Passive Anchor (Soil Nailing) Construction Method

Construction Methods

This construction method has been prepared to define the selection of machinery, equipment, materials, preparation, application, and control procedures required for passive anchor (soil nail) production.
The implementation shall be carried out in accordance with TS EN 14490 – Execution of Special Geotechnical Works – Soil Nailing.

1. Preparation of the Work Area

  • The construction area and access roads shall be kept level and dry to ensure efficient machine and personnel operation.

  • Surface drainage shall be installed to keep the platform dry.

  • Heavy machinery platforms shall be compacted to prevent sinking deeper than 10 cm.

  • Excavation shall be carried out in stages to ensure slope stability.

2. Soil Information
The length, inclination, spacing and type of soil nails shall be determined based on soil investigation reports and project requirements.

3. Environmental Information
Underground and above-ground obstacles such as concrete blocks, steel elements, utilities and channels shall be identified and removed or protected.

4. Positioning and Tolerances

  • Soil nail locations shall be marked individually by a professional surveying team.

  • Deviation tolerance from vertical/horizontal alignment shall not exceed 1/50.

  • Installation sequence must not disturb previously installed nails.

  • No drilling shall be done within a 1 m radius before a nail is fully completed.

5. Drilling Works

  • Soil nails are typically installed in drill holes with diameters between Ø90–150 mm.

  • The drilling method shall be selected according to soil type (auger, rotary drilling, DTH hammer, etc.).

  • Drill holes shall be cleaned, and groundwater presence shall be controlled to prevent collapse.

6. Installation of Steel Bars (Nails)

  • Reinforcing bars shall comply with relevant material standards.

  • Nails shall be placed without contamination (dust, mud, soil).

  • Centralizers shall be installed to ensure proper alignment inside the hole.

7. Grouting

  • Cement grout shall have a water/cement ratio suitable for soil conditions (commonly w/c = 0.45–0.55).

  • Grouting shall be performed from the bottom of the hole upward (tremie method) to ensure full bond.

  • Additional grouting may be applied in porous soils.

8. Shotcrete Application (if required)

  • After nailing, slope face may be stabilized using shotcrete and mesh reinforcements.

9. Quality Control and Records

  • Daily site work reports shall include the location, diameter, inclination, length, drilling depth, grout volume, and material details.

  • All works shall comply with quality standards YY.09 and material acceptance criteria T06.