Abstract During the construction of a long and shallow double-arch tunnel with a concealed mid-partition, some technical difficulties are encountered, such as the complicated construction procedure of pipe-roof advance support,stress concentrations at both the haunch and side wall while excavating the pilot tunnel and poor stability of sandwiched rock on top of the mid-partition, etc. Using a specific project as an example, pipe-roof technology without a chamber was adopted to decrease the influence on construction efficiency of the double-arch tunnel. The optimized design and calculation analysis of a double-arch tunnel with a concealed mid-partition was carried out with the three aspects of installing long, meshy non-isoparametric system bolts at the top of mid-partition; utilizing a smooth transition between the mid-partition and preliminary lining of the pilot tunnel; and installing suspended self-drilling rock bolts on both sides of the temporary mid-partition. Analysis results show that the construction safety of a double-arch tunnel with a concealed mid-partition is greatly improved by the above-mentioned optimizations; for a double-arch tunnel with a concealed mid-partition, using optimized structures and pipe-roof technology without a chamber enables rapid and safe construction, indicating a positive prospect for engineering application.
Abstract：
During the construction of a long and shallow double-arch tunnel with a concealed mid-partition, some technical difficulties are encountered, such as the complicated construction procedure of pipe-roof advance support,stress concentrations at both the haunch and side wall while excavating the pilot tunnel and poor stability of sandwiched rock on top of the mid-partition, etc. Using a specific project as an example, pipe-roof technology without a chamber was adopted to decrease the influence on construction efficiency of the double-arch tunnel. The optimized design and calculation analysis of a double-arch tunnel with a concealed mid-partition was carried out with the three aspects of installing long, meshy non-isoparametric system bolts at the top of mid-partition; utilizing a smooth transition between the mid-partition and preliminary lining of the pilot tunnel; and installing suspended self-drilling rock bolts on both sides of the temporary mid-partition. Analysis results show that the construction safety of a double-arch tunnel with a concealed mid-partition is greatly improved by the above-mentioned optimizations; for a double-arch tunnel with a concealed mid-partition, using optimized structures and pipe-roof technology without a chamber enables rapid and safe construction, indicating a positive prospect for engineering application.
LI Hai-Jun- 1 Zhang-Wan-Bin- 1 Wang-Ming-Nian- 2
.Optimized Design for the Construction of a Double-Arch Tunnel with a Concealed Mid-Partition[J] MODERN TUNNELLING TECHNOLOGY, 2016,V53(5): 183-187
2016, Vol. 53 