Horizontal Rock Areas, The Rock Stability Study

Based on analyzing and collecting predecessors' materials, Xin'yaogao tunnel was chosen as an example, destruction type and mechanism of the tunnel adjacent formation in horizontally stratum area was studied in the paper. The adjacent formation was classified by the classification system of adjacent formation in horizontally stratum area which was established through the method of fuzzy comprehensive assessment. The tunnel excavation mechanics behavior of the banding rocks was simulated by the ANSYS general finite element computation software.Firstly, the destruction type and mechanism of tunnel adjacent formation in horizontally stratum area were analyzed in the paper, the main effect factors of stability and distorted destruction characteristics of tunnel adjacent formation were also summarized. According to the five basic classification standard such as complete structure, the block crack structure, the fragmentation structure, the banding structure and the scattering structure, the structure type in horizontally stratum area was illustrated and the conclusion that banding structure was the main structure was also brought forth.Secondly, considering the indefinite relation of the adjacent formation classification and evaluation factors the fuzzy message classification method of tunnel adjacent formation was established with fuzzy mathematics theory and method. The stability of Xin'yaogao tunnel adjacent formation was evaluated by the classification method. It turned out that the method was feasible in evaluating the type of the adjacent formation of the horizontally stratum area through the stability confirmation of tunnel adjacent formation.Finally, the tunnel excavation mechanics behavior of the banding rock body was simulated by using the ANSYS. On the basis of simulation with the plane plastic finite element, the adjacent formation stress distributed in the construction process was discussed which provided with reference to initial design and construction, dispelled the danger in construction process in order to prevent before they occur, and has significance in guiding the design and construction of tunnel.