Tunnels Under The Condition Of Full-length Bonded Anchor Effect Analysis And Numerical Simulation Based On Small Spacing

With the development of Expressway，tunnel construction become more and more，construction environments are getting more sophisticated，due to environmental constraints,spacing between tunnel two hole is also getting smaller and smaller，so while peopleconcerned about on the surrounding rock’s stability is also increasingly, so its reasonableand effective means of support is increasingly important, full-length bonded anchor rods asone of the most frequently used in tunnel support, for the maintenance of stability ofsurrounding rock of tunnel play an irreplaceable role.This small spacing tunnels under construction for engineering based in predecessorson the basis of theoretical study and experimental research, summarized the effect oftunnel surrounding rock stability of five major internal and four external factors, and on theelaboration of a detailed；Summarized five common failure modes of the tunnel, andsummarized four criterion judgments of surrounding rock instability；Through the studyconcluded that the existing mechanism of bolt anchorage and carried out a detailed studyon the mechanism of full-length bonded anchor rods，drawn anchorage axial force offull-length bonded anchor primarily provided by the bonding force between through simplebolt body and bonding materials bonded and bond and surrounding rock mass of material;But their resistance arising from the dislocation between its rock shearing stress capacity isprovided through anchor’s own mechanical properties of materials.Finally this article through research several methods of solving geotechnicalengineering problems used currently，comparative analysis of existing research on solvingthe problems of tunnel support means，finally chose to FLAC3D finite difference programto study the means, different layout parts, different ring to bolt to the spacing and differentlength in different conditions, such as, design a28different conditions respectively tonumerical simulation，and28under different conditions of bolt support effect analysis ofnumerical simulation results, draw in Qishan tunnel, under the condition of V-levelsurrounding rock of reasonable layout of anchor parts, reasonable space betweenreasonable loop to anchor and bolt length.