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Research Article

Estimating the Failure Time of Rock Slopes through Monitoring the Behavior of Analogue Models

물리모형 거동 감시자료 분석을 통한 암반 사면의 파괴시간 추정에 관한 연구

Young-Hwan Noh1
,
Jeong-Gi Um2*
노 영환1
,
엄 정기2*
1Deputy Manager, Geotechnics Department, Woorieng Architecture and Consultants Co., Ltd.
2Professor, Department of Energy Resources Engineering, Pukyong National University
1(주)우리이엔지 지반부 차장
2부경대학교 에너지자원공학과 교수
*Corresponding Author
31 December 2024. pp. 595-607
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Abstract

We conducted failure tests on a cement mortar analogue slope under various conditions, including varying the joint roughness and infill material thickness and using constant hydraulic head increments or a static hydraulic head. The cement mortar model material was evaluated for its mechanical similarity to intact rock, providing a controlled analogue for studying failure mechanisms. An electronic probe and data logger provided data for slope behavior analysis and failure time estimation. Failure time was estimated using the inverse velocity, log(time)-log(velocity), log(velocity)-log(acceleration), and nonlinear least squares methods. The sliding surface transitioned from linear second-order to exponential third-order creep as the hydraulic head increased at a constant rate in a tension crack. Greater joint roughness and thicker infill prolonged the exponential creep phase. In addition, greater roughness and thinner infill corresponded to a greater hydraulic head at failure. Under a static hydraulic head applied to the tension crack, the analogue slope exhibited exponential creep failure due to the weight of the material and the static hydraulic head, even before reaching an equilibrium state. The nonlinear least squares method provided the most accurate estimates of failure time. The log(time)-log(velocity) and log(velocity)-log(acceleration) methods also produced estimates close to observed values, while the inverse velocity method was less accurate. Overall, all methods except the inverse velocity method are suitable for analyzing rock slope behavior and predicting failure time.

Keywords
rock slope
analogue model
displacement monitoring
failure time

본 연구는 시멘트 모르타르로 제작한 모형사면에 대하여 재료의 상사성을 검토하고 절리면의 거칠기, 충전물의 두께, 정속도 수압증가 및 정수압 하중 등의 다양한 지질공학적 조건의 시나리오를 고려하여 모형사면의 파괴실험을 수행하였다. 모형사면의 변위 거동은 전자프로브와 데이터로거에 의해 측정 ‧ 기록되었으며 사면의 거동분석 및 파괴시간 추정을 위한 입력자료로 사용되었다. 모형사면의 파괴시간 추정은 역속도법, 로그시간-로그속도법, 로그속도-로그가속도법, 비선형 최소자승법을 적용하였다. 모형사면에서 활동면의 거동은 인장균열에서 정속도로 수압 하중이 증가할 때 2차 크리프 형태의 선형에서 3차 크리프 형태의 지수형으로 전이가 일어나는데, 거칠기가 거칠어질수록 또는 충전물이 두꺼워질수록 지수형을 유지하는 시간이 길어진다. 파괴 시 수압 하중의 양은 거칠기가 증가할수록 또는 충전물의 두께가 감소할수록 증가한다. 모형사면은 인장균열에 정수압 하중을 가했을 때 한계평형 상태에 도달하지 못한 조건에서도 재료의 무게 및 정수압 하중에 의해 크리프 형태의 지수형 파괴거동이 나타났다. 물리모형에서 측정한 파괴시간은 시간-변위에 대한 비선형최소자승법을 적용하여 추정한 파괴시간과 가장 잘 일치하였다. 또한, 로그시간-로그속도법과 로그속도-로그가속도법도 측정치와 근접한 추정치를 도출하였으며 역속도법을 제외한 모든 방법론은 암반 사면의 거동 및 파괴시간 추정에 활용할 수 있을 것으로 평가되었다.

키워드
암반 사면
물리모형
변위 감시
파괴시간
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Information
  • Publisher :Korean Society of Engineering Geology
  • Publisher(Ko) :대한지질공학회
  • Journal Title :The Journal of Engineering Geology
  • Journal Title(Ko) :지질공학
  • Volume : 34
  • No :4
  • Pages :595-607
  • Received Date : 2024-11-27
  • Revised Date : 2024-12-14
  • Accepted Date : 2024-12-17
  • DOI :https://doi.org/10.9720/kseg.2024.4.595
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