Five-level surrounding rock pilot tunnel supporting mechanism for tunnel

The utility model discloses a tunnel five-level surrounding rock pilot tunnel supporting mechanism which comprises a lead screw set which comprises a first row of lead screws and a second row of lead screws. The first row of screw rods are arranged above the second row of screw rods, and the distance between the first row of screw rods is two times that between the arch frames; the first row of screw rods and the second row of screw rods are respectively three screw rods which are transversely arranged and have the same interval with the interval of arch frames during construction; the first row of lead screws are placed at the position 40% of the height below the top of the pilot tunnel, the length of the first row of lead screws and the length of the second row of lead screws are equal to the width of the pilot tunnel where the lead screws are located, I-shaped steel is welded to the left sides and the right sides of the three lead screws on the first row of lead screws and the second row of lead screws, an