Arch-covering-method tunnel-entering construction method and arch-covering-method tunnel-entering supporting structure

The invention provides an arch-covering-method tunnel-entering construction method and an arch-covering-method tunnel-entering supporting structure. In the process of excavating a main tunnel conversion channel B, a door-shaped support is erected as a support while excavating is conducted, after excavating of the main tunnel conversion channel B is completed, a second supporting structure is erected to strengthen the support, and finally a primary supporting ring beam, a first longitudinal beam, a supporting column beam and an arch foot longitudinal beam which are made of reinforced concrete materials are poured; the primary supporting ring beam, the first longitudinal beam and the arch foot longitudinal beam can stably support the second supporting structure, the supporting strength of the junction of the main tunnel conversion channel B and a construction channel A is greatly improved through the primary supporting ring beam, the first longitudinal beam and the supporting column beam, conversion of a stress