• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.11a
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• pp.213-234
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• 2002

우리 나라는 70년대까지 광업은 부흥하였으나, 그 이후 급속히 위축되면서 80년대 이후 거의 대부분 광산들이 폐광 또는 휴광된 실정이다. 그 결과 현재 전국 각지에 다수의 폐갱도가 존재하게 되었으며, 이제는 지반침하 및 각종 침출수의 원인자로 간주될 정도이다. 최근 지자체에서는 이런 폐갱도를 지역 자원으로서 가치를 인정하고 지역 활성화를 위해 재 이용하려는 움직임이 보이고 있는데, 구체적으로는 관광시설, 연구시설, 농업생산시설, 저장시설, 폐기물처리시설 등이다. 일본은 폐광된 금속광산 재활용을 위해 입지여건과 주변지역, 입갱 가능성 등 기초조사를 하였다. 조사결과 폐갱도의 문제점으로 입갱이 가능한 광산이 적다는 점을 들 수 있다. 대부분의 광산은 갱구가 함몰되었거나, 갱내에 지하수가 차 있어 접근이 불가능한 경우가 대부분이다. 비교적 양호한 암반 경우는 서브 레벨 스토핑, 잔주, 주방식 등의 채굴법에 의해 대규모 공동이 잔존하고 있는 경우도 있지만 그리 많지 않았다. 폐광된 광산 재활용 여건은 우리 나라와 일본이 대동소이 경우로 현실적으로 활용이 가능한 폐광은 많지 않으며 활용코자 할 때에는 기존갱도를 활용하면서 암반이 견고한 곳에 새로운 갱도를 설치하여야 한다. 그러나 몇몇 곳에서는 매우 유용하게 잘 활용되고 있는 곳도 있고, 연구 검토하면 충분한 활용성이 있다고 생각되는 곳도 있다. 그러므로 현재의 상황을 보고 판단할 것이 아니라, 활용기술과 접목해서 활용성을 검토함으로써 불용 자산의 유용화 방안이 검토되어야 할 것이다. 현재 가행중인 광산은 입지여건 및 암반이 양호하고, 대형갱도를 굴착하는 석회석광산 등을 선택하여 폐광 후 활용이 가능토록 채광기술 발전시켜 나가야 하며, 인간 중심적인 시설 또는 산물 중심적인 시설로 구분하여 폐광 후 복구비용을 우선 지원하는 방식 등을 통하여 시추, 탐광굴진, 현대화, 수갱굴착, 자금융자 등을 지원하는 우리 공사와 산업자원부가 지자체, 산림청, 건교부, 농림부 등과 연계하여 종합적인 지원육성책을 마련하여야 할 것이다. 결과적으로, 지방자치단체 등에서 관심을 갖고 있는 저장시설, 폐기물처리시설, 관광시설, 농업생산시설, 연구시설 등을 중심으로 ＆apos;광산 채굴적을 미래에 어떻게 활용한 것인가＆apos;를 선진외국 사례를 벤치마킹하고, 연구ㆍ검토하여 친환경적인 광산개발이 되도록 기본적인 방향과 개념을 갖도록 하여 관련 정책을 계획적이고, 체계적으로 수립 일관성 있게 추진해 나가야 할 것이다.

• Tunnel and Underground Space
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• v.15 no.5 s.58
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• pp.359-368
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• 2005

In case the overburden of a tunnel is too low to adopt NATM, cut and cover method generally can be chosen as alternative. However, in tunneling some area with very low or no overburden between two mountains, the cut and cover method requires additional construction of a couple of tunnel portals and the maintenance of portal slopes until backfilling is completed. As a solution for this problem, increasing the tunnel overburden by raising the ground level can be effective. This paper presents the case study for tunneling at C240 site in Taiwan High Speed Railway(THSR) in which soil-cement filling method was used for pre-banking before tunnel excavation. Cement content of filling material was $2\~4\%$ and thickness of filling a round was $130\~250\;mm$. The stability evaluation for the soil-cement slope and concrete lining of low cover tunnel was conducted by numerical analysis.

• Tunnel and Underground Space
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• v.23 no.2
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• pp.87-98
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• 2013

Around 70% of Korea is mountainous, an increase in tunnel construction. It's due to the growing interest of the public for the environment and land required for the road construction is very scarce. During construction of 'Daedong 1 tunnel' in the expressway expansion project between Naengjeong and Busan, there are shallow shaft due to this tunnel located in the valley and the shafts are separated, and penetrating location change was inevitable for construction was delayed because of complaint. So, we change the position of the penetrating by applying multi-channel TSP, and conducted a stability analysis. The analysis results showed that there is no problem on the stability of the tunnel. To secure the construction of additional stability, We installed instrument, performed mechanical excavation, added reinforcement at shallow shaft and conducted bench cut.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1532-1548
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• 2008

The tunnel type spillways is under construction to increasing water reservoir capacity in Dae-am dam. The tunnel outlet was planned to be made after installing slope stabilization system on natural slope there. Generally, the tunnel outlet is made perpendicularly to the slope, but in this case, it had to be made obliquely to the slope for not interrupting flow of river. Because of excavation in condition of natural slope caused to deflecting earth pressure, the outlet couldn't be made. So, artificial ground made with concrete that it was constructed in the outside of tunnel for producing the arching effect which enables to make a outlet. We were planned tunnel excavation was carried out after artificial ground made. Artificial ground made by poor mix concrete of which it was planned that the thickness was at least 3.0m height from outside of tunnel lining and 30cm of height per pouring. Spreading and compaction was planned utilized weight of 15 ton roller machine. In order to access of working truck, slope of artificial ground was designed 1:1.0 and applied 2% slope in upper pert of it for easily drainage of water. In addition to, upper pert of artificial ground was covered with soil, because of impaction of rock fall from upper slope was made minimum. The tunnel excavation of the artificial ground was designed application with special blasting method that it was Super Wedge and control blasting utilized with pre-percussion hole.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.113-122
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• 2013

Recently there has been increased interest for the portal and shallow tunnel for an eco-friendly tunneling method. Semi cut & cover tunnel excavation techniques applied to concrete slab and construction and a growing number of cases, but there is no load combinations and arch concrete cross section for the applicable standards. Therefore, in this study, ground conditions and tunnel overburden thickness, thickness of backfill, overburden surface slope angle changes to a variety of conditions in order to propose standards for the semi cut & cover method was performed numerical analysis. Regression analysis method to the analysis of the results of numerical analysis, and linear regression equations derived to classify and organize a rational, economical, and safe semi cut & cover tunneling method based proposed.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.433-437
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• 2008

It's essential to build an earth retaining structure at the beginning and end point of a tunnel constructed in a colluvium area. A large scale of colluvial soil may cause a problem to the stability of the excavation ground. An excavation in colluvium has different behavior characteristics from those in a sandy soil due to unstable elements and needs counter measures for it. There are few systematic research efforts on the behavior characteristics of an earth retaining structure installed in colluvial soil. Thus this study set out to collect measuring data from an excavation site at the tunnel pit mouth in colluvium and set quantitative criteria for the safety of an earth retaining structure. After comparing and analyzing the theoretical and empirical earth pressure from the measuring data, the lateral earth pressure distribution acted on the earth retaining wall was suggested.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.419-425
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• 2009

Recently, the number of shallow tunnel construction increases to improve the structural safety and environment-friendliness. In Semi-Cut and Cover Method, ground is excavated to the crown arch level and braced rib arch is set to backfill before the excavation of lower face. Semi-Cut and Cover Method is proposed to solve the problems occurred by the conventional Cut and Cover Method, such as unstability, high-cost and the large cutting slope to be reinforced. In this paper, the behaviors of Braced Rib Arch in shallow tunnel excavated by semi-cut and cover method was studied. Model tests in 1:10 Scale were performed in real construction sequences. The distance between supports of rib arch was 1.8 m and the length of spacer was 1.0 m. the size of test pit was 4.0 m (width)$\times$3.3 m (length) 4.0 m (height) in dimension. Tests results show that backfill load acting on arch was smaller than that in the conventional Open-Cut Method.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.53-62
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• 2014

In Korea, in general, separation distance between existing parallel tunnels was set at two to five times as distant as the diameter of the tunnels according to ground conditions. Recently, however, actual applicability of closely spaced parallel tunnels whose distance between tunnel centers was shorter than the diameter has increased due to environmental damages resulting from massive cutting, restriction in purchase of required land, and maintenance of linear continuity. In particular, when the pillar width of tunnel decreases, the safety of pillars affects behaviors of the tunnel and therefore the need for diverse relevant studies has emerged. However, research so far has been largely confined to analysis of behavior characteristics of pillars, or parameters affecting design, and actually applicable and quantitative data have not been presented. Accordingly, in order to present a stability evaluation method which may maximally reflect construction conditions of spots, this study reflected topographical and stratigraphic characteristics of the portal part with the highest closeness between the tunnels, simulated multi-layer conditions with rock mass and complete weathering, and assessed the degree of effect the stability of pillars had on the entire tunnels through numerical analysis according to changes in pillar width by ground strength. This study also presented composite analysis result on ground surface settlement rates, interference volume rates, and average strength to stress and a formula, which may be applicable to actual work, to evaluate safety rates of closely spaced parallel tunnel pillars and minimum pillar width by ground strength based on failure criteria by Hoek-Brown (1980).

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.195-206
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• 2014

In this study, soil contamination maps related to Cu and Pb were created at the Busan abandoned mine in Korea using a handheld X-Ray Fluorescence(XRF) and Geographic Information Systems(GIS). Hydrological analysis was performed using the Digital Elevation Model(DEM) of the study area to identify the flow directions of surface runoff where pollutants can be dispersed from the soil contamination sources. 24 locations for measuring the soil contamination related to Cu and Pb were selected by considering the result of hydrological analysis. The results measured at the 24 locations using the handheld XRF showed that the highest value of Cu contamination is 8,255ppm and that of Pb is 2,146ppm. The field investigation data were entered into ArcGIS software, and then soil contamination maps regarding Cu and Pb with a 5m grid-spacing were created after performing spatial interpolations using the ordinary kriging method. As a result, we could know that high concentrations of Cu and Pb are presented at the waste and tailings dumps around the abandoned mine openings. This study also showed that the handheld XRF and GIS can be utilized to create soil contamination maps related to Cu and Pb in the field.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.123-131
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• 2003

Geophysical surveys(electrical resistivity, self-potential, seismic refraction, GPR) were conducted to investigate the physical properties of the subsurface, and to delineate the flow channel of leachate from a AMD(acid mine drainage), buried rock wastes and tailings, and drainage pipes at an abandoned mine(Kwangyang mine). Especially in rainy season the sites appear to be abundant in AMD leachate, characterized by electrical conductivities of 0.98-1.10 ms/S. Electrical resistivity sections indicate that the leachate flows running in two directions at southern part rise up through the narrow fracture zones at the central part and contaminates the surrounding soil and stream. Such schematic features at the anomalous zone are well correlated with negative peaks in self-potential data, the limited penetration depth in GPR data and low velocity zone in seismic refraction data. Shallow high-resistivity zone is associated with the buried rock wastes which cause the diffractions in GPR image. In addition, the events at depth of approximately 1-1.25 m in GPR sections must be the metal pipes through which AMD is drained off to the inner bay.