The invention relates to the field of
tunnel construction, in particular to a construction method for newly increasing an arched open
cut tunnel at a railway operating line tunnel portal. The construction method solves the problems that the conventional construction method for newly increasing the arched open
cut tunnel at the railway operating line tunnel portal has complex process, difficult operation, low construction efficiency, large
safety risk, poor construction quality and the like. The construction method comprises the following steps of: surveying setting-out, construction of manually digging hole piles,
fiber concrete slab
prefabrication,
joist construction,
processing and
assembly of an H profile
steel frame, short side wall construction, arch construction of the arched open
cut tunnel, end-sealing concrete construction and the like. The
fiber concrete slab and the profile
steel frame form an integral structure, so the stability is good, and the safety is ensured; the method avoids formwork removal operation after arch concrete pouring is finished, simplifies the construction process, accelerates the construction progress, and has considerable economic benefit; the profile
steel frame is uniformly processed in a
processing factory and pre-assembled and hoisted on site so as to shorten the
operation time and improve the construction efficiency; and the
fiber concrete slab is prefabricated in the factory and then arranged on site, so the arched open cut tunnel has
surface finish and attractive appearance.