Recent Construction Sites of Micropiles in Germany

Thomas F. Herbst

Wessling / Munich Germany

5th IWM 2003 Seattle – Session 2

1. Replacement of the 100 years old lock Lauenburg of the Elbe-Lübeck Channel

Cross section of the lock

Lock Lauenburg: Aerial view during construction 2003

View of the site with 3 floating drill rigs

Execution: Bauer

Micropile GEWI dia. 63,5 mm anchored in underwater concrete slab

Underwater installation from pontoon

Length: 23 to 27 m

2. Retrofitting of a bridge abutment in Bad Waldsee

Execution: Bilfinger&Berger

Micropile GEWI dia. 50mm in sections, borehole dia. 150 mm

Free head room: max. 2 m

Soil: Gravel and silt

Rotary drilling with external cementitious flushing

Group testing with 3 GEWI piles at Bad Waldstadt site

Single and group testing of each micropile up to 1,25 service load

Service Load:

300 kN per micropile

3. Retrofitting of settled drainage tunnel of the waste disposal Kahlenberg

Cross section

Pump shaft

Settlements up to 24cm

Ore rib

Drainage tunnel

Auffüllung

Erzliegendes

Auffüllung

Erzliegendes

Grouted micropile and micropile with inflatable bulb

Auffüllung

Erzliegendes

fill

substratum

Micropile with inflatable bulb (system Bauer)

groundmicropile shaft with bearing element

A) Design for preloadable micropile head:

Solutions by Bauer

structural element

B) Preloading of the micropile and lifting of the structure

micropile shaft with bearing

element

structural element

ground

s

micropile shaft with bearing

element ground

structural element

grouted gap

C) Lifted structural element after preloading of the micropile, tightening the lock nut and grouting

D) Micropile head for preloading in case of an existing structure

sexisting structural

element

groundmicropile shaft with bearing element

Bauer - Klemm drill rig for low head room

116 micropiles in total

• 96 grouted micropiles

• 20 micropiles with inflatable bulb

Total amount of micropiles for the drainage tunnel of the waste disposal Kahlenbach installed by Bauer :

Ore rib