Composite buffering and energy-absorbing tunnel yielding supporting system

The invention discloses a composite buffering and energy-absorbing tunnel yielding supporting system which comprises a plurality of I-shaped primary supports arranged in the longitudinal direction of a tunnel, and a compression energy-absorbing layer and a reinforced concrete lining structure are sequentially arranged outside the primary supports. The primary support comprises I-shaped steel arch frames composed of a plurality of I-shaped steel sections, and the I-shaped steel sections on each I-shaped steel arch frame are fixedly connected through longitudinal reinforcing connecting plates and groove steel plates. The adjacent I-shaped steel sections of the primary support are installed at the two ends of the longitudinal reinforcing connecting plates respectively. The two I-shaped steel arch frames form a primary support of a closed structure, flange plates are fixed to the ends of the two I-shaped steel arch frames, and the flange plates are fixedly installed on the yielding component; and the yielding com