The invention discloses a double-layer primary support structure of a weak surrounding
rock tunnel and a construction method thereof and belongs to the technical field of
tunnel construction. The double-layer primary support structure of the weak surrounding
rock tunnel comprises a single-layer
mesh reinforcement. The outside arc face of the single-layer
mesh reinforcement is provided with anchorholes. Anchor rods are inserted into the anchor holes. According to the double-layer primary support structure of the weak surrounding
rock tunnel, by means of mutual cooperation of the designed anchor rods, connection holes, bearings, rotating shafts, threaded rods, threaded cylinders, fins, pin shafts, limiting holes, an outer layer interrupted type arch frame, buffering devices, an advanced flexible net-structure protective cover, a buffering
air cushion layer and other structures, by changing the position relationship between the fins and the anchor rods, the stress area of the anchor rodscan be effectively increased, and then the anchorage effect of the anchor rods on the overall structure can be effectively improved; and meanwhile, the adopted flexible connection relationship can effectively weaken the degree of the problems that deformation time is long, the deformation amount is large, the deformation speed is rapid, the time of duration is long, a large area of surrounding rock extrudes and invades into a limitation bound, and the support cracks or damages severely.