• Geomechanics and Engineering
• /
• 제20권1호
• /
• pp.29-41
• /
• 2020

It is extremely important to obtain rock strength parameters for geological engineering. In this paper, the evolution of sandstone cohesion and internal friction angle with plastic shear strain was obtained by simulating the cyclic loading and unloading tests under different confining pressures using Particle Flow Code software. By which and combined with the micro-crack propagation process, the mesoscopic mechanism of parameter evolution was studied. The results show that with the increase of plastic shear strain, the sandstone cohesion decreases first and then tends to be stable, while the internal friction angle increases first, then decreases, and finally maintains unchanged. The evolution of sandstone shear strength parameters is closely related to the whole process of crack formation, propagation and coalescence. When the internal micro-cracks are less and distributed randomly and dispersedly, and the rock shear strength parameters (cohesion, internal friction angle) are considered to have not been fully mobilized. As the directional development of the internal micro-fractures as well as the gradual formation of macroscopic shear plane, the rock cohesion reduces continuously and the internal friction angle is in the rise stage. As the formation of the macroscopic shear plane, both the rock cohesion and internal friction angle continuously decrease to a certain residual level.

• 한국환경과학회지
• /
• 제11권9호
• /
• pp.857-863
• /
• 2002

The meteorological elements were measured to investigate cause of summertime ice formation at Unchiri, Gangwon Province. The cause of freezing at valley was conformed as adiabatic expansion theory, latent heat of evaporation, natural convective theory, cold air remain theory, and convective freezing theory according to former study. However nither theory produced a satisfactory explanation. This studying area is not valley but ridge, and underground water surface exists at below than freezing height. wintertime temperature drop and summertime cold air spouting were explain as natural convective theory, generation of water drop on the rock was explained as cooling theory by air expansion, and ice formation on the rock was explained as adiabatic expansion theory. In conclusion, formation of ice valley at Unchiri was formed by natural convective theory, adiabatic expansion theory, and latent heat of evaporation successively.

• 한국지반환경공학회 논문집
• /
• 제10권6호
• /
• pp.125-133
• /
• 2009

유체를 주입하여 암반을 파쇄하는 기술은 지열이나 석유 및 가스 등을 추출하는데 널리 사용되고 있는 방법이다. 본 기술을 적용 시 단일균열이 형성되면 이러한 에너지를 추출하는데 가장 이상적이다. 그러나 이러한 단일균열의 형성은 매우 드문 현상이며 분할된 형태의 균열생성이 흔한 현상이다. 이에 균열간 기계적 상호작용의 영향으로 설계변수에서도 단일균열을 가정하고 적용되었던 값과 차이를 보일 것으로 예상된다. 본 연구에서는 균열이 분할 생성되었을 경우 기계적인 상호작용을 고려할 수 있는 수치해석기법을 기존의 개발된 모델과 연계하여 설계변수인 길이, 균열폭, 그리고 압력을 계산하였다. 그 결과 균열의 형성은 이렇게 유체를 주입하여 암반을 파쇄 시 사용되는 설계변수에 상당한 영향을 끼치는 것으로 나타났다.

• 터널과지하공간
• /
• 제15권6호
• /
• pp.411-424
• /
• 2005

풍화작용은 심부에서 생성된 암석이 지표에서 파괴되고 변질되어 현재의 환경조건과 평형을 이루는 산물을 형성하는 과정이다. 본 연구에서는 국내에서 가장 분포면적이 넓은 화강암질암의 풍화단계별 시료를 채취하여 편광현미경관찰, X-선 회절분석, 전자현미경관찰, 화학분석, 물성시험등을 수행하였다. 실험결과에 의거하여 풍화에 의해 형성되는 2차광물, 특히 점토광물의 형성과정을 확인하였고, 풍화에 따른 암석의 공학적인 성질변화와 물성저하의 메카니즘을 규명하였다.

• Geomechanics and Engineering
• /
• 제21권3호
• /
• pp.259-268
• /
• 2020

The synthetic rock mass (SRM) were used to investigate the influence of specimen size on the mechanical properties of jointed rock mass. The SRM were established based on parallel bond model (PBM) and smooth joint model (SJM) and the scaled rock specimens were sampled in two SRMs considering three sampling locations. The research results show that the smaller the initial fracture density is, the greater the uniaxial compressive strength (UCS), elastic modulus (E) is when compared with the same sampling location. The mechanical properties of rock specimens obtained by different sampling methods in different SRMs have different scale effects. The strength of rock specimens with more new cracks is not necessarily less than that of rock specimens with fewer new cracks and the failure of rock is caused by the formation of macro-fracture surface.

• 화약ㆍ발파
• /
• 제9권2호
• /
• pp.19-30
• /
• 1991

The trend of Radio active waste disposal project is generally to choose The Rock Cavern type because it is the most safest and easy to get concent from The neighbor hood. On the Construction of rock Cavern for R -A. W.0 has to take care follows ; The first of all, to survey rock crack formation. 2nd, The Movement of Underground water. 3rd, Nuclear and Geochemical problems. 4th, to examine physical feature of rocks ets.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
• /
• pp.92-96
• /
• 2006

Borehole geophysical techniques were adopted for characterizing aquifer properties of crystalline rock formation in Bongmyong borehole test site, Kangwon National University. Specific fractures and/or fracture zones accompanying groundwater flow were delineated well by high resolution flowmeter and dilution measurements, and could be confirmed fromconventional well log methods. These geophysical techniques have been proved to be the most effective in aquifer characterization in crystalline rock formation.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
• /
• pp.47-50
• /
• 2003

We carried out rock pneumatic fracturing test which to increase groundwater yield by injection of highly pressured air in artificially under the surface every four borehole. The result of test performing shows that effect of increasing groundwater was not found in three testhole around igneous and metamorphic formation area, but we can realized that about 15 percent increased wateryield appeared in number P-5 test hole at sedimmentary rock formation.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1995년도 춘계학술발표회논문집(2)
• /
• pp.769-774
• /
• 1995

In this study, a transport model was developed in order to analyze and predict the transport behaviors of radionuclides mediated by pseudo-colloid in the fractured rock media. It was resulted that the transport of Pu-239 was faster than Ni-63 because pseudo-colloid formation constant of Pu-239 was greater than that of Ni-63. Also, the effect of pseudo-colloid formation on the transport of a radionuclide was shown to be very significant when the apparent pseudo colloid formation constant, $K_{ap}(m^{3}/kg)$, was greater than 100. Thus, it can be concluded that acceleration of radionuclide migration may be occurred because the pseudo-colloid formation of radionuclides increases the amount of mobile components in the solution and consequently decreases the amount of radionuclides adsorbed on the stationary solid medium.

• 암석학회지
• /
• 제27권2호
• /
• pp.85-96
• /
• 2018

옥천변성대의 북서부에 위치하는 충주 어래산지역은 신원생대 계명산층과 중생대 화성암류가 분포하고, 계명산층 내에 희토류 광화대가 보고된 바가 있다. 이 논문에서는 희토류 광체의 기원암과 그 분포 및 특성을 파악하기 위해 암상구분에 의한 상세한 지질도를 작성하고, 구성암류의 방사능 값을 측정하였다. 그 결과 신원생대 계명산층의 주요 암상은 변성이질암, 화강암질편마암, 함철규암, 변성심성산성암(호상형, 세립형, 함염기성형, 조립형), 변성화산산성암 등으로 구성되어 있고, 이를 관입하는 중생대 화성암류는 페그마타이트, 흑운모화강암, 반려암, 섬록암, 염기성 암맥 등으로 구분된다. 계명산층의 구성암류는 주로 동북동 방향의 대상분포를 보이고, 함염기성형 변성심성산성암의 분포는 이전 연구자에 의해 작성된 희토류 광체의 분포와 매우 유사하다. 그리고 중생대 흑운모화강암은 기존 연구결과와 달리 어래산지역의 전역에 광범위하게 분포한다. 또한 함염기성형 변성심성산성암은 연구지역의 구성암류 중에 가장 높은 방사능 값의 범위(852~1217 cps)와 평균값(1039 cps)을 보인다. 노두별 방사능 값의 최대 밀도를 보이는 분포영역은 또한 함염기성형 변성심성산성암의 분포 영역과 일치한다. 이는 함염기성형 변성심성산성암이 희토류 광체의 기원암일 가능성을 지시한다.