Quality Control of Reinforcement Elements in Soil Nailing and Anchoring

  • It is recommended to purchase strands and their accessories from a single manufacturer to ensure reliable mechanical engagement between wedges and strands.

  • Visual inspection: No corrosion, deformation, or surface defects.

  • Mechanical properties: Yield strength, ultimate strength, modulus of elasticity, etc.

Note: In some small-scale projects under supervision, using AII rebar instead of AIII has become unfortunately common. This substitution is critical and must be avoided.

Frequency of Quality Control Testing

Quality Control of Mesh and Shotcrete

  • Sand quality: Preferably angular, washed, and with a sand equivalent value over 65. Sand must be free of clay to achieve adequate strength.

  • Mesh appearance: Free from corrosion and deformation.

  • Mechanical testing of mesh: Yield strength, ultimate strength, modulus of elasticity.

  • Testing frequency: Regular and documented.

Quality Control of Steel Plates, Nuts, and Other Metal Components

  • Steel plates: Must meet both visual and mechanical standards.

  • Nuts: Should conform to standard strength and thread quality.

  • Couplings and anchor heads (wedges, etc.): Require strength verification.

  • Testing frequency: Based on project size and standards.

Quality Control of Cement, Water, and Grout Used in Soil Nailing

  • Cement properties such as setting time significantly impact grout performance and anchor pullout capacity.

  • Water quality must meet standards similar to potable water used in concrete. Chemical testing of water is advised in large-scale projects.

  • Marsh cone testing is recommended to control grout flow and consistency.

  • Additives may be used only after trial tests and confirmed strength results from approved laboratories.

  • Regular testing should be implemented and logged.

Quality Control of Grouting Hoses, Air Hoses, and Drilling Rods

  • Injection hoses must withstand the required injection pressures.

  • Air hoses should be made of durable, erosion-resistant materials and connected with secure, appropriate fittings.

  • Grout sleeves must be sealed properly to prevent grout from entering the unbonded length.

Note: Air hose detachment during soil nailing is a common hazard and has caused serious accidents in various projects. Proper hose fittings and strict adherence to safety standards are essential.

  • Drilling rods must be made of high-strength alloys, capable of deep drilling. Threads must be intact for proper rod connections.

Quality Control of Concrete and Steel Piles Used in Excavation Stabilization

  • Welding must conform to the Iran National Building Code and the Iranian Welding Standards.

  • Steel cage fabrication and placement must follow standard building regulations.

  • Concrete quality and pouring operations must align with national concrete code (ABA).

  • Slump testing and temperature control should be conducted along with collecting 4 to 5 cube samples in large-scale projects.

  • If admixtures are used, slump and temperature must be checked before and after admixture addition on-site.