Protection system for debris flow induced by side slope slag hanging in construction period and construction method

The invention discloses a construction method of a protection system for debris flow induced by side slope slag hanging in the construction period. The protection system comprises a rotary energy dissipation fender pile group arranged at the position of a gully bealock. A reinforced gabion array is arranged at the gully outlet and comprises a plurality of reinforced gabions arranged in the shape of a Chinese character'pin '. The triangular lateral notches of the reinforced gabion array are provided with water passing blocking nets for secondary blocking of rock ballast in debris flow. The periphery of the reinforced gabion array is provided with a permeable impoundment pool which is used for precipitating silt in debris flow and is arranged in an opening mode; a flow guide notch is formed in the open side edge of the water-permeable retaining pond, and a drainage guide groove used for drainage of water flow and a plant protection belt used for foundation fixing of the construction platform needing to be prote