• Title/Summary/Keyword: 불연속면의 밀도

Search Result 34, Processing Time 0.012 seconds

Case study on application of discontinuity density as a characteristics factor of rock mass groundwater (암반지하수 특성 인자로서 불연속면 밀도 적용 사례 연구)

  • Ihm, Myeong Hyeok
    • The Journal of the Convergence on Culture Technology
    • /
    • v.10 no.5
    • /
    • pp.693-698
    • /
    • 2024
  • As there are various types of discontinuities developing along with various rock types, the orientation and density of each type of discontinuities were measured to analyze the behavior of groundwater within the rock mass. Among the orientations of discontinuities, the strike was measured in azimuth and expressed as a discontinuity trajectory, and the density of discontinuities was quantified as the sum of the lengths of discontinuities developed per unit area. The overall discontinuity trajectory in the study area is predominantly in the northeast direction, the north-south and east-west directions are dominant in the igneous rock distribution area, and the east-west and northeast directions are dominant in the sedimentary rock distribution area. Among the types of discontinuities, they show discontinuity trajectories similar to the northeast direction, which is the dominant orientation of stratum boundaries, stratification, and foliation. The discontinuity density ranges from 0.1 m-1 to 1,000 m-1. The density distribution of discontinuities was expressed in the form of discontinuity contour diagrams. As a result, the crushed rock near Demiseam in the southern and southwestern part of the study area, the igneous rock area around Maryeong-myeon, the igneous rock area near Yongdam Dam in the northeast, and the igneous rock area near Unilam and Banilam in the northwest showed the highest density of discontinuities at over 100m-1., the sedimentary rock area near Maisan Mountain showed relatively low values. It suggests that the results of geophysical exploration and drilling survey data in the existing study area, as well as the geological structure and density and trajectory of discontinuities, may be important factors in the behavior of groundwater in rock mass in the future.

Study on Density Discontinuous Layers of the Kunsan Basin in the Yellow Sea Using Satellite Altimetry Gravity Data (인공위성 해면고도계 중력자료를 이용한 황해 군산분지의 밀도 불연속면에 대한 연구)

  • Kim, Kyong-O;Oh, Jae-Ho
    • Economic and Environmental Geology
    • /
    • v.40 no.6
    • /
    • pp.751-759
    • /
    • 2007
  • To better understand the subsurface geological structure of the Kunsan Basin in the Yellow Sea, the mean depths of the density discontinuous layers (DDLs) of the Kunsan Basin were calculated by power spectrum analysis using satellite altimetry gravity data. The calculated mean depths of DDLs were -1.1km, -3.4km, -9.1km and -31.0km. The mean depth of -1.1km DDL was interpreted as regional unconformity shown in about 1 second in two way travel time (TWTT) in the seismic reflection profiles, and the mean depth of -3.4km DDL was also interpreted as top of the acoustic basement in the seismic reflection profiles. Comparing with well data, seismic reflection profiles and regional geology in the study area, the mean depth of -9.1km DDL was interpreted as top of the igneous origin basement. This means that the acoustic basement of the study area is composed mainly of sediments which are disregarded in previous study. The mean depth of -31.0km DDL was interpreted as the Moho discontinuity because this mean depth is similar to one of the normal continental crust thickness. The detection of top of the igneous origin basement suggests that oil gas potential analysis in Kunsan Basin needs to be extended to the deeper part of sediments (acoustic basement).

Sensitivity Analyses of Three-Dimensional Discrete Fracture Network Modeling of Rock Mass (암반의 3차원 불연속균열망(DFN)에 관한 연구 및 민감도분석)

  • Park, Jung Chan;Park, Seung Hun;Kim, Ha Yung;Kim, Geon-Young;Kwon, Sangki
    • Tunnel and Underground Space
    • /
    • v.25 no.4
    • /
    • pp.341-358
    • /
    • 2015
  • This study analyzes the relationship between parameters of the discontinuity in Discrete Fracture Network model such as fracture intensity, fracture orientation, fracture size, fracture shape etc. In this paper, FracMan code was used to model and analyze 3D DFN. A sensitivity analysis was performed in order to analyze the relationship between linear fracture intensity measure ($P_{10}$) and parameters of the discontinuity in $100m{\times}100m{\times}100m$ model area. As a result the sensitivity analysis showed that key parameters affecting fracture intensity are fracture orientation (Trend / Plunge). Conversion factor($C_{13}$) for $P_{10}$, to calculate volumetric fracture intensity measure ($P_{32}$), is derived in case of vertical well and horizontal well when trend is $10^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$, $150^{\circ}$, $180^{\circ}$ (7cases) and plunge is $5^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$, $85^{\circ}$ (7cases). It is expected that this paper can be used effectively for modeling and understanding DFN model.

석회암지역에서 불연속면의 물리검층반응

  • Kim, Yeong-Hwa;Yang, Yeong-Geun;Kim, Jung-Yeol;Kim, Yu-Seong
    • Journal of the Korean Geophysical Society
    • /
    • v.4 no.2
    • /
    • pp.95-102
    • /
    • 2001
  • As a basic study of characterizing fracture condition in bore hole, conventional geophysical well log data consisting of sonic, gamma-gamma and resistivity logs were compared with geological core log and acousic televiewer log in limestone geology. Discontinuities shown on the acoustic televiewer log and the core log show fairly good correlation. The conventional Geophysical log is also shown to bi effective in locating discontinities in limestone geology; sonic log shows the best result and resistivity shows the worst. Particularly, the combination method of density and sonic logs is shown to be the most effective in delineating discontinuities.

  • PDF

Determination of Equivalent Hydraulic Conductivity of Rock Mass Using Three-Dimensional Discontinuity Network (삼차원 불연속면 연결망을 이용한 암반의 등가수리전도도 결정에 대한 연구)

  • 방상혁;전석원;최종근
    • Tunnel and Underground Space
    • /
    • v.13 no.1
    • /
    • pp.52-63
    • /
    • 2003
  • Discontinuities such as faults, fractures and joints in rock mass play the dominant role in the mechanical and hydraulic properties of the rock mass. The key factors that influence on the flow of groundwater are hydraulic and geometric characteristics of discontinuities and their connectivity. In this study, a program that analyzes groundwater flow in the 3D discontinuity network was developed on the assumption that the discontinuity characteristics such as density, trace length, orientation and aperture have particular distribution functions. This program generates discontinuities in a three-dimensional space and analyzes their connectivity and groundwater flow. Due to the limited computing capacity In this study, REV was not exactly determined, but it was inferred to be greater than 25$\times$25$\times$25 ㎥. By calculating the extent of aperture that influences on the groundwater flow, it was found that the discontinuities with the aperture smaller than 30% of the mean aperture had little influence on the groundwater flow. In addition, there was little difference in the equivalent hydraulic conductivity for the the two cases when considering and not considering the boundary effect. It was because the groundwater flow was mostly influenced by the discontinuities with large aperture. Among the parameters considered in this study, the length, aperture, and orientation of discontinuities had the greatest influence on the equivalent hydraulic conductivity of rock mass in their order. In case of existence of a fault in rock mass, elements of the equivalent hydraulic conductivity tensor parallel to the fault fairly increased in their magnitude but those perpendicular to the fault were increased in a very small amount at the first stage and then converged.

A Study on the Gravity Anomaly of Okcheon Group based on the Gravity Measurement around Chung Lake (충주호 주변의 중력 측정에 의한 옥천계의 중력이상 연구)

  • Park, Jong-Oh;Song, Moo-Young
    • Journal of the Korean earth science society
    • /
    • v.32 no.1
    • /
    • pp.12-20
    • /
    • 2011
  • The gravity measurement was conducted at 256 stations around Chungju Lake to study subsurface geological distributions and subterranean mass discontinuities by the results of gravity anomaly in Metamorphic Complex, Okcheon Group, Great Limestone Group of Choson Supergroup, and Cretaceous biotite granites. Okcheon Group showed a high Bouguer gravity anomaly while Great Limestone Group of Choson Supergroup relatively a low anomaly. The mean depth of subterranean mass discontinuities is about 2.0 km and downward along the Suchangri Formation from the Hwanggangri and Moonjuri formations. In general, Okcheon Group appeared shallower than the depth of Great Limestone Group of Choson Supergroup when imaging the subterranean mass discontinuities from the Bouguer gravity anomaly.

Discontinuity Analysis Using Well Log Methods from a Borehole-PABH1 in the Pungam Sedimentary Basin (풍암퇴적분지 내 시추공 PABH1에서 불연속면에 대한 물리검층방법의 적용)

  • 김영화;장승익;김중열;현혜자
    • The Journal of Engineering Geology
    • /
    • v.8 no.3
    • /
    • pp.261-273
    • /
    • 1998
  • Multiple well log analysis technique consisting of geophysical well log and geological core log has been made to analysis the discontinuities of a test borehole-PABH1 located in Pungam sedimentary basin, Sosok, Hongchon-gun, Kangwon Province. Well log methods consist of normal resistivity log, focussed log, single point resistance log, SP log, gamma log, natural gamma log as well as acoustic televiewer log and borehole television log. Core scanning technique was used as an aid for geological core log. The analysis was made by comparing firstly the televiewer and core discontinuities, and then the results from conventional geophysical log analysis were compared to those from core log and acoustic televiewer log. Fractures deduced from the acoustic televiewer log coincide well with discontinuities shown on the core and conventional geophysical logs. Particularly close coincidence could be observed between fractures derived from acoustic televiewer and conventional geophysical log analysis. It has been noted that the geophysical logs such as, caliper, resistivity, density and high resolution gamma gamma curves are effective in delineating the fractures. For example the ratio between density and resistivity (BRD/SHN) provides also an alternative indicator for discerning the fracture condition in the study area.

  • PDF

Parameter Effect on Elastic Modulus of Discontinuity Rock-mass Based on Homogenization Method (균질화 이론에 근거한 불연속성 암반의 탄성계수에 영향을 미치는 불연속면의 조사 인자에 관한 연구)

  • Baek, Yong
    • Journal of the Korean Geotechnical Society
    • /
    • v.16 no.4
    • /
    • pp.63-70
    • /
    • 2000
  • The quantitative analyses and the mechanical interpretation of discontinuity planes are the most important factor for the study of strength and deformation properties of rock masses containing discontinuity planes. However, the relationship between the factors investigated in the field and the actual mechanical properties of discontinuity planes is not fully understood. The main purpose of this study is to investigate the effects of density, length, and spacing of joints on elastic modulus of rock masses as these values vary. A new parameter which has a direct relation with the elastic modulus of discontinuity planes is also preposed in this study. The combination of finite element methods and homogenization methods has been used for the numerical analyses of a uintcell with discontinuity planes, which is generated using random-number generation methods. The elastic modulus of the discontinuity plane is found from the numerical analyses. The final results propose not only the relation between the investigation parameters of discontinuity planes and the elastic modulus of rock masses but also a new parameter, an effect area ratio having a linear relation with the elastic modulus of rock masses.

  • PDF

Estimation of Micro-discontinuity Distribution Using Scanline Survey in Granites (조사선을 이용한 화강암의 미세 불연속면 분포성상 평가)

  • 이상은;조상호;양형식;박홍민
    • Tunnel and Underground Space
    • /
    • v.9 no.4
    • /
    • pp.364-372
    • /
    • 1999
  • In this paper, mechanical characteristics of micro-defects in granitic rock was studied. Crack spacing and length were investigated by scanline survey in specimen of granite. To estimate the direction and distribution of potential microcrack in granite, thin sections were made for three direction of Rift, Grain and Hardway axis of the rock specimen. The density and length of microcrack were investigated quantitatively. Three directions of microcracks are comparatively perpendicular. Crack density varies as direction differs, but crack length doesn't show influence of direction.

  • PDF

지반조사에 활용되는 시추공 및 여타 물리탐사 기법

  • 임해룡
    • 한국터널공학회:학술대회논문집
    • /
    • 2005.04a
    • /
    • pp.317-331
    • /
    • 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

  • PDF