• The Journal of Engineering Geology
• /
• v.21 no.1
• /
• pp.15-24
• /
• 2011

To clarify the distribution of joints and fracture zones in the Cheongju granitic mass, we analyzed drill-core and geophysical well-logging data obtained at two boreholes located 30 m from each other. Lithological properties were investigated from the drill-core data and the samples were classified based on the rock mass rating (RMR) and on rock quality designation (RQD). Subsurface discontinuities within soft and hard rocks were examined by geophysical well-logging and cross-hole seismic tomography. The velocity structures constructed from seismic tomography are well correlated with the profile of bedrock depth, previously mapped from a seismic refraction survey. Dynamic elastic moduli, obtained from full waveform sonic and ${\gamma}-{\gamma}$ logging, were interrelated with P-wave velocities to investigate the dynamic properties of the rock mass. Compared with the correlation graph between elastic moduli and velocities for hard rock at borehole BH-1, the correlation points for BH-2 data showed a wide scatter. These scattered points reflect the greater abundance of joints and fractures near borehole BH-2. This interpretation is supported by observations by acoustic televiewer (ATV) and optical televiewer (OTV) image loggings.

• Proceedings of the KSEG Conference
• /
• 2005.04a
• /
• pp.157-164
• /
• 2005

BIPS와 Televiewer를 이용하여 10개의 지하수 관측공에서 획득된 1,591개 불연속면을 분석하여 지하수 유동과의 관계를 비교${\cdot}$분석하였다. 연구지역 내의 지형은 산계가 잘 발달된 계곡형 지형이며, 수계의 발달은 매우 미약하다. 연구지역 주변에는 북북동-남남서 방향의 양산단층과 동래단층이 발달되어 있으며, 연구지역 내에는 EW방향의 선구조도 발달되어 있다. 지하수공내에서 조사된 불연속면의 주 방향은 위성사진에서 판독된 선구조의 방향과 대부분 일치한다. 지구통계기법을 이용하여 작성된 지하수위 등고선도에서 추정된 지하수 유동방향과 유향${\cdot}$유속기에서 측정된 지하수 유향은 거의 일치하지만, 단열암반에 발달된 불연속면의 방향과 지하수 유동방향은 2가지로 해석되었다. 첫째는 단열암반에 발달된 불연속면의 방향과 지하수 유동방향이 잘 일치하는 경우(BH-01, 03, 04, 12공), 둘째는 불연속면의 방향과 지하수 유동방향이 잘 일치하지 않는 경우(BH-02, 05, 07, 11) 이다. 지하수 유동방향이 불연속면의 방향과 일치하지 않는 경우는 지형의 변화에 더 영향을 받는 것으로 나타났다. 따라서 단열암반 내에서 지하수의 유동은 단열의 방향성에 영향을 받지만, 지형의 특성에도 큰 영향을 받는다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.284-287
• /
• 2005

The flow of groundwater in fractured medium is related to the geometric characteristics of the fracture system. And a fracture aperture and a fracture density are considered as important factor concerning the permeability. Data acquisition of the properties of fracture such as aperture and density is so difficult and has uncertainty. We also cannot know the fracture characteristics through the in-situ tests. We usually obtain the fracture information from a ultrasonic scan logging or borehole television indirectly. Using the deduced results, we can make the fracture system and simulate the groundwater flow and solute transport in the crystalline rock. This study aimed to analyze the correlation between the properties of fracture and hydraulic conductivities obtained at the same interval. The properties of fracture are examined by acoustic televiwer and hydraulic conductivities are obtained by constant Pressure injection test. The distributioin of fracture width and fracture frequency shows the log-normal probability plot. And, Results of correlation analysis explain that opened type fractures have proper relation with hydraulic conductivity. But, as though there are semi-opened type fractures or closed type fractures, those have the permeable structure.

• The Journal of Engineering Geology
• /
• v.27 no.4
• /
• pp.463-474
• /
• 2017

Heterogeneous background fractures of granite and sedimentary rocks in Gyeongju LILW (low-intermediate level radioactive waste) facility area have been characterized quantitatively by analyzing fracture parameters (orientation, intensity, and size). Surface geological survey, electrical resistivity survey, and acoustic televiewer log data were used to characterize the heterogeneity of background fractures. Bootstrap method was applied to represent spatial anisotropy of variably oriented background fractures in the study area. As a result, the fracture intensity was correlated to the inverse distance from the faults weighted by nearest fault size and the mean value of electrical resistivity and the average volumetric fracture intensity ($P_{32}$) was estimated as $3.1m^2/m^3$. Size (or equivalent radius) of the background fractures ranged from 1.5 m to 86 m and followed to power-law distribution based on the fractal property of fracture size, using fractures measured on underground silos and identified surface faults.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.17-24
• /
• 2001

Several underground cavities were found during construction of a road tunnel in 600m length . The area belong to Whasoon coalfield where extensive ground subsidences have occurred. It is necessary to find other underground cavities which might be located just near the road tunnel for safety, The field surveys and laboratory tests were conducted such as surface geological survey(672m), surface reflection seismic exploration(399m), drilling test(3 NX holes), 9 laboratory tests for rocks, 3 boreholes televiewer tests, reflection seismic exploration in tunnel(2, 342m). To estimate the effects of underground cavities on the road tunnel, 3 geological section were analysed with FLAC-2D modeling. The effects of the ground reinforcement were also analysed.

• The Journal of Engineering Geology
• /
• v.17 no.4
• /
• pp.623-631
• /
• 2007

In this paper, dynamic elastic module of banded gneiss were calculated on the basis of SPS velocity logging data obtained from a geotechnical test-hole in Pungsan-dong, Hanam, Gyeonggi Province, Korea. This study mainly focuses on the velocity analysis, Q factor calculation relative to attenuation factor, and generation of crack information and its relation with seismic velocity. As a result, P-wave and S-wave velocity of fresh hard rock was 5,559m/s and 3,063m/s, respectively, with Poisson's ratio being 0.28. With these results, dynamic modules were prepared, and crack information analyzed by acoustic televiewer was incorporated to identify the correlation among and between delay of first arrival by crack amplitude ratio, and velocity. The results of this study revealed that the analyzed logging hole mainly consisted of micro crack and a number of cracks and the size of crack aperture, functioned as a variable to seismic velocity in the micro crack area of this type of hard rock.

• Korean journal of communication and information
• /
• v.46
• /
• pp.420-448
• /
• 2009

This paper aims at advancing the understanding of human communication by reflecting the role of the consciousness of time in television communication. As the past, the present and the future are not independent realities, but co-exist in the human consciousness, the 'experience' and the 'expectation' are used as two essential conceptual tools which explain the mechanism of operation of the consciousness of time. The man anticipates the future based on the experience updated in the present, and chooses a present action and feels an emotion according to the expectation. The consciousness of time is extended to the symbolic instrument of time and the dominant vision of the world in the process of the socialization. The role of the consciousness of time in television communication is analyzed in both genres of information and fiction based on the media characteristics of television. The information and the fiction genres oppose to each other according to their relationships to the reality, but it turned out that their effects of communication such as enjoyment and novelty depends in common on the way of using the televiewer's consciousness of time.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1727-1734
• /
• 2008

After the final closure of sea dyke, seepage behaviour of embankment is highly changed by variation of water head different between tide wave and controlled water level at fresh lake. Especially, the seepage behaviour of bottom protection layer of final closure section is more important factor for structural and functional stability of sea dyke, because of the bottom protection layer of final closure section is penetrated sea side to fresh lake. Even though bottom protection layer was filled with dredged fine sand, it has a high permeability. In this paper, mainly described about the seepage velocity and borehole image of bottom protection layer filled with dredged sand after final closure. Various in-situ tests such as BIPS (Borehole Image Processing System) and ABI (Acoustic Borehole Imager) survey, wave velocity measuring, and color tracer survey were conducted to evaluate the seepage behavior of bottom protection layer. Based on the in-situ tests, the bottom protection layer of final closure section was almost filled with dredged sand which is slightly coarse grain sand and there have sea water flow by water head different between tide wave and controlled water level at fresh lake. Also, comply with tracer survey results, the sea water flow path was not exist or generated in the bottom protection layer. However, because of this result not only short term survey but also just one test borehole survey results, additional long term and other borehole tests are needed.

• Tunnel and Underground Space
• /
• v.18 no.1
• /
• pp.80-89
• /
• 2008

The influence of in-situ rock stress on the stability of an underground rock structure increases as the construction depth become deeper and the scale of a rock structure become larger. In general, hydraulic fracturing stress measurement has been performed in the surface boreholes of the target area at the design stage of an underground structure. However, for some areas where the high horizontal stresses were observed or where the overstressed conditions caused by topographical and geological factors are expected, it is desirable to conduct additional in-situ stress measurement in the underground construction site to obtain more detailed stress information for ensuring the stability of a rock structure and the propriety of current design. The study area was a construction site for the additional underground oil storage facility located in the south-east part of OO city, Jeollanam-do. Previous detailed site investigation prior to the design of underground structures revealed that the excessive horizontal stress field with the horizontal stress ratio(K) greater than 3.0 was observed in the construction area. In this study, a total of 13 hydraulic fracturing stress measurements was conducted in two boreholes drill from the two water tunnel sites in the study area. The investigation zone was from 180 m to 300 m in depth from the surface and all of the fracture tracing works were carried out by acoustic televiewer scanning. For some testing intervals at more than 200 m ind depth from surface, the high horizontal stress components the horizontal stress ratio(K) greater than 2.50 were observed. And the overall investigation results showed a good agreement with the previously performed test.

• Economic and Environmental Geology
• /
• v.40 no.1 s.182
• /
• pp.87-101
• /
• 2007

A variety of informations obtained from satellite image, digital elevation relief map (DEM), borehole logging, televiewer, geophysical prospecting, etc were synthetically analyzed to investigate subsurface geological and structural characteristics and to evaluate geohazard pertinent to fault-damage in the Busan metropolitan city. It is revealed that the geology is composed of the Cretaceous andesitic$\sim$dacitic volcanics, gabbro, and granitoid and that at least three major faults including the Dongrae fault are developed in the study area. Based on characteristics of topography, fault-fractured zone, and isobath maps of the Quaternary sediments and weathered residuals of the basement, the Dongrae fault is decreased in its width and fracturing intensity of damaged zone from south toward north, and the fault is segmented around the area between the Seomyeon and Yangieong junctions. Meanwhile, we drew a geohazard sectional map using the five major parameters that significantly suggest damage intensity of basement by fault, i.e. distance from fault core, TCR, RQD, uniaxial rock strength, and seismic velocity of S wave. The map is evaluated as a suitable method to express the geological and structural characteristics and fault-damaged intensity of basement in the study area. It is, thus, concluded that the proposed method can contribute to complement and amplify the capability of the present evaluation system of rock mass.