The micropile, also known as root pile, is a small diameter cast-in-situ bored pile formed by cement grout injection and subsequently equipped with lost, steel reinforcement element (bar, steel tube, H-type profile…). The boring is performed with compressed air or by means of a supporting drilling fluid (water, cement grout, bentonite).
Installation process in accordance with the requirements of the “NBN EN 14199 : Micro piles” standard
1. Placement of the first section of the steel drill casing equipped with the drill bit fixed on a rod. Start of the boring process under fluid flushed inside the drill casing.
2. Coupling of the additional casing segments and continued boring under supporting drilling fluid until the required depth has been reached
3. After reaching the design depth, replacement of the drilling fluid by the primary grout
Injection of cement grout under pressure. The micropile is formed by single stage grouting under the so-called “unitary and global” grouting under low pressure or I.G.U. mode (« Injection Globale et Unitaire ») or the micropile is formed by multi-step grouting under the so-called “repetitive and selective” grouting under high pressure or I.R.S. mode (“Injection Répétitive et Sélective”).
4. Completed micropile