Micropiles, also called mini piles, are a deep foundation system used to create foundations for a variety of project types, including highways, bridges and transmission tower projects. They are especially useful at sites with difficult or restricted access, or with environmental sensitivity. Micropiles are usually in the diameter ranges of 60 to 300 mm. Installation of micropiles through top soil, sand and cobblestones, overburden and into soil rock can be achieved using Air Rotary or Mud Rotary drilling, impact driving, jacking, vibrating or screwing machinery. Micropiles can also be used to construct a grout column around the shaft of a standard Helical Pile system, allowing for use in higher load applications.
Direct Pipe Pile
Direct Pipe Pile (DPP) is a micro pile technique used for deep foundations in ground formations of many types. They are typically achieved using Air Rotary drilling rigs which advance the hollow pipe through ground formations with the help of a specialized drill bit. The steel pipe is then filled with a grout-cement which acts as extra corrosion protection, it can also increase the strength of the pile.
Also called caissons, drilled shafts, drilled piers or Cast-in-Situ piles. A borehole is drilled into the ground, then concrete (and often some sort of reinforcing) is placed into the borehole to form the pile. Rotary boring techniques allow larger diameter piles than any other piling method and permit pile construction through particularly dense or hard strata. Construction methods depend on the geology of the site; in particular, whether boring is to be undertaken in 'dry' ground conditions or through water-saturated strata. Casing is often used when the sides of the borehole are likely to slough off before concrete is poured. Both the diameter of the pile and the depth of the pile are highly specific to the ground conditions, loading conditions, and nature of the project. Pile depths may vary substantially across a project if the bearing layer is not level.
Push Piles/ Jacked Piers
Push Piles also known as Jacked Piers or Push Piers, are another type of deep foundation. They are used for structural support, essentially used to stop settlement and/or raise structure. This type of method uses a smaller diameter steel pipe. Piles advance in the ground formation by the pressure of hydraulic jacks. Prior to the installation of the piles, a steel bracket is mounted to the foundation of the structure acting as the connection. Then, a hydraulic jack ties into that bracket. Pressure gauges are joined into the circuit to monitor the pressures of each zone the pile advances through. When the pile reaches the desired depth, it gets locked off at a designated load. The finished operation is either lifted by the bottle jacks simultaneously to lift the structure or locked off at a certain pressure to resist the structure from moving.
Screwpiles/ Helical Piles
Screwpiles also known as Helical Piles are another deep foundation technique used for structural support and/or earth retention projects. Screw piles are galvanized or bare metal pipe with helical fins that are turned into the ground by various equipment to a required depth. Screwpiles are the most rapid installation pilling; they also cause the least disturbance to the soil during the installation. Screwpiles are known for potentially being the most cost-efficient alternative out of all the piling techniques.