Super-large-span tunnel supporting structure and excavation construction method

The invention discloses a super-large-span tunnel supporting structure and an excavation construction method. The super-large-span tunnel supporting structure comprises a stress part, and the stress part is located above a tunnel structure; the pilot tunnels are arranged on the two sides of the tunnel structure and communicate with the tunnel structure; the supporting part is connected with the stress part; and the inclined strut is connected between the stress part and the supporting part, so that the problem that the overlying load of the shallow-buried super-large-span tunnel is large is solved. The method has the advantages that the safety of the shallow-buried super-large-span tunnel is ensured through transmission of prestress and the formed rectangular cross-section beam through the support; the formed combined structure is equivalent to advanced reinforcement of the stratum, the excavation section can be enlarged on the basis, and the construction efficiency of the tunnel is greatly improved on the ba