Tunnel construction method for spanning gully section

The invention provides a tunnel construction method for spanning a gully section. The tunnel construction method comprises the following steps of, 1, sequentially driving a plurality of anchor rods along a direction from a gully into a mountain and parallel to the axis of a tunnel, and making parts of the anchor rods be exposed outside the mountain; 2, treating the gully by using backfill soil toenable the anchor rods exposed the outside the mountain to be positioned inside the backfill soil; 3, after the backfilling is completed, constructing a drainage ditch at the top of the backfill soil;4, under the support of a double-layer advanced small pipe, constructing a hidden hole in the gully section; and 5, after the construction of the hidden hole is completed, carrying out backfilling onsurface soil to restore the agricultural cultivation. According to the tunnel construction method, the backfilling treatment is carried out on the gully section in advance, and anchor rod connectionis additionally arranged bet