PG-steamer Version 2.2. The major findings were as follows ; 1. The final images processed had very high spatial resolution so that the objects bigger than 30mm like lotus(Nelumbo nucifera), rock and deck were easily identified. 2. The dominant plants of the monitoring site were Monochoria ragianlis, Typha latifolia, Beckmannia syzigachne etc. Because those species have narrow and long leaves and form irregular biomass, the individuals were hardly identifiable, but the distribution of population were easily identifiable depending on the color difference. 3. The area covered by vegetation was rapidly increased during the first month of monitoring. At the beginning of the monitoring 23th June 2005, The rate of area covered by vegetation were only 34%, but after 27 and 60 days it increased to 74%, and the 86% respectively.

• 기술사
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• 제25권4호
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• pp.102-108
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• 1992

This study was carried to find out the soil characteristics of landslide site and to develope landslide prediction method by seismic refraction prospecting. For these aims, landslide condition and travel time were investigated at 68 Landslide sites over the country during 1990 to 1991. The results were as follows. 1. The surface of rupture was included mainly in C layer. Its Hardness was less than 3kg / $\textrm{cm}^2$ at the upper pare of landslide. 2. When the profile line length was 20m, the range of travel time was 40 to 90 msec. The travel time did not differ between bedrocks. 3. Refraction distance ranged from 1 to 7m and mean of that was 2.5m. Travel time was increased according to receiving distance without large variance in the refraction distance but that was appeared large variance out of the refraction distance on slope that has shallow soil depth and discontinuous ground surface. Therefore, the spread distance must be shorten to 10-l5m. 4. The seismic velocity at the first layer(layer of rupture) was less than 500m1sec by degree of weathering and the velocity at the second layer decreased in order of Granite> Granitic gneiss >Sedimentary rock. 5. The first layer observed by seismic refraction was contained C layer that has parent material and weathered rocks of hardness 10-20kg/$\textrm{cm}^2$. 6. Among the range of seismic velocity was less than 200m/sec in 63% of the total plots, 200-300m/sec in 34% and 300-500m /sec in 3%. 7. There was a proportional relationship between seismic prospecting soil depth and executive soil depth, and seismic propection soil depth was about 10 to 20cm deeper than the order.

• Structural Engineering and Mechanics
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• 제54권1호
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• pp.169-188
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• 2015

This study presents the effects of the spatial variation of ground motions in a hard rock site on the seismic responses of a base-isolated nuclear power plant (BI-NPP). Three structural models were studied for the BI-NPP supported by different number of lead rubber bearing (LRB) base isolators with different base mat dimensions. The seismic responses of the BI-NPP were analyzed and investigated under the uniform and spatial varying excitation of El Centro ground motion. In addition, the rotational degrees of freedom (DOFs) of the base mat nodes were taken to consider the flexural behavior of the base mat on the seismic responses under both uniform and spatial varying excitation. Finally, the seismic response results for all the analysis cases of the BI-NPP were investigated in terms of the vibration periods and mode shapes, lateral displacements, and base shear forces. The analysis results indicate that: (1) considering the flexural behavior of the base mat has a negligible effect on the lateral displacements of base isolators regardless of the number of the isolators or the type of excitation used; (2) considering the spatial variation of ground motions has a substantial influence on the lateral displacements of base isolators and the NPP stick model; (3) the ground motion spatial variation effect is more prominent on lateral displacements than base shear forces, particularly with increasing numbers of base isolators and neglecting flexural behavior of the base mat.