Surrounding of a rock tunnel contains various structural discontinuities which requires utilizing numerical tools with ability to solve both continuous and discontinuous domains in a rock mass. This paper presents a three-dimensional numerical manifold method (3-D NMM) in analyzing complete failure process of key blocks in a rock tunnel. Based on the developed 3-D NMM, a rock block falling from the side and roof of a horseshoe-shaped tunnel is studied. 12 discrete blocks are created, from which the most critical key blocks are found. The falling process of the key blocks detaching from the tunnel is simulated. The corresponding critical friction angle is also calculated.
The robustness of the developed method is verified through the rock tunnel stability analysis, which demonstrates the potential ability to analyze the interactive contact among complex blocks in the 3-D numerical manifold platform.
