Abstract：
In light of large tunnel deformation control, it′ s necessary to consider reinforcement of surrounding
rock, large stiffness support, moderate stress release, reasonable construction method and enhanced construction management and so on. Taking the large deformation control during construction of the Muzhailing extra-long tunnel as an example, an analysis and summarization on support structure adjustment process and deformation control concept during the construction of sections with varying degrees of large deformation in inclined shaft and main tunnel were conducted, with the results showing that: (1) for the general large deformation, appropriate improvement of strength and stiffness of support structure can effectively inhibit deformation and support damage; (2) for the medium large deformation, further improvement of strength and stiffness of support structure are to be taken, or radial grouting, lengthened and more dense anchor bolt and local addition of cover arch are to be adopted to basically con?
trol deformation; (3) for the severe to extremely severe deformations, comprehensive measures like advance stress release, long and short anchoring system to strengthen surrounding rock and application of multi-layer large-stiffness support, etc. must be adopted to effectively control deformation and ensure construction safety and long-term stability of the structure.
2019, Vol. 56 