The Journal of Engineering Geology (지질공학)

The Korean Society of Engineering Geology (대한지질공학회)
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Estimation to the Strength of Basalt in Jeju Island according to Rock Failure Criterions

암석의 파괴규준에 따른 제주도 현무암의 강도 산정

  • Nam, Jung-Man (Department of Civil and Environmental Engineering, Cheju National University) ;
  • Yun, Jung-Mann (Department of Civil Engineering, Ansan College of Technology) ;
  • Song, Young-Suk (Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources)
  • 남정만 (제주대학교 해양과학부) ;
  • 윤중만 (안산공과대학 건설계열) ;
  • 송영석 (한국지질자원연구원 지구환경연구본부)
  • Published : 2009.06.30
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Abstract

In this study, a series of triaxial tests on Jeju basalt were carried out and then rock strength parameters were estimated by the Mohr-Coulomb failure criterion and the Hoek-Brown failure criterion using the test results. The characteristics of both failure criterions were investigated through comparing the estimated rock strength parameters. As the result of the Mohr-Coulomb criterion, the cohesions and the internal friction angles are determined as 5.35 MPa and $50.25^{\circ}$ of Pyoseonri basalt, 16.99 MPa and $60.66^{\circ}$ of Trachy-basalt, and 2.33 MPa and $37.05^{\circ}$ of Scoria, respectively. The cohesions and internal friction angles were estimated by the Hoek-Brown failure criterion in the basis of the results of regression analysis. The cohesions and the internal friction angles are determined as 4.77 MPa and $52.47^{\circ}$ of Pyoseonri basalt, 14.69 MPa and $60.70^{\circ}$ of Trachy-basalt, and 2.22 MPa and $47.60^{\circ}$ of Scoria, respectively. As the result of comparison between the Mohr-Coulomb failure criterion and the failure envelope predicted by the Hoek-Brown criterion, the cohesion estimated by the Hoek-Brown criterion is usually lower than that obtained from the Mohr-Coulomb criterion, whereas the friction angle estimated by the Hoek-Brown criterion is higher than that obtained from the Mohr-Coulomb criterion.

본 연구에서는 제주도 현무암에 대한 삼축압축시험을 실시하고 암석의 Mohr-Coulomb파괴규준과 Hoek-Brown파괴규준을 적용하여 강도정수를 산정하였다. 그리고 각각의 파괴규준에 의해 산정된 강도정수를 비교검토하여 각각의 파괴규준에 대한 특성을 고찰하였다. 암석의 Mohr-Coulomb파괴규준을 적용한 결과 표선리 현무암의 경우 점착력은 5.35 MPa, 내부마찰각은 $50.25^{\circ}$이고, 조면암질 현무암의 경우 점착력은 16.99 MPa, 내부마찰각은 $60.66^{\circ}$이며, 스코리아의 경우 점착력은 2.33 MPa, 내부마찰각은 $37.05^{\circ}$이다. 암석의 Hoek-Brown의 파괴규준에 대한 회귀분석결과를 토대로 암석의 점착력과 내부마찰각을 선정할 수 있다. 표선리 현무암의 경우 점착력은 4.77 MPa, 내부마찰각은 $52.47^{\circ}$이고, 조면암질 현무암의 경우 점착력은 14.69 MPa, 내부마찰각은 $60.70^{\circ}$이며, 스코리아의 경우 점착력은 2.22 MPa, 내부마찰각은 $47.60^{\circ}$이다. 이상의 결과를 토대로 Mohr-Coulomb의 파괴포락선과 Hoek-Brown의 파괴규준으로부터 추정된 파괴포락선을 비교한 결과 Hoek-Brown의 파괴규준은 Mohr-Coulomb의 파괴규준보다 점착력은 대체로 낮게 평가되는 반면, 내부마찰각은 크게 평가되고 있다.

Keywords

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