Micro Pile Installation: Complete Step-by-Step Guide

Micro piles (also called mini piles) are deep foundation elements installed in restricted access or challenging ground conditions. The installation process includes four main stages: drilling, driving, grouting, and reinforcement.

1. Drilling

If direct driving of micro pile pipes is not feasible due to surface conditions such as floor coverings, lean concrete, or dense soil layers, drilling is required.

The drilling can be done using different methods such as:

  • Rotary drilling

  • DTH (Down-the-Hole) drilling, which combines rotation and percussion

Drilling continues until a depth is reached where pile driving is possible. In some cases, the full depth of the micro pile is achieved via drilling.

2. Pipe Driving

Once the borehole is prepared, steel casing pipes are driven into the drilled hole.

  • The process starts with a pointed-tip pipe section.

  • After driving the first section, the second pipe is welded or connected and driven down.

  • This continues until the required depth is reached.

  • Typical pipe length per segment is 2 meters.

3. Grouting

After pipe driving is completed, cement grouting is performed to bond the pile to the surrounding soil.

Grouting involves three main components:

  • Primary mixer

  • Secondary mixer

  • Injection pump

A cement-water mix is prepared and injected using packer systems through perforated casings, ensuring full contact between the pile and the surrounding soil, thereby enhancing the mechanical properties of the soil.

4. Reinforcement & Flange Installation

The final stage involves:

  • Inserting the reinforcement bars inside the micro pile pipe before the cement grout sets

  • Welding a flange to the reinforcement bar, ensuring:

    • Proper connection to the foundation

    • Punching shear resistance in the final structure