The invention relates to the technical field of
tunnel construction, in particular to a construction method of a large-section tunnel. The construction method comprises the following steps:
zoning a section of a tunnel, wherein the section of the tunnel is zoned into a left upper zone, a left
middle zone, a left
lower zone, a middle upper zone, a middle
middle zone, a middle
lower zone, a right upper zone, a right
middle zone and a right
lower zone according to the upper-middle-lower direction and the left-middle-right direction; during excavation construction on the nine zones, firstly carrying out the excavation construction on zones at the left side and the right side of the tunnel, wherein the excavation construction is carried out on the zones at the left side and the right side of the tunnel from top to bottom, and primary support is carried out in time; then carrying out the excavation construction on the zones at the middle part of the tunnel, wherein the excavation construction is carried out on the zones at the middle part of the tunnel from top to bottom, and primary support is carried out in time. A
closed loop is formed as section steel supporting frames are arranged around the outlines of all the zones, so that the structure of the tunnel is stable, safety construction can be ensured, the cost of temporary
engineering is reduced, all zones can be subjected to synchronous construction, the operation of various machines is facilitated, the working efficiency is increased, the construction progress is quickened, and the construction of accessory structures such as an entrance / exit and an air duct is convenient.