Pressure grouted micropile designs are as diverse as the geological conditions in which they are installed. Bond zone diameter and depth are key elements in optimizing this micropile design and are greatly influenced by the in-situ geological characteristics. Casing material and wall thickness, the threaded bar, grout pressure and grouting strengths, will always be considered by the design engineer to best customize the design and ensure the micropile meets or exceeds the design requirements.
Pressure grouted micropile designs are tailored to meet specific performance requirements for each individual project. This capability can be used to support heavy foundation loads over unsuitable subgrades, provide tension capacity to stabilize tall structures and provide lateral strength for use in various shoring applications.
Pressure grouted micropiles are generally used when there are difficult ground conditions such as natural or man made obstructions, sensitive ground or adjacent structures, limited access/low headroom and or karstic geology.
This micropile type is typically drilled into unconsolidated materials such as soil, sand or broken rock to develop a bond zone which is incorporated into the micropile design. Grout is then placed under pressure to maximize the pile capacity. The bond zone provides multiple structural contributions including compression, tension and lateral loads. This micropile type is commonly used to replace deteriorating foundation systems, for the renovation of structures, to support structures affected by adjacent construction, for seismic retrofitting or in-situ reinforcement including embankment, slope and landslide stabilization. They are often drilled into more challenging subsurface conditions where unconsolidated or broken and fractured strata exist.
Pressure grouted micropiles increase the stability and load bearing capacity of the surrounding ground. The following demonstrate just a small sampling of the successful projects having pressure grouted micropiles as part of the foundation: