• Spatial Information Research
• /
• v.18 no.5
• /
• pp.55-61
• /
• 2010

This study was started for providing the application method of hyperspectral im age over extreme cold area as the Antarctic. Study area was Terra Nova Bay area which was decided as the candidate of 2nd Antarctic base station. For deciding last location of base station, many researchers tried to analyze the suitability of this study area. Among many suitability indicators, the location and stability of extracted bed rock area were very important. Using many spectral information of hyperspectral data, we tried detecting of bed rock and classifying four rock types. As additionally data, international spectral library of rock were used in this study. At the results, short-infrared wavelength bands were useful in the detection and classification of bed rock.

• The Journal of Engineering Geology
• /
• v.16 no.1 s.47
• /
• pp.85-96
• /
• 2006

This study was conducted to suggest a method to determine weighting values of each parameter of the RMR system considered with geologic characteristics of a study area. This study reviewed the weighting values of the RMR system for the Cretaceous sedimentary rocks distributed in Ulsan area. Based on the data of field survey at the study area, a multiple regression analysis was used to set up an optimal weighting values of the RMR parameters. For the multiple regression analysis, each parameter of the RMR and the slope gradient were regarded as the independent variable and the dependent variable, respectively. The analysis result suggested a modified weighting values of the RMR parameters as follows; 30 for the intact strength of rock; 18 for RQD; 8 for spacing of discontinuities; 32 for the condition of discontinuities; and 12 for ground water.

• Tunnel and Underground Space
• /
• v.23 no.4
• /
• pp.319-325
• /
• 2013

The objective of this study is to assess risks which might occur in connection with the storage of the highly compressed air in underground opening. Risk factors were selected throughout literature survey and analysis for the characteristic of CAES. Large risk factors were categorized in three components; planning and design phase, construction phase, and operation & maintenance phases. Large category was composed of 8 medium risk groups and 24 sub-risks. AHP technique was applied in order to analyze the questionnaires answered by experts and high-risk factors were selected by evaluating the relative importance of risks. AHP analysis showed that the operation & maintenance phases are the highest risk group among three components of large category and the highest risk group of eight medium risk groups is risk associated with the quality and safety. Risk having the highest risk level in 24 sub-risks is evaluated to be a failure of tightness security of inner containment storing compressed air.

• Journal of the Korean GEO-environmental Society
• /
• v.10 no.7
• /
• pp.167-177
• /
• 2009

This study investigates a failure mechanism of a tunnel shotcrete lining with respect to a concentrated load due to blocky rock mass. First of all, it is carried out to survey relevant researches to shotcrete failures by literature reviews and to numerically re-investigate the failure modes of shotcrete lining given by previous researches. Through this study, the failure modes are relocated with the conditions which induce each failure mode newly proposed by this study. In addition to this, the arching shape of tunnel lining, which has not been considered in the previous research despite of inherent geometrical characteristics in tunnels, is taken into consideration in numerical investigation on lining failure in this study. As a result, it is shown that more simplified failure modes can be found on the tunnel boundary condition and the corresponding failure condition to each mode can be different from ones of the previous study due to a tunnel arching effect.

• Tunnel and Underground Space
• /
• v.21 no.6
• /
• pp.460-470
• /
• 2011

Wave velocity was measured to define the weathering characteristics of rock and the strength evaluation of weathered rock on a target of the Aso gravestones with various sizes under the natural environment. As a result, the size correction method which was changed sample of the different size to one of the same size for evaluating wave velocity was proposed, and also suggested the NET (Normalized Elapsed Time) as a new weathering index of rock. In addition, the strength of the weathered rock was estimated from the weathering classification of rock using the NET. Wave velocity of welded tuff was high and didn't show velocity degradation, on the other hand, one of andesite was low and showed velocity degradation. The degree of weathering between rocks of the different size is considered to be comparable, applying the NET based on the on the $V_p/V_o$-NET curve. Furthermore, the classification of rock weathering stages using the NET based on the $S_c/S_o$-NET curve was available, and the estimation of strength for the weathered rock was also possible.

• The Journal of the Petrological Society of Korea
• /
• v.3 no.3
• /
• pp.234-240
• /
• 1994

The Wongyeong site, one of massive pinkish granite quarries in the Mungyeong area, was drilled to study the physical and chemical properties following the rock classification from fresh rock to highly, moderately and slightly weathered one. The physical properties such as specific gravity, absorption ratio, porosity and compressive strength were tested from the core samples. Specific gravity and absorption ratio are 2.37-2.64 and 0.27-1.87% respectively, while porosity and compressive strength are 0.70-4.38% and 110- 1, 695 kg/$cm^2$. With increased weathering, absorption ratio vs. porosity shows a positive correlation. The absorption ratio is in reverse proportion to compressive strength. Toward the surface in the drilled core, the $SiO_2$, CaO and $K_2O$ contents slightly decrease, but the $Al_2O_3$+FeO(t) contents increase by the enrichment of residual clay in the weathered rock.

• Tunnel and Underground Space
• /
• v.19 no.4
• /
• pp.275-286
• /
• 2009

In order to establish the causes and measures for technical risks that occur in various ground conditions when a subsea tunnel is excavated, it is important to configure expected risk scenarios. In addition, when the risk scenarios are classified because the scenario that occurs along all tunnel route and the scenario limited to some area are considered together, a logical framework with systematic and organized responses can be provided for project managements. In this research, project risk scenarios and management elements were configurated, and the project schedule was established for the management techniques to the risk scenario. The risk scenarios expected in a subsea tunnel were classified into a common risk scenario and a special risk scenario, and the concept which can combine with the project management elements was derived.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.19 no.4
• /
• pp.17-35
• /
• 2016

Earthquake-induced disasters are often more severe in locations with soft soils than firm soils or rocks due to differences in ground motion amplification. On a regional scale, such differences can be estimated by spatially predicting subsurface soil thickness over the entire target area. In general, soil deposits are generally deeper in coastal or riverside areas than in inland regions. In this study, a coastal metropolitan area, Incheon, was selected to assess site effects and provide information on seismic hazards. Spatial prediction of geotechnical layers was performed for the entire study area within the GIS framework. Approximately 7,000 existing borehole drilling data in the Incheon area were gathered and archived into the GIS Database (DB). In addition, surface geotechnical data were acquired from a walkover survey. Based on the built geotechnical DB, spatial zoning maps of site-specific seismic response parameters were created and presented for use in a regional seismic strategy. Site response parameters were performed to determine site coefficients for seismic design over the entire target area and compared with each other. Site classifications and subsequent seismic zoning were assigned based on site coefficients. From this seismic zonation case study in Incheon, we verified that geotechnical GIS-DB can create spatial zoning maps of site-specific seismic response parameters that are useful for seismic hazard mitigation particularly in coastal metropolitan areas.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1145-1148
• /
• 2007

한국을 비롯하여 논농사 중심지역에서는 하천 주변이 과거에는 농경지로, 그리고 오늘날은 도시지역으로 개발되어 하천의 원형이 거의 유지되지 못하고 있다. 하천은 수역과 수변으로부터 거리에 따라 여러 개의 이질적 생태적 공간이 이어지는 복합생태계로서 하나의 경관으로 볼 수 있다. 하천이 하나의 온전한 생태적 계로서 기능을 발휘하기 위해서는 이들을 모두 포함하는 하천의 원형이 복원되어야 한다. 현존하는 하천복원사업이 수변 구역의 복원에 초점을 맞추고 있지만, 진정한 복원이 이루어지기 위해서는 온전한 강변 식생의 복원이 선결과제이다. 본 연구에서는 유적군락의 형태로 잔존하는 강변 식생을 조사하여 식생복원 모델로 삼고자 한다. 수위와 침수체제에 의해 하천의 횡단구조를 수변, 홍수터 및 제방으로 구분한 후 각 지소의 적합한 식생단위를 구분하여 생태적 복원을 실현하기 위한 정보를 구축하였다. 수변식생으로는 달뿌리풀군락과 갈대군락이 자주 출현하고, 홍수터에는 갯버들군락과 키버들군락이 우세하였다. 그 중 전자의 식물군락은 하상재료가 거친 입자의 지소에 성립하고, 후자의 것은 미세한 입자의 지소에 성립하는 경향이었다. 제방역에는 버드나무군락, 다릅나무군락, 귀룽나무군락, 물푸레나무군락, 산사나무군락, 신나무군락(한탄강 지류), 참느릅나무군락, 물푸레나무-갈참나무군락(한탄강 본류), 오리나무군락(민통선 북방지역), 소나무군락, 황철나무군락, 느릅나무군락(소양강 상류), 왕버들군락(금강 중류) 등이 성립하였다. 이러한 식생정보를 하천의 지리적인 위치에 따라 구분하였고, 생태적 복원 시 도입식물을 결정하기 위한 자료로 삼기 위해 각 식생단위를 이루는 종 조성을 정보 체계화하였다.을 효율적으로 하기 위하여 Solar Unit으로부터 나오는 전기를 중전기에서 밧데리로 축전을 시키고 완전 충전 후에는 나머지 전기는 방전이 되도록 회로를 구성하였다. 사통수문 자원조사 결과에 의하면 현재 저수지에 물공급을 하는 수문은 취수탑 형식이 70% 이상을 차지하고 있으며 나머지 30%의 사통수문 중 원형수문비가 98% 이상을 차지하고 있다. 현재 대체에너지를 사용하는 저수지 사통수문은 없는 것으로 조사되었으며 전력을 사용하는 사통도 조사결과에 의하면 20% 이내로 나타났다. 이러한 결과는 향후 수리시설 개보수시 적은 예산으로 사업을 시행하는 경우 사통수문의 설치방향의 지표가 될 것으로 판단되며 수리시설의 운영관리에 대한 새로운 대안으로 제시할 수 있다.분류되었다. 지표 유거가 많아 배수등급이 매우양호로 분류되던 토양은 정 등(1995)의 분류와 비교하여 대부분 강우 유출 가능성이 큰 쪽으로 조정되었다. 새로운 수문학적 토양유형을 이용할 경우 낮은 토심에서 암반층이 발견되는 산림토양이 분포한 유역이나 산림, 밭 등에 식질 토양이 많이 분포하는 유역에서는 기존의 방법을 이용하는 것보다 강우 유출량이 높게 평가될 것으로 판단된다. 앞으로 강우 유출량 실측자료와의 비교를 통해 지속적인 보정을 하여야 할 것이며 특히 불투수층의 존재시 일괄적으로 D유형으로 분류된 토양의 경우 깊이에 따라 C 또는 D 유형으로 세분하여 조정할 필요가 있다.가 있었다. 에틸아세테이트분회물의 경우 디글로로메탄 분회물에 비해 다소 낮은 저해효과를 나타내었지만 250 ${\mu}$g/ml 농도에서 약 60%의 세포독성 효과를 나타내었다. 디클로로메탄 분획물과 에틸아세테이트 분

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.2
• /
• pp.125-133
• /
• 2014

In this study, TBM selection methods to meet soil and site conditions were presented. Factors and excavation equipment affecting TBM selection by soil and environmental condition were selected and classified. Weights between equipment and influencing factors selected were calculated by applying the AHP (Analytic Hierarchy Process) method. The results of the analysis influence factors, Ground condition was a major factor in objective factors and strength was a major factor in the hard condition of criteria factors and water pressure was a major factor in the soft ground condition of criteria factors. In Environment condition, existence of adjacent structures was evaluated more important than existence of feasible site. Lastly, Adequacy was verified through the deduction of results that coincide with input equipment by applying derived weights to actual site conditions.