1200mm Spherical Grab Used with Casing Rotator for Bored Pile Foundation Work
详细信息
1200mm spherical grab used with casing rotator for bored pile foundation work1200mm spherical hammer grab used with casing rotator for bored pile foundation work
1200mm double rope spherical grab used with casing rotator for bored pile foundation work
Spherical grab is used on jobs where drilling has to be carried out free of vibrations and or where partially cased or uncased drilled shafts are to be produced, the high deadweight in conjunction with the high closing force ensures a high efficiency
Tianjin huachang xingye technology co ltd fabricate spherical grab operates through a double rope function. They have a strong grab force that is best for excavating hard soil and even soft rock
Double rope spherical grab with high close force suitable for vibration free boring in semi hard and hard soil conditions
Hammer grab with high clamping force, particularly suitable for drilling of holes in rocky soils and for working under water load
SPHERICAL GRAB for bored pile 800-3000mm
spherical Hammer grab is the most important tool used in piling and determines the progression of the drilling. In addition to the maximum grabbing capacity, unloading is quick and easy. The stresses of the whole structure are relieved and very strong
Surfaces exposed to wear are made of NM400 material. Chassis and arms that require strength are made material. Guides and holders are made of Q355 material.
We have two different spoon systems as below: Pulley Type X-Linked Type Spherical Type
| Casing size mm | L MM | L1 | B | B2 | weight |
| 2000/1880 | 4600 | 5700 | 1650 | 2200 | 17000 |
| 2500/2380 | 4600 | 6000 | 1750 | 2200 | 21000 |
| 2800/2680 | 4600 | 6200 | 1750 | 2200 | 23000 |
a casing rotator can absolutely be used in combination with a spherical grab (often referred to in the industry as a "round grab" or cuchara esférica). In fact, this pairing is a highly effective method for excavating large-diameter, deep boreholes in challenging ground conditions.
Here is a breakdown of how they work together, their specific use cases, and why this combination is chosen.
How the Combination Works
When constructing deep foundations (like bored piles or secant pile walls), a casing rotator is used to oscillate or fully rotate steel casings into the ground to keep the borehole from collapsing. As the casing sinks, the material inside the casing must be removed.
The Casing Rotator cuts through the ground, drives the heavy steel casing down, and handles the high-torque demands of breaking through tough strata or obstructions.
The Spherical Grab is dropped down inside the driven casing via a crane or drilling rig winch. The spherical shape perfectly matches the cylindrical interior of the casing, allowing it to efficiently scoop out the loose or broken material.
Optimal Use Cases
This specific equipment pairing excels in conditions where standard rotary drilling rigs with augers or buckets struggle:
Large Diameters and Extreme Depths: Spherical grabs are excellent for massive boreholes (often exceeding 1500mm to 3000mm in diameter) and deep excavations where a mechanical cable grab is more efficient than a rigid kelly bar. Tianjin huachang xingye technology co ltd
Cobbles, Boulders, and Boulders in Water: In alluvial soils filled with large river stones or boulders, standard drilling buckets can get stuck or fail to lift the rocks. A spherical grab can wrap its jaws around large boulders, while the casing rotator cuts through the surrounding matrix.
Underground Obstructions: If you are drilling through old concrete foundations, masonry, or timber piles, the casing rotator (equipped with a cutting shoe) crushes or shears the obstruction, and the spherical grab cleans out the heavy debris.
High Groundwater Tables: When drilling in unstable, water-bearing sands and gravels, keeping the casing advanced ahead of the excavation is critical to prevent boiling or piping at the base. The grab works effectively underwater inside the protective shell of the casing.
Advantages of Using a Spherical Grab inside a Rotator
| Feature | Advantage |
| Perfect Geometry | The rounded, spherical jaws maximize the volume of material grabbed per pass within a circular casing, reducing the number of cycles needed to clean the hole. |
| High Impact Force | Dropped mechanically, the heavy weight of the grab provides the necessary impact to penetrate dense gravels or packed soils inside the casing. |
| Reduced Casing Wear | Unlike rectangular grabs, a properly sized spherical grab minimizes the risk of damaging or gouging the inside walls of the steel casings during high-speed lowering and lifting. |
Clearance: It is critical that the maximum outer diameter of the opened spherical grab is properly matched to the inner diameter of the casing string (accounting for casing joint tolerances) to avoid jamming.
Cutting Shoe Coordination: The casing rotator relies on a hardened cutting shoe at the bottom of the lead casing. The grab should generally not excavate too far below the cutting shoe in unstable soils to prevent ground loss outside the casin
