The Section for Ground Anchors and Soil Nails

Activities:

The activities of the Section for Ground Anchors and Soil Nails are mainly concerned with the construction of new anchored structures and with continuous surveillance of the production, installation and testing of ground anchors and soil nails, mainly in the case of:

• retaining walls forming part of structures for Slovenia's national motorway construction program, as well as for the structures of regional road and railway networks,
• anchored supporting structures for excavations, such as sheet pile walls, drilled piles, slurry walls, soldier piles and lagging,
• works which are needed to provide stability to the structures of hydro-electric power plants, in order to establish a favourable stress distribution and to prevent the excessive deformation of high dams,
• works whose aim is to counteract uplift forces in underground structures, foundations and basements, due to buoyancy effects,
• protection and stabilization of tunnels and other underground / cut-and-cover structures,
• preventive stabilization of existing slopes and embankments,
• anchoring of bridge abutments,
• stabilization of eccentrically loaded foundation structures,
• weak slope stabilization works,
• protection of deep excavation works.

Ground anchors

• performance of continuous surveillance:
  • verification of the load-carrying capacity of installed prestressed anchors, including investigation tests on individual test anchors, in order to determine their ultimate load resistance at the grout/ground interface, as well as suitability and acceptance tests, on all anchors, of anchored structures,
  • electrical testing of the corrosion protection of installed permanent prestressed anchors (ERM I and ERM II),
• conducting of investigation tests to failure of prestressed anchors,
• evaluation and analysis of the results of investigation tests of prestressed anchors, and definition of parameters for the structural works, using our own software.
  

Soil nails

• loading tests of different types of soil nails in order to verify their pull-out resistance:
  • design investigation tests,
  • suitability tests,
  • acceptance tests.

Common activities for all types of ground anchors and soil nails:

• certification of anchors and soil nails, as construction products, and the performance of continuous surveillance of factory production control,
• certification of the installation of anchors and soil nails, and performance of continuous surveillance of such works,
• verification of procedures used to install ground anchors and soil nails,
• preparation of expert opinions about anchoring works and anchored structures,
• preparation of technical specification conditions for ground anchors and soil nails,
• preparation of record forms about installed ground anchors and soil nails,
• together with ZAG's other organizational units:
  • mechanical testing of anchorage components,
  • geotechnical monitoring of drilling works for the installation of anchors,
  • laboratory tests of materials for anchorage components and assemblies,
  • inspections of existing anchored structures and installed anchors, and preparation of expert opinions about such structures and anchors.

Testing equipment:

• Powerteam stressing equipment, with a P55 hydraulic pump and a RH 503 hydraulic jack,
• a 1000 kN force measuring device, with a WIGAmeter N100 force indicator,
• a Novotechnik TRS100 T.12 digital displacement transducer, on a stand,
• a Smartec insulation resistance measuring device, manufactured by Metrel,
• a Smartec earthing resistance measuring device, manufactured by Metrel.

Significant research and development projects

• "Installation and testing of test anchors for the north portal of the "V zideh" tunnel" - a research and developmental project for DARS, d.d., the Company for Motorways in Slovenia (1997),
• "Development of additional criteria for the installation of permanent ground anchors" - a research and developmental project for DARS, d.d., the Company for Motorways in Slovenia (2003).