Mini/Micro Segmental Piling method is used for limited site and headroom. To use this method, we use rigs of range 2,5-Ton and door entrance drivable rig, which can pile up to 450mm in diameter with maximum 15mm depth. These augers come in various diameters (1-1.5m section) and can be installed manually. This method is the best for chalk or london clay. During this method, borehole needs to stay formed and open.
This micro segmental piling process is suitable for limited site access and height headroom. For this process, we use rig range from a 3-Ton rig which can quickly drill piles from 250mm to 450mm in diameter, with extreme depth 15m, and up to almost 15-Ton piling rig which drills from 300mm up to 600mm diameter down to 17m. Augers come in the market come on 1m to 2m sections, and these are installed metre by metre down manually.
Drop Hammer method lets us to install metal tubes in the earth. We do by releasing weight on them, driving them deep down until a particular depth is attained. After that, these tubes are cut off to the accurate height, reinforced and concreted. These driven piles are the best solution for those grounds where slack material wouldn’t let a borehole to be formed. Once those tubes get penetrated in the surface, they are driven down deep into the virgin ground, where the tubes start compressing the existing structure to the last limit. However, our team provide a diamerter from 200 to up to 300mm. The rig which is used during this process is a compressed 3-Ton rig with a width of 780mm.
This method is the same as a drop hammer, but the only difference is pneumatic air equipment, it produces less vibration in the ground as compared to the drop hammer method. You can have unlimited site access, with 100mm to 150 mm in diameter.
This method is used for semi-open and open sites for new buildings. However, the piling rig, which is used depends on pile specification, and it can range from 15 ton to 76 ton rigs.
So an auger string goes deep into the ground as one hit and depends on the piling rig specification. However, auger string can range from 12m down to 25m, with a particular Kelly bar, that push augers deep down. This is one of the quick methods, hardly takes 10-15 minutes for piling concrete, which pile diameter from 300mm to 600mm.
This method is workable, where a high load capacity of the pile is needed, where the piling depth is limited. A rotary piling rig can have a big diameter, so it allows us to get good ground bearing base like (circa 25cm).
RBA is the best option for chalk/clay ground, where we can form an open bore pile without concreting via an auger.
Rigs contain a telescopic bar and 1-1.5m auger at the rear end. An operator spins the auger into the ground at the same depth as an auger, removing auger out where the lifted soils rest at auger.