• Economic and Environmental Geology
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• v.52 no.2
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• pp.189-197
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• 2019

HLW (High Level Radioactive Waste) is one of the problems that must be solved in the countries that implement nuclear power generation. Most countries that are concerned about HLW treatment are considering complete isolation from human society by disposing them deep underground. For perfect isolation, understanding the characteristics of underground rocks is very important. In particular, understanding the characteristics of discontinuity as a path way is one of the first things in order to predict the movement of exposed nuclear species to the surface. In this study, we used 500m underground core samples obtained from granite and gneiss area. The purpose of this study is to understand the characteristics of the discontinuities in each rock type and to analyze the properties of the joints in the underground relative to the surrounding environment. For this purpose, the types of discontinuities were classified and the distribution of each discontinuity were analyzed through visual analysis of the each sample obtained at 500m underground. This study can be used as a basic data for understanding the properties of discontinuities in the rock of the survey area and it can be also used as an important data for understanding the distribution characteristics of discontinuities according to the rock types.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.369-380
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• 2005

This study describes image-based approach for efficient and objective evaluation method of the rock slope stability. Three-dimensional rock slope model was reconstructed by processing stereo digital images. The model provided fundamental information for geospatial analysis of the rock slope. Methods to extract three-dimensional information about discontinuity on the rock slope and to estimate roughness of the rock surfaces were suggested. The results show that stereo digital images have potential to provide information for both quantitative and qualitative analysis of rock slope. In addition, visualization of the results increases efficiency and benefit in evaluating rock slope stability.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.3-16
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• 1999

This paper presents the results of sensitivity analysis based on an example study to verify a newly developed reliability-based model for rock slopes considering uncertainties of discontinuities and failure modes-plane, wedge, and toppling. The parameters that are needed for sensitivity analysis are the variability of discontinuity properties (orientation and strength of discontinuities), the loading conditions, and the rock slope geometry. The variability in orientation and friction angle of discontinuities, which can not be considered in the deterministic analysis, has a great influence on the rock slope stability, The stability of rock slopes including failure modes is more influenced by the selection of dip direction of cutting rock face than any other design variables, The example study shows that the developed reliability-based analysis model can reasonably assess the stability of rock slope.

• Journal of Korean Association for Spatial Structures
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• v.8 no.3
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• pp.83-90
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• 2008

It is hard to predict the mechanical characteristics of discontinuous stone masonry structures by the static analysis method, because of irregularity of face stones and also due to randomness of backfill materials. Inversely, one can estimate the mechanical characteristics by comparing the natural frequencies between measured and computed. The aim of this paper is to investigate the computational modeling method of ancient stone arch bridges in Korea and to find the factors influencing their dynamic characteristics. The results revealed that the rigidity of spandrel walls and backfill materials are the most important factors influencing the natural frequencies of stone arch bridges.

• Explosives and Blasting
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• v.22 no.3
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• pp.1-12
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• 2004

In bench blasting, rock fragmentation is one of the most important factors determining productivity. Rock fragmentation could be affected by various conditions and these were hewn that rock joint conditions and in-situ block sizes were the biggest effect on it. This research is focused on what or how to influence on rock fragmentation according to relation between blasting conditions and the in-situ rock conditions such as rock joint conditions and in-situ block size. Field measurements were carried out in 3 open pit limestone mines, where in-situ rock conditions and blasting conditions were fully investigated. The results show that the parameters interact with blasting conditions complicatedly and especially in-situ block size has bigger effects. Dip direction of major joint set also can affect on fragmentation. Mean fragment size become smallest when dip direction of major joint set is about $30^{\circ}$ with the bench direction. The reason is considered to be come from difference of propagation paths of elastic wave.

• The Journal of Engineering Geology
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• v.4 no.1
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• pp.13-28
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• 1994

Hydrogeologic characteristics of crystalline rock including discontinuities is defined by the hydraulic data from the in situ test and by analytical method. Methodology and procedure of the in situ test are used in accordance with test purpose, site condition and characteristics of host rock Hydraulic conductivities in crystalline rock including discontinuifies such as fractured zone and joint, are defined by packer test and slug test. The results indicate Hvorslev' s theory of ground water flow in NX borehole, that the shorter of test interval is, the higher hydraulic conductivity is. This is an indicafion of the fact that the hydraulic rneasured were governed by scale effect of test interval, even at same borehole. According to the result of packer tests in two boreholes, it is understood that hydraulic conductivifies show variations according to the effect of as order of tests. In the comparison of hydraulic conductivifies from both of open borehole tests, the results are relatively well correrated in values. The hydraulic conductivity in the test intervals induding hydrogeologically significant discontinuity shows relatively higher value of hydraulic conductivity in vertical distribution of full depth.

• Explosives and Blasting
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• v.24 no.1
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• pp.21-28
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• 2006

Rock mass classification systems such as RMR and Q system have been widely served as a simple empirical approach for the design of various rock mass structures in the stage of site survey as well as under the construction. For the RQD determination, the boring is partially carried out and what is more, the survey boring is not normally carried out under construction. Therefore RQD is frequently determined by empirical method or indirect method. Since it is difficult to determine the discontinuity characteristics such as RQD, spacing, persistence, filling and so on, it is essential to develop suitable and simple systems without drilled core and a cert 없 n number of representative parameters. One of the primary objectives of the classification systems for a practicing engineer has been to make it simple to use as a preliminary design tool for the structures in rock mass. In the present study, the modifications for both the RMR and GSI system are suggested by authors to introduce new classification system as well as to improve the scope of some of the existing classification systems for a practicing engineer.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.294-303
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• 2003

The structural behaviour of rock mass structure, such as tunnel or slope is critically dependent on the various characteristics of discontinuities. Therefore, it is important to survey and analyze discontinuities correctly for the design and construction of rock mass structure. One inevitable Procedure of discontinuity survey and analysis is joint set identification from a lot of raw directional joint data. The identification procedure is generally done by a graphical method. This type of analysis has some shortcomings such as subjective identification results, inability to use extra information on discontinuity, and so on. In this study, a computer program for joint set identification based on the fuzzy clustering algorithm was implemented and tested using two kinds of joint data. It was confirmed that fuzzy clustering method is effective and valid for joint set identification and estimation of mean direction and degree of clustering of huge joint data through the applications.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1996.03a
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• pp.83-94
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• 1996

지하 암반구조물의 안정적 설계 및 효율적 시공을 위해서는 공동설계 및 거동예측에 필요한 지질공학적 자료의 획득이 가장 중요하다. 현재 절리 등의 불연속면을 포함한 현장암반의 역학적 특성계수 및 응력 상태에 대한 조사기법들이 다양하게 개발되어 신뢰성 있는 분석결과를 제공하고 있다. (중략)

• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.317-331
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• 2005

[ ${\circ}$ ] 지반 분포 상환 파악 : 도모그래피 기법 ${\circ}$ 지반의 불연속면 파악 : BHTV, BIPS 및 TSP ${\circ}$ 지반의 횡파 속도 파악, 내진 설계: 표면파 기법, 다운홀 및 크로스홀 ${\circ}$ 시추공의 심도 별 원위치 물성 산출: 밀도 검층, Suspension PS 검충