Annex E

(informative)

Borehole testing and pregrouting

For micropiles installed in weathered and strongly fissured rock borehole testing and pregrouting may be necessary to avoid uncontrolled loss of grout and to guarantee the required grout cover of the bearing element.

The likelihood of cement grout loss can be assessed from an analysis of a water injection test. Routinely a falling head test is applied to the borehole or part of the borehole length via a packer. Pregrouting is not usually required if leakage or water loss in the bore hole or part of the borehole is less than 5 l/min at an excess head of 0,1 MPa measured over a period of 10 min.

Pregrouting is carried out by filling the borehole with a cement based grout. Sand/cement grout is commonly employed in rock with partially filled or open fissures to reduce grout consumption.

On completion of pregrouting the borehole should be retested and if necessary, the grouting process should be repeated after redrilling.

 

Annex F

(informative)

Guideline for the preparation of a record for several drilled micropiles

 

Micropile contractor Responsible at site			Sheet No. Date:
			Micropile: type, borehole diameter Reinforcement: type, grade, dia., spacers Grout: cement quality, w/c–ratio Concrete: class, max. grain, consistency Placing method: casing, grout tube, tremie Drilling method: equipment, drilling fluid Specials:
Site, location Client Contract
Drawing No. Total quantity of micropiles Pile length above/below platform Level of: site platform ground water
Micropile number:
	Date of construction
	Start of drilling, time (hr)
	Interruptions (hrs)
	Obstructions at depth (m)
	Depth of micropile (m)
	Depth of casing (m)
	Length of reinforcement (m)
	Length above/below ground (m)
	No. and location of joints/welds
	Spacers at distance (m), quantity
	Borehole testing (at depth/ bar)
	Pregrouting (ltr or kg / bar)
	Grout/concrete volume (ltr or kg)
	Max. pressure (bar)
	Site tests of grout/concrete (type)
	Base/shaft enlargement (ltr/dia.)
	Post grouting (ltr or kg / bar)
	Deviation of position (mm): x,y
	Deviation of inclination (°)

 

Annex G

(informative)

Guideline for the preparation of a record for several driven micropiles

 

Micropile contractor Responsible at site			Sheet No. Date:
			Micropile: steel concrete composite Diameter/max. extension (mm): Shaft: toe: Shape, material of toe: Bearing element: type, grade: dia./max. extension (mm): spacer type: prefabricated concrete: class In–situ concrete: class, max. grain size, consistency: Grout: cement quality, w/c–ratio Placing method: casing, grout tube, tremie Driving method: equipment, driving aid
Site, location Client Contract
Drawing No. Total quantity of micropiles Pile length above platform Level of: Site platform ground water Specials
Micropile number:
	Date of construction
	Driving time: from – to (hrs)
	Interruptions (min)
	Obstructions at depth (m)
	Depth in ground of micropile (m)
	Length of bearing element (m)
	Length above ground (m)
	No. and location of joints/welds
	Spacers: at centers (m), quantity
	Grout/concrete volume (ltr or kg)
	Max. pressure (bar)
	Site tests of grout/concrete (type)
	Base enlargement volume (ltr)
	Post grouting (ltr or kg / bar)
	Deviation of position (mm): x,y
	Deviation of inclination (°)

 

Bibliography

EN 196, Methods of testing cement.

EN 10149, Hot rolled flat products made of high yield strength steels for cold forming.

EN 287–1:2004, Qualification test of welders – Fusion welding – Part 1: Steels

EN ISO 15607:2003, Specification and qualification of welding procedures for metallic materials. , General rules (ISO 15607–2003).

EN 288–2:1992, Specification and approval of welding procedures for metallic materials. Part 2: Welding procedure specification for arc welding.

EN ISO 15614–1, Specification and qualification of welding procedures for metallic materials. Welding procedure test – Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys (ISO 15614–1:2004).

EN 445:1996, Grout for prestressing tendons – Test methods.

EN 447, Grout for prestressing tendons – Specification for common grout.

EN 499:1994, Welding consumables – Covered electrodes for manual metal arc welding of non alloy and fine grain steels – Classification.

EN 1997-2, Eurocode 7: Geotechnical design – Part 2: Ground investigation and testing.

EN 10219–1:1997, Cold formed welded structural hollow sections of non–alloy and fine grain steels – Part 1: Technical delivery requirements

EN 1997–3, Eurocode 7: Geotechnical design – Part 3: Design assisted by field testing.

EN 12716:2001, Execution of special geotechnical works – Jet–grouting.

EN ISO 4063:2000, Welding and allied processes – Nomenclature of processes and reference numbers (ISO 4063:1998)

EN ISO 5817:2003, Welding – Fusion–welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections (ISO 5817:2003)

EN ISO 9692–2:1998, Welding and allied processes – Joint preparation – Part 2: Submerged arc welding of steels (ISO 9692–2:1998)