Execution Notes for Nail, Anchor, and Headplates

  • Use only standard, rust-free materials in excavation and soil stabilization projects.

  • Rebar connections must be done by mechanical couplings or high-heat forging welds only.

  • Injection hoses for nailing or anchoring must be at least 2 for holes up to 12m (1 supply, 1 return) and 3 for holes over 12m (1 supply, 2 return).

  • Free length of anchors must be coated with grease sleeves, sealed at both ends.

  • Check reinforcement element length before insertion into boreholes.

  • Hole plates must match reinforcing elements and comply with structural calculation documents.

  • For rebar reinforcements, threads must match rebar diameter, and nuts must have proper thickness unless otherwise noted in calculations.

  • Allowed tolerance for borehole length is ±25 cm; deviations beyond require designer and supervisor approval.

  • Use spacers to center reinforcement elements in boreholes; spacing should not exceed 3 meters.

  • Use centralizers to position reinforcement elements properly inside boreholes.

  • Tolerances for drilling position are ±25 cm and drilling angle ±1°.

  • Minimum thread length for nail head connections is 10 cm.

  • Prepare reinforcement elements (especially strands) on the hoist, not on the ground.

  • If cavities are encountered during drilling, use packers or redirect boreholes at different angles.

  • Use expanding grout or wedges behind nails and anchors.

  • Follow safety protocols during installation and tensioning of anchor heads.

  • Ensure full connection of nail and anchor heads to shotcrete, steel piles, or concrete piles.

  • Avoid cutting or bending nail or strand ends until the project ends to allow testing if needed.

Additional Notes on Self-Drilling Rods (Rebar Alternative)

  • High risk of borehole deviation with self-drilling rods; thorough site supervision of the first two rows is mandatory.

  • Cross-sectional area of self-drilling rods must match rebar area in stabilization drawings.

  • Self-drilling rods are not recommended as anchors.

Source: General Guidelines for Supervising Engineers