Optimal reinforcement of slope adjacent to tunnel in a jointed rock mass

초록

l. INTRODUCTION When we excavate the rock slope to construct a road or other structures adjacent to the existing railroad tunnel, we should solve not only the slope stability problems but also the tunnel safety problems, especially, in a jointed rocks. Sliding failure of slope could be occurred through the existing tunnel. Therefore, the safety of cut slope and existing tunnel should be analyzed simultaneously under the consideration of the joint condition of rock mass, slope status. and slope reinforcement method. Therefore, it is very difficult to find any optimal reinforcement method, which can secure the safety of both slope and tunnel simultaneously. Very few studies could be found. which are mostly limited to pertaining to homogeneous ground. In the jointed ground, therefore, construction is often undertaken based on the judgment of experienced site engineer. In this study, the optimal slope reinforcement time without any influence on the safety of adjacent tunnel in jointed rocks was experimentally studied. Large scale model tests were performed in the biaxial test facility (3.lm X 3.lm x 0.50m (width X height X length) , in which test ground with regular joints was simulated by concrete blocks and model tunnel in 1/10 scale (0.6 m in diameter) was built lip. Joint was varied in dips from vertical to horizontal (0°-90°), while the angle of excavated slope was changed 30° to 90°.