• Title/Summary/Keyword: engineering geology

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Analysis of Relationships Between Topography/Geology and Groundwater Yield Properties at Pohang using GIS (GIS를 이용한 포항시 지형 및 지질과 지하수 산출능력 간의 상관관계 분석)

  • Lee, Sa-Ro;Kim, Yong-Sung;Kim, Nam-Jin;Ahn, Kyoung-Hwan
    • Economic and Environmental Geology
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    • v.41 no.1
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    • pp.115-131
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    • 2008
  • The aim of this study is to analyze relationships between topography/geology which affects physically groundwater regime and groundwater yield properties in Pohang City using Geographic Information System (GIS). For the purpose, topographic factors such as ground elevation, ground elevation difference, ground slope, and ground regional slope, and hydrogeologic unit, and groundwater yield properties factors such as transmissivity, specific capacity, and well yield, were constructed to spatial data base. Then the relationships between topography, geology and groundwater yield properties were analyzed quantitatively using GIS overlay technique. As the results, ground-water yield of unconsolidated sediments and porous volcanic rocks is the highest among the hydrogeologic units of study area, and clastic sedimentary rock is the lowest. There are positive relationship between the elevation and elevation difference and the groundwater yield properties and negative relationship between the topographic slope and the groundwater yield properties.

Applicability of Resistivity Image Profiling to Geologic Survey in the Keoje-do Area (전기비저항 영상법에 의한 거제도의 지반조사)

  • Park, Sam Gyu;Kim, Hee Joon
    • Economic and Environmental Geology
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    • v.27 no.6
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    • pp.563-569
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    • 1994
  • Resistivity Image Profiling has been applied to a geological survey in the Keoje-do area. Survey lines are located near the KD-02 and KD-06 wells in the area, where we have already sampled all rock cores and carried out several kinds of geophysical logs. In each site a resistivity cross-section is obtained by inverting pole-pole apparent resistivities. Comparing the reconstructed resistivity section with the rock cores and logging data obtained in the well provides a detailed picture of subsurface geology. The geology of KD-02 site is composed of conglomerate, sandstone and shale with fractures. The reconstructed resistivity image is useful for assessing the grade of weathering of these rocks. The KD-06 site is mainly underlain by granitic rocks, and its fresh basement can be delineated by resistivities over $1000{\Omega}{\cdot}m$.

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Correlation between Engineering Properties of Rocks in Korea (한반도의 암종별 공학적 특성의 상관성 분석)

  • Kim Gyo-Won;Kim Su-Jeong
    • The Journal of Engineering Geology
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    • v.16 no.1 s.47
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    • pp.59-68
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    • 2006
  • About 6,000 rock properties obtained from laboratory tests are collected from various projects conducted in Korea Peninsular and the distribution of the properties such as uniaxial compressive strength, cohesion, kriction angle, tangential strength, Young's modulus, p-wave velocity and S-wave velocity are analysed and correlated each other. The empirical equations deduced with 84% of reliability would be useful for preliminary design of geo-structures.

Gravity Survey of the Subsurface Geology and Geologic Structure between Samcheog and Taebaek Area (중력탐사에 의한 삼척-태백간의 지하지질 및 지질구조 연구)

  • Min, Kyung Duck;Cho, Kwang Eun
    • Economic and Environmental Geology
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    • v.28 no.1
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    • pp.79-88
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    • 1995
  • The gravity measurment has been carried out at 48 gravity stations with intervals of 1.0~1.5 km along the survey line between Samcheog, Gosari and Taebaek to study subsurface geology and geologic structure in the northeastern part of the Ockchon zone. The Bouguer gravity anomaly values were obtained from the measured gravity values through the gravity corrections. The subsurface geology and geologic structure were interpreted quantitatively by means of the Fourier series method and Talwani method for 2.5 dimensional body. In the study area, the depth of Conrad discontinuity is about 10 km at Samcheog, northeastern end of the survey line, and it is increased rapidly to about 12.5 km at Miro, 15 km at Gosari and 15.5 km at Dongjeom, southwestern end of the survey line, respectively. The depth of the basement of the Ockchon zone exposed at Samcheog is increased smoothly to about 2 km at 5 km from Samcheog along the survey line, and is exposed again in the area between Singiry and Gosari. Beyond Gosari its depth is increased to about 1.7 km, and displaced 2.3 km downward by Osipcheon fault near Dogyeri and 0.5 km by Baeksan thrust near Cheolam, respectively. Many V-shaped low Bouguer gravity anomalies resulted from the fracture zone associated with faults imply the existence of Osipcheon fault and several inferred faults. The low Bouguer gravity anomaly zone between Tongdong and Dongjeom is caused by Jurassic gneissose granite. A local high Bouguer gravity anomaly at 35 km along the survey line from Samcheog is interpreted by the effect of iron deposit of high density existed at subsurface. The thickness of Great Limestone Group varies from 0.5 km to 1.4 km, that of Pyeongan Supergroup from 0.4 km to 0.9 km, and that of Yangdeog Group is about 0.3 km. The thickness of Jurassic gneissose granite varies from 1.5 to 3.0 km.

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Application of Multivariate Statistics and Geostatistical Techniques to Identify the Distribution Modes of the Co, Ni, As and Au-Ag ore in the Bou Azzer-East Deposits (Central Anti-Atlas Morocco)

  • Souiri, Muhammad;Aissa, Mohamed;Gois, Joaquim;Oulgour, Rachid;Mezougane, Hafid;El Azmi, Mohammed;Moussaid, Azizi
    • Economic and Environmental Geology
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    • v.53 no.4
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    • pp.363-381
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    • 2020
  • The polymetallic Co, Ni, Cu, As, Au, and Ag deposits of Bou Azzer East are located in the western part of the Bou Azzer inlier in the Central Anti Atlas, Morocco. Six stages of emplacement of the mineralization have been identified. Precious metals (native gold and electrum) are present in all stages of this deposit except the early nickeliferous stage. From the Statistical analysis of the Co, As, Ni, Au, and Ag contents of a set of 501 samples, shows that the Pearson correlation coefficient between As-Co elements (0.966) is the highest followed by that of the Au-Ag couple (0.506). Principal component analysis (PCA) and hierarchical ascending classification (HAC) of the grades show, that Ni is associated with the pair (As-Co) and Cu is rather related to the pair (Au-Ag). The kriging maps show that the highest values of the Co, As and Ni appear in the contact of the serpentinite with other facies, as for those of Au and Ag, in addition to anomalous zones concordant with those of Co, Ni and As, they show anomalies at the extreme South and North of the study area. The development of the anomalous Au and Ag zones is mainly along the N40-50°E and N145°E directions.