Abstract
Large scale model tests and numerical analyses were performed in order to investigate the stress distribution on the base of pillar during two-arch tunnel excavation in the regularly jointed rocks. It was observed that the stress was irregularly distributed on pillar and the angle of discontinuities seriously influenced on the stress distribution on the pillar base in the discontinuous rock mass. In the numerical analyses results, It was shown that the stress level of pillar was greatly changed depending on the excavation sequences of two-arch tunnel. It was also observed that stress distributed eccentrically at the pillar as well as at the base of pillar. It is necessary to consider this point for the design of two-arch tunnel.
불연속성 암반에 2-Arch 터널을 건설할 경우, 필러에 작용하는 응력분포 특성을 파악하기 위하여 대형 모형실험과 수치해석을 수행하였다. 분석결과, 불연속면이 존재하는 경우에는 필러에 작용하는 하중이 매우 불규칙적으로 발생하였으며, 불연속면 경사의 영향이 큰 것을 확인하였다. 수치해석 결과 필러부에는 굴착단계에 따라 위치별로 큰 응력 차이가 확인되었다. 주목할 점은 터널 굴착시 벽체뿐만 아니라 필러 기초부에도 큰 응력 차이가 발생하였다. 필러 설계시 이러한 응력편차 현상을 신중하게 고려할 필요가 있다.