Segmentally cased holes are the safest and most reliable method in the deep drilling through caving or slaking ground conditions above or below the ground water table.  
The segmental casing that can be drive with the rotary drill rig, the oscillator, or the casing rotator. The diameters of the casings range from 500mm to 3500mm.
The structure of the segmental casing could be single walled, double walled or simplified. Thesingle walled casingis made of one male joint, one female joint and one layer of steel pipe. Thedouble walled casingis made of one male joint, one female joint, two layers of steel pipes and reinforce bar. Both of them are temperately placed in and will draw out during concreting. The simplified casing does not have joints and used as permanently casing mostly.
The segmental casings are widely used in the bridge foundation works, metro construction, cast-in-suit piles and so on.

The steps of the segmentally cased holes:

A.Drilling the hole with the bucket, auger or core barrel;
B.Driving the segmental casing in to the hole by a rotary drilling rig (need casing adaptor as connection with rotary head), or a casing oscillator or a casing rotator;
C.Installing the reinforcement cage in to the hole;
D.Pouring the concrete into the cased borehole through tremie pipe and hopper;
E.Drawing out the segmental casing during the concreting;
F.Moving to the next borehole.
The spare parts of the segmental casing by rotary drilling rig would need the casing tools such as double wall casing tube or single wall casing tube, casing shoe, casing adaptor and casing connector, and also extracasing joint, casing screws and casing teeth as spare parts.
Wearing parts: Casing bolt, casing thread and casing nut, quick change casing teeth and holder

Matched with piling rigs: Bauer, Soilmec, Casagrande, IMT, MAIT, CMV, SANY, ZOOMLION, Jintai, XCMG