Drilling micro-piles sub-horizontally steel tubes to the contour of the tunnel section to be excavated is called "forepoling". Metal arches will support these micro-piles as the excavation progresses. 

It may consist of one or more stages, each of which has a free length of about ten meters. The length of the micro-piles may reach at about 18 m. A part of it will be overlapped by the next stage.

The objectives of this operation are to maintain the stability of the formation we are going through; maintain the stability of the forehead and limit settlements. 

This method can be performed bybmicro-piles machines, forepoling drilling machines and/or jumbo. 

In the first two cases the drilling is achieved with hammers DTH downhole, while with the Jumbo percussion is given by the hydraulic Roc-drill.

LTM is your supplyer for threaded tubes. You might need right hand or left hand threads with 1, 2 or 3 entries/starts, squared, rounded, tapered or your design threads, with drilled holes or one valves installed you can find a steady and reliable manufacture in our factory. we are open to show our facility to you.

Send us your inquiries, you will receive our speedy offer.


Ltm S.r.l. is a company that operates in the field of micropiles, since 1982. The main objective of Ltm is the one of supplying, high quality finished goods, constantly improving the workmanship, so to offer to the clients a superior product.

More aboutLTM
Forepoling English
Voute parapluie Français