• 자원환경지질
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• 제31권6호
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• pp.527-534
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• 1998

Excavation of underground openings changes stress distribution around the opening. The survey of this disturbed zone in excavation is very important to design and construct underground facilities, such as tunnel, gas and oil storage, power plant and disposal site of high- and low-level radioactive wastes. This paper presents a zoning of rock masses with tunnel excavation using PS logging. Compressional and shear wave velocities are measured in boreholes drilled in the tunnel wall, which was constructed with blasting and/or machine excavation. The disturbed zone in excavation can be estimated by comparing PS logging data with a tomographic image of compressional wave velocity and compressional and shear wave velocities of core samples. In the side wall of tunnel, the disturbed zone reaches 1.5 m and 1.0 m in thickness for blocks of blasting and machine excavations, respectively. In the roof of tunnel, however, the disturbed zone is 1.0 m and 0.75 m thick for the two blocks. These results show that the width of the disturbed zone is larger in the side wall of tunnel than in the roof, and 1.3 to 1.5 times larger for the blasting excavation than for the machine excavation.

• 터널과지하공간
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• 제4권2호
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• pp.102-118
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• 1994

Thermomechanical analysis is conducted on the radioactive repository in deep rock mass considering the in-situ stress, excavation and thermal loading of a radioactive waste. Thermomechanical properties of a discontinuous rock mass are estimated by a theoretical method so called sequential analysis. Using the estimated properties as input for finite element analysis, the influence on temperature distribution and thermal stress is analyzed within the scope of 2-dimensional steady state and transient heat transfer and coupled thermal elastic plastic behaviour. Granitic rock mass is taken for this analysis. The analysis is done for two different rock mass conditions, i.e. continuous-homogeneous and highly jointed conditions, for the purpose of comparison. In the case of steady state, the extent of disturbed zone around the storage tunnel due to the heat production of the spent-fuel canister varies depending on the thermomechanical properties of the rock mass. In the case of transient analyses, the response of the jointed rock mass to the thermal loading after radioactive waste disposal varies significantly with time, resulting in dramatic changes in the both size and location of disturbed zone.

• 산업기술연구
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• 제24권B호
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• pp.3-17
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• 2004

Overbreak, underbreak and range of disturbed rock zone (DRZ) are the most important factors in evaluating the results of tunnel blasting. These factors, which depend on the discontinuities in rock mass, the blasting patterns and drilling conditions, have been studied. The range of DRZ can be estimated by relationships between vibration velocity and associated tensile stress. A new computerized rocket jumbo drill has been adopted to reduce overbreak based on the analysis of drilling accuracy. In-situ blasting tests were also performed by varying initiating systems. Overbreak can be reduce from 34.5cm to 20cm. The range of DRZ is 0.2m with stoping holes and 0.4m with wall holes respectively. In addition, some methods to reduce DRZ have been presented in this study.

• 한국지반공학회논문집
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• 제18권5호
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• pp.99-108
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• 2002

본 연구에서는 탄성, 탄소성 및 실험을 통해 유도된 비선형-취성-소성 모델을 지하 심부 원형터널의 경우에 적용하여 각 모델에 따른 특성과 추정되는 응력재분배 및 응력교란 범위를 비교하였다. 현지 초기응력의 크기와 주응력차가 커질수록 파괴영 역이 파괴되지 않은 영역에 미치는 응력재분배와 교란의 영향이 증가되기 때문에, 탄소성 또는 탄성 해석의 경우보다 비선형-취성-소성 해석결과에서 응력재분배 및 교란영역, 주응력차와 변위가 더 크게 발생하였다. 따라서 현지 응력 수준과 현지 주응력차가 클 경우, 비선형-취성-소성 해석에 의해 손상영 역의 범위가 더 크게 발생할 것으로 예측되므로 손상해석의 필요성이 증대될 것으로 판단되었다.

• 터널과지하공간
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• 제18권2호
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• pp.91-97
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• 2008

본 고에서는 공동굴착에 따른 주변 영향영역 암반의 투수 특성 변화를 간접적 방법이 아닌 직접적으로 측정 가능한 현장수리시험장비를 소개하고 국내 지하연구시설(URL) 현장실험에 적용한 결과를 수록하였다. 굴착공동 주변 수리학적 EDZ의 투수계수 측정의 정밀도 향상을 위해서는 잘 설계된 시험장비와 함께 시험결과를 분석 평가하는 기술이 통합된 시스템 개발이 필요할 것으로 생각된다. 이를 통해 지하수면 아래 건설되는 공동의 안정성 평가, 방배수 시스템 및 그라우팅 설계의 신뢰도 향상에 기여할 수 있을 것으로 기대된다.

• 화약ㆍ발파
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• 제25권1호
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• pp.15-29
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• 2007

고준위폐기물 처분연구를 위해 원자력연구원 내에 건설된 지하처분연구시설(KURT)에서 발파에 의해 발생하는 암반 손상대의 규모를 평가하기 위한 실험실 시험과 현장시험이 실시되었다. 실험실 시험결과 및 현장 시험결과 터널 벽면에서의 손상대는 1m 이상까지 발생하는 것으로 나타났다. 발파의 영향을 받은 구간($0{\sim}2(m)$)에서 회수된 암석 코아의 RQD 값은 발파영향을 받지 않은 구간에 비해 17% 낮게 나타났으며, 발파 후 암반 변형계수는 발파 전에 비해 약 40% 감소되는 것으로 나타났다.

• 화약ㆍ발파
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• 제24권1호
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• pp.1-8
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• 2006

최근 대부분의 석회석 광산은 환경문제 등으로 인하여 노천채광에서 지하채굴로 전환되었다. 그 결과 노천채광과 같은 생산성을 유지하기 위해 갱도가 대형화되고 있다. 이에 따라 갱도 및 광주의 규모 그리고 굴착방법 등에서 많은 문제가 발생하고 있다. 본 연구는 두 갱도의 동시 발파 혹은 단일갱도 내에서 좌운반갱도와 사갱을 동시 발파, 두 갱도를 다단 발파 그리고 각각의 갱도를 단독 발파하여 굴착했을 때의 발파진동을 계측하여 각각의 굴착방법에 따라 발파진동식을 산출하여 노모그램 분석과 암반손상권 분석을 실시하였다.

• 방사성폐기물학회지
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• 제9권2호
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• pp.99-105
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• 2011

중저준위 방사성폐기물 처분장의 안전성 평가를 위하여 지하 사일로와 그 주변의 굴착손상영 역 (EDZ) 및 단열암반을 고려한 지하수유동해석과 핵종이동해석의 통합모델을 개발하였다. 사일로를 다중방벽개념으로 고려하여 사일로를 구성하는 3개의 특성지역 (waste, buffer, concrete)으로 구분하여 해석하였고, EDZ는 사일로 주변과 건설운영 터널 주변의 손상영역을 고려하였다. 단열암반의 불균일성은 분리단열 (discrete fractures)로 부터 해석된 불균일한 지하수 유속계로 도출하였고, 그 결과를 핵종의 이동경로를 모사하는데 사용하였다. 현 모델은 핵종누출에 따른 사일로 배치의 최적화와 안전성의 정량화를 도출하는데 사용가능하다.

• 지구물리와물리탐사
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• 제7권1호
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• pp.62-69
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• 2004

The objective of this study is to estimate the distribution of a zone disturbed by excavation (EDZ) around tunnels that have been excavated at about 500 m depth in pre-Tertiary hard sedimentary rock. One of the most important tasks is to evaluate changes in the dynamic stability and permeability of the rock around the tunnels, by investigating the properties of the rock after the excavation. We performed resistivity and acoustic tomography using two boreholes, 5 m in length, drilled horizontally from the wall of a tunnel in pre-Tertiary hard conglomerate. By these methods, we detected a low-resistivity and low-velocity zone 1 m in thickness around the wall of the tunnel. The resulting profiles were verified by permeability and evaporation tests performed at the same boreholes. This anomalous zone matched a high-permeability zone caused by open fractures. Next, we performed resistivity monitoring along annular survey lines in a tunnel excavated in pre-Tertiary hard shale by a tunnel-boring machine (TBM). We detected anomalous zones in 2D resistivity profiles surrounding the tunnel. A low-resistivity zone 1 m in thickness was detected around the tunnel when one year had passed after the excavation. However, two years later, the resistivity around the tunnel had increased in a portion, about 30 cm in thickness, of this zone. To investigate this change, we studied the relationship between groundwater flow from the surroundings and evaporation from the wall around the tunnel. These features were verified by the relationship between the resistivity and porosity of rocks obtained by laboratory tests on core samples. Furthermore, the profiles matched well with highly permeable zones detected by permeability and evaporation tests at a horizontal borehole drilled near the survey line. We conclude that the anomalous zones in these profiles indicate the EDZ around the tunnel.

• 한국조경학회지
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• 제32권2호
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• pp.102-119
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• 2004

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Bokha stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into five types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. The major results of this study are as follows: 1) A pool connected to the main stream has a certain water depth (about 80 cm) and is disturbed at least 5 to 6 times a year. Although the pool has a somewhat bad water quality, it provides a habitat for various types of young fish. 2) A meander riffle is about 15 cm deep, the flow velocity in the region is about 75 cm/s. This region does not have large structures to which aquatic insects can attach, so it cannot be used as a spawning ground. 3) A rock type pool is about 60 cm deep, the flow velocity in the meander riffle is about 25 cm/s. In this region, many aquatic insects attached to large structures appear. Due to various riparian vegetation, the rock type pool is used as a habitat for aquatic insects. 4) A pool which is only connected to the main stream during floods has a bad water quality. Despite of its relatively small size, it has a high population density of aquatic insects. faculty.