Soft surrounding rock tunnel face primary support subsection parallel operation construction method

The invention discloses a soft surrounding rock tunnel face initial support subsection parallel operation construction method, which relates to the technical field of tunnel and underground engineering, and comprises the following steps: after an upper step of a tunnel is excavated, firstly, a layer of early strength concrete is initially sprayed towards an excavation face, then, a positioning stress top longitudinal beam and an upper arch frame are installed, and the upper step of the tunnel is excavated; then a flexible force application device is arranged behind the upper arch frame and applies stress, so that the upper arch frame can provide supporting force for the surrounding rock in time, then the arch frames are continuously excavated and arranged, stress is applied to the arch frames and the surrounding rock, and concrete is sprayed between the arch frames and is left behind for parallel operation during excavation and arch frame erection. Different technical guarantees are provided for different typ