• Title/Summary/Keyword: 대심도 토모그래피

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Rock Quality using Seismic Tomography in Deep Tunnel Depths (대심도 탄성파 토모그래피 탐사를 이용한 암반분류)

  • Koo, Ja-Kab;Kim, Young-Duck;Kwon, So-Jin
    • Journal of the Korean GEO-environmental Society
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    • v.3 no.3
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    • pp.5-13
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    • 2002
  • In tunnel design, geotechnical survey of over 200m tunnel depth is required because of its characteristical topography. For this reason, there are difficulties in collecting information of basic data in tunnel design because of large-scale costs in borehole tests, of limits to a geotechnical analysis by the existing refraction seismic survey and of analytical errors in steep mountainous area. Seismic tomography has many advantages as follows; 1) seismic velocity as absolute value is more reliable than electrical resistivity, 2) geotechnical analysis in deep tunnel depth is available by seismic velocity, 3) analytical errors is reduced in steep mountainous area. In this paper, it was found out a correlation of seismic velocity and Q in tunnel design in the neighborhood of the National Capital region and the reduction effect of tunnel construction cost using reliable rock quality by seismic tomography compared with by borehole data and electricity resistivity data.

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A proposal of seismic reference velocity ratio for the rock mass classification in tunnel area (터널구간 암반분류를 위한 탄성파 기준속도비의 제안)

  • Ko, Kwang-Beom;Ha, Hee-Sang;Lim, Hae-Ryong
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.09a
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    • pp.37-42
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    • 2005
  • Remote seismic tomography is regarded as one of the most valuable geophysical technique for the estimation of the rock mass classification in the tunnel area where hard data information such as drill logs are absent. But the results of rock mass classification based on the remote seismic tomography tend to be overestimated in practice. In this study, we propose the effective method to implement the seismic reference velocity ratio based on semblance for the improvement of rock mass classification. Also, to verify its feasibility, proposed technique was tested by using the real field data.

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A Case Study on Reinforcement of Ground and Foundation against Subsidence in Abandoned Mining Area (폐광지역 침하방지를 위한 지반 및 구조물기초 보강)

  • Kim, Do-Hyung;Choi, Chang-Rim;Kim, Dong-Hyun;Lee, Du-Hwa;Lee, Baek-Song;Je, Hae-Chan
    • Tunnel and Underground Space
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    • v.17 no.4
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    • pp.255-265
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    • 2007
  • As the mechanism and effect range of subsidence are altered according to the various conditions (the ground condition, the earth pressure, the geometric condition of underground cavity and the structure load), the analysis and prediction of subsidence in abandoned mining area are very difficult. Also, as the geological characteristics and the mining methods are differed in each mines, the application of the pre-existing reinforcements without improvement has a lot of difficulties and limits. In this study, the various underground investigation such as long-depth core drilling, seismic tomography and BIPS (borehole image processing system) were performed, the distribution of underground cavity and coal seam and rock relaxation condition were analyzed. And we predicted the type of subsidence and estimated the subsidence by theories of mining subsidence. With these results, we analyzed the mechanism of subsidence occurrence in the research object area. Finally, we improved existing methods which were applied to the abandoned mining area and also we established the rational reinforcement for the ground and structure foundation against each subsidence cause.