Construction method of railway single-track tunnel with central deeply-buried ditch in high and cold area

The invention discloses a construction method of a railway single-track tunnel with a central deeply-buried ditch in a high and cold area. The construction method includes: performing staking out in survey to determine the specific position of the central deeply-buried ditch; performing drilling and blasting on a tunnel face, synchronously drilling vertical presplit holes, transverse auxiliary holes and peripheral holes in the to-be-excavated area of the excavation face of the central deeply-buried ditch, and then performing excavation; performing tunnel face residue discharge and tunnel primary support, and performing central deeply-buried ditch residue discharge and construction; repeating the steps above for 3-5 times, and performing inverted arch construction once when the excavation face of the central deeply-buried ditch advances 9-12m; performing circulating construction according to the steps above until the construction of the whole tunnel is completed. The construction methodhas the advantages that