Outline

High Capacity Micropile

Execution Process

Seismic Retrofitting of Existing Pile Foundation

under the Bridge

Seismic Retrofit Construction of The Water Service Station

High capacity micro piles (HMP) combine the drilling technology used by the ground anchor method and the pressurizing injection technology of grouting. HMP uses high strength steel pipes in addition to deformed bars as reinforcement, which ensures a high bearing capacity. They can be used in narrow spaces and where overhead clearance is limited

HMP are installed using a small drilling machine. The HMP uses deformed bar and the steel pipe reinforcement, and is completed by the grout injection.

　

Outline of High Capacity Micro Pile

Grout

Deformed Bar Joint

Top of Footing Bearing Plate

Cased Upper Part (section A-A')

Steel Casing Pipe Joint

Drill bit

Steel Casing Pipe

Pile Uncased Bond Part (section C-C')

C-C' 　

A-A' 　

Total HMP Length Steel Casing

Casin

g Plu

nge

Length

　 Pressure Grouted HMP Bond Length

Cased Upper HMP Length

Top of Pile Part

Non-steel Casing

Deformed Bar

B-B' 　 Casing Plunge Bond Part

(section B-B')

Grout

Deformed Bar

Deformed Bar

Centralizer

HMP ; High Capacity Micropile

Grout

Pile Uncased Length

Soft Ground

Bearing Stratum

Deformed Bar

Grout

Execution Process of HMP

、 Water or air Inner rod

Deformed bar Inject grout under pressure

Adding HMP steel casing Bearing plate

Adding HMP steel casing

Grout

Remove inner drill bit & rod

① ② Place

deformed bar ③

Initial injection ④ ⑤

Reinserting HMP steel

casing ⑥

Treatment of pile head ⑦

Remove temporary casing, inject further grout under pressure as applicable Excavation

(casing boring)

HMP steel casing

Remove temporary casing

Bearing Stratum

Soft Ground