Break-out and break-in supporting structure for soft stratum shallow-buried large-section tunnel and construction method of break-out and break-in supporting structure

The invention relates to a break-out and break-in supporting structure for a soft stratum shallow-buried large-section tunnel and a construction method of the break-out and break-in supporting structure. The supporting structure comprises an upper step sleeve arch, wherein a sleeve is pre-buried in the sleeve arch; a tunnel vault arc-shaped pipe shed combination is built from the sleeve arch to the inside of a mountain body through the sleeve; a horizontal pipe shed arranged between an upper step and a lower step is also fixed between the two ends of the lower part of the arc-shaped pipe shed in the tunnel break-out and break-in mountain body; an arc-shaped middle upper pipe shed which is vertically arranged is also arranged between the upper side of the middle part of the horizontal pipe shed and the arc-shaped pipe shed of the tunnel vault; and a middle lower pipe shed connected with the middle upper pipe shed is also arranged between the lower side of the middle part of the horizontal pipe shed and the arc