• Journal of the Speleological Society of Korea
• /
• no.44
• /
• pp.3-16
• /
• 1995

동굴에는 석회동굴 그밖에 용암굴과 파식굴 등으로 구별되는데 그 대부분은 석회동굴이다. 석회동굴인 경우 이의 생성과정과 그 특성을 보면 다음과 같다. 지표면에 내린 빗물은 땅속에 스며들어가 지하수류를 이루어 투수층을 따라 흘러 빠져 들어간다. 이때 이 공동이 동굴이 되는데 공동의 천정면에서 떨어지는 물방울이 그 위 지층에서 석회암층을 스며 내릴 때에는 석회질이 용해된 물방울이 공동천정에서 고드름 모양으로 종유석을 발달시키거나 또는 공동바닥에 떨어져 석순을 성장시킨다. 이것이 석회동굴이다.(중략)

• Geophysics and Geophysical Exploration
• /
• v.12 no.1
• /
• pp.27-32
• /
• 2009

In this study, we examined the applicability of a 3D electrical resistivity technique for the probing of underground cavities at a field test site in a karst area in Yongweol-ri, Muan-gun, in the south-western part of the Korean peninsula. At the test site, where the ground has subsided in the past, underground cavities are commonly found in the limestone bedrock, which is overlain with alluvial deposits. The limestone cavities at the test site are mostly filled with groundwater and clay; hence, they show levels of electrical resistivity that are significantly lower than those of the surrounding host bedrock. The results of this study demonstrate that the zones of low resistivity correspond to the zones of the cavities identified in the boreholes at the site, and that our 3D electrical resistivity survey is a very effective tool for detecting and mapping underground cavities in a karst area.

• Tunnel and Underground Space
• /
• v.24 no.4
• /
• pp.255-274
• /
• 2014

The target of this study is large scale rock slope collapsed by around 7 pm on August, 2012, which is located at ${\bigcirc}{\bigcirc}$ limestone quarries of Gangneung city, Gangwondo. The slope prior to the collapse is formed as the height of about 200 m and the average inclination of $45^{\circ}$. The estimated amount of the collapse is about $1,500,000m^3$ with respect to the slope after the collapse. Geotechnical and field investigations such as boring, geophysical prospecting, surface geological survey, geological lineaments, borehole imaging, metric 3D imaging, experimental and field test, mining work by year, and daily rainfall were performed to find the cause of rock slope failure. Various analyzes using slope mass rating, stereonet projection, limit equilibrium method, continuum and non-continuum model were conducted to check of the stability of the slope. It is expected that the cause of slope failure from the results of various analysis and survey is due to the combined factors such as topography, rainfall, rock type and quality, discontinuities, geo-structural characteristics as the limestone cavity and fault zones, but the failure of slope in case of the analysis without the limestone cavity is not occurred. Safe factor of 0.66 was obtained from continuum analysis of the slope considering the limestone cavity, so the ultimate causes of slope failure is considered to be due to the influence of limestone cavity developed along fault zone.

• The Journal of the Petrological Society of Korea
• /
• v.16 no.2 s.48
• /
• pp.47-58
• /
• 2007

This study examines the distribution of basement rocks in Gyochon-ri, Muan-eup, Muan-gun, Jeonnam where ground subsidence occurred in June 2005, and traces corrosion of limestone. Mica schist and rhyolite are distributed in the surface of the study area, but thick limestone layer with large and small caverns are distributed underground. A horizon of limestone with maximum width of 300 m and 4 km of length was found along the detour which is in the north of pound subsidence. Such identification of limestone presence would be very useful to predict potential ground subsidence. Limestone in this area was disturbed by fold and fault due to severe shearing deformation. Small caverns were frequently found in anticline part of folds formed in limestone layer. Schists with different thicknesses were intercalated in the limestone with shearing deformation and consist of sheet silicate minerals (chlorite and mica) and quartz. In sections of weathered specimen, it is shown that biotite of schist part was altered into chlorite and corrosion of calcite around the schist followed. This suggest that ground water permeated between intercalated sheet silicate minerals and corrosion of limestone began. And small caverns were generated where active corrosion occurred. This study suggests that because of many reasons (for instance, reclamation of the Bulmu reservior and excess pumping), cavern water level was lowered and cave sediments were removed, and it caused ground subsidence to occur.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2008.10a
• /
• pp.167-172
• /
• 2008

A microgravity survey was applied for detecting and mapping karstic cavities over limestone area at Gaeun. The gravity data were collected at about 1, 100 stations by 4 m interval. The density distribution beneath the profiles was drawn by two dimensional inversion based on the minimum support stabilizing functional, which generated better focused images of density discontinuities. We also imaged three dimensional density distribution by growing body inversion. The density image showed that the cavities were dissolved, enlarged and connected into a cavity network system.

• 도로교통
• /
• s.96
• /
• pp.20-31
• /
• 2004

• Magazine of the Korean Society of Hazard Mitigation
• /
• v.3 no.1 s.8
• /
• pp.49-59
• /
• 2003

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11a
• /
• pp.1-20
• /
• 1999

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11a
• /
• pp.119-144
• /
• 1999

• 한국지구물리탐사학회:학술대회논문집
• /
• 2000.09a
• /
• pp.87-111
• /
• 2000

In this study, we describe the principle and result of geophysical techniques which are widely used in geotechnical survey. Also we discuss two case histories. One is discrimination of limestone cavity areas by resistivity, seismic tomography, televiewer, well logging, and the other is discrimination of coal by resistivity, electromagnetic method, resistivity tomography.