Construction method conversion construction method for ultra-long-span tunnels in ⅳ-level to ⅳ-level surrounding rock sections

Abstract

The invention discloses a construction method conversion construction method for super-long-span tunnels in the surrounding rock section of level V to level IV. Controlled excavation is adopted to keep the same elevation of the arching line, and the double side wall pilot pit method of the surrounding rock is used as the leading and leading method in the construction of the transition section. The temporary middle wall of the left pilot pit and the temporary middle wall of the right pilot pit on both sides of the rear guide move to the middle of the tunnel at the same time, until the temporary middle wall of the left pilot pit and the temporary middle wall of the right pilot pit touch, and the temporary inverted arch Lock-foot anchors are applied on both sides; then the temporary middle wall of the right pilot pit is removed, and the temporary middle wall of the left pilot pit is retained as the middle temporary middle wall of the CRD method. This method transitions from the double-side-wall pilot-pit method to the CRD method in the horizontal direction, avoiding the time interval between construction method conversions, and reducing the disturbance of the surrounding rock caused by the removal of the temporary support of the double-side-wall pilot-pit method in the later stage, thus speeding up the construction. , save the construction period, avoid idle work, and improve the economic benefits of tunnel construction.

Description

technical field [0001] The invention relates to traffic fields such as highway tunnels and underground engineering technology, and in particular relates to a construction method for super-large-span highway tunnels in the construction method conversion of level V to level IV surrounding rock sections. Background technique [0002] In the process of highway tunnel and underground engineering traffic construction, it is often necessary to select different excavation methods according to different geological conditions of the surrounding rock of the tunnel, but the conversion between different excavation methods has been ignored, and there is no domestic design of ultra-long-span highway tunnels. , Construction codes and standards. In actual construction, the conversion of construction methods has no basis and is chaotic, and problems such as conservative, slow speed, and high risk often occur in the replacement process of construction methods. [0003] In the conversion proce...

AI Technical Summary

Problems solved by technology

Moreover, when the temporary mid-wall moves sideways, due to the constant changes in the length and curvature of the mid-wall, the steel frame processing plant needs to continue to design and process, thus increasing the construction cost and prolonging the construction period

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