1200mm hydraulic casing extractor with Europe tier5 diesel engine power pack for secant pile foundation work

1200mm hydraulic casing extractor used for pull out 1200mm double wall casing during cased bored pile foundation work

1200mm hydraulic casing extractor with electricity motor power pack used for pull out od1200mm double wall casing during secant pile foundation work

1200mm hydraulic casing puller used for pull out double wall casing in cased bored pile foundation work

Casing extractor hydraulic type od1200mm used for pull out 1200mm double wall casing in secant pile foundation work

1180mm hydraulic casing extractor used for pull out od1180/1100mm double wall casing pile

1200mm Hydraulic Casing Extractor with 1000mm Reduction Insert Used for Pull out Od1200mm Double Wall Casing During Secant Pile Foundation Work

1000mm hydraulic casing extractor with 880mm reduction insert used for pull out od1000/id920mm double wall casing during secant pile foundation work
880mm hydraulic casing extractor used for pull out od880/id800mm double wall casing during secant pile foundation work
1500mm hydraulic casing extractor with 1200mm reduction insert used for pull out od1500/id1400mm double wall casing during secant pile foundation work
 1600mm hydraulic casing extractor  used for pull out od1600/id1520mm double wall casing during secant pile foundation work 1800mm hydraulic casing extractor  used for pull out od1800/id1700mm double wall casing during secant pile foundation work
2000mm hydraulic casing extractor  used for pull out od1800/id1700mm double wall casing during secant pile foundation work

1. B1200 CASING EXTRACTOR  DRAWING

1. Specification of diesel engine power pack

hydraulic casing extractor (often referred to as a casing jack or casing puller) is a specialized piece of heavy equipment used to retrieve temporary steel casings from the ground. While drilling rigs have their own pull-back force, they often lack the massive power required to overcome the skin friction of deep or large-diameter casings, especially in dense or "seizing" soils.

1. How It Works

The extractor acts as an auxiliary lifting unit. It consists of a heavy-duty frame, high-pressure hydraulic cylinders, and a clamping mechanism.

Clamping: The unit is positioned over the casing. Hydraulic jaws or a clamping ring "bite" onto the top of the steel casing.

Lifting (Jacking): Large hydraulic cylinders push against the ground (or a base plate) to lift the casing upward. This provides significantly more force (often hundreds of metric tons) than a standard crane or drilling rig.

Sequential Extraction: The casing is lifted in increments (strokes). Once the cylinders reach full extension, the clamp is released, the cylinders retract, and the process repeats until the friction is reduced enough for the drilling rig to take over.

2. Types of Extraction Equipment

Depending on the project requirements and the diameter of the casing, different configurations are used:

3. Key Technical Specifications

When evaluating a hydraulic extractor, the following parameters are critical:

Lifting Force: Usually measured in kilonewtons (kN) or tons. Common units range from 2,000 kN to over 10,000 kN (approx. 200 to 1,000 tons).

Stroke Length: The distance the cylinders can move in one cycle (typically 400mm to 1,000mm).

Clamping Force: The pressure applied to the casing to prevent slippage during the lift.

Maximum Diameter: The largest casing size the unit can accommodate (e.g., 2,000mm, 2,500mm, or 3,000mm).

4. When is an Extractor Necessary?

High Skin Friction: In stiff clays or dense sands where the surface area of the casing creates resistance beyond the rig's capacity.

Extended "Set" Time: If concrete pouring takes longer than expected, the casing can become "bound" to the surrounding soil as it settles.

Obstructions: If a casing becomes deformed or wedged against boulders or old foundations.

Deep Bored Piles: For piles exceeding 50–60 meters where the total weight and friction of the casing string are immense.

5. Operational Considerations

Base Stability: The ground around the borehole must be reinforced or use large spreader plates. Because the extractor pushes down on the soil to pull the casing up, poor ground stability can lead to the extractor sinking or the borehole collapsing.

Synchronization: It is vital to ensure the cylinders extend at the same rate to avoid tilting the casing, which can cause it to jam or damage the steel joints.

When is an casing Extractor Necessary?

hydraulic casing extractor becomes a technical necessity when the extraction force required to pull a temporary steel casing exceeds the safe operating limit of the piling rig’s winch or pull-back system.

In deep foundation work, the primary enemy is skin friction—the grip the surrounding soil has on the surface of the steel casing.

1. Soil Conditions (High Skin Friction)

The type of strata significantly impacts how easily a casing can be removed. An extractor is typically required in:

• Stiff Clays: These soils can create a "suction" effect and high adhesive friction against the steel.

• Dense Sands and Gravels: These materials can wedge themselves against the casing, creating immense lateral pressure.

• Artesian Conditions: Upward water pressure or shifting soil can increase the "grip" on the casing unexpectedly.

2. Rig Pulling Capacity Limits

Every drilling rig has a rated "pull-back" force. However, using 100% of a rig's capacity to pull a stuck casing puts extreme stress on the mast, hydraulic lines, and winches.

• Safety Margin: Engineers often bring in an extractor if the estimated friction is within 80% or more of the rig’s capacity to avoid mechanical failure or "tipping" risks.

• Mast Protection: Continual high-force pulling can lead to fatigue or misalignment of the rig's mast. An extractor transfers that force directly to the ground via its base plates, bypassing the rig entirely.

3. Large Diameter and Extreme Depth

As the diameter and depth of a pile increase, the surface area of the casing increases exponentially.

• Surface Area: A 2,000mm diameter casing has significantly more contact area with the soil than a 1,200mm casing.

• Deep Piles: Once casings exceed 40–50 meters, the combined weight of the steel and the total skin friction often necessitates auxiliary lifting power.

4. Time Delays and Concrete Curing

If there is a delay during the concrete pour (e.g., equipment breakdown or delivery issues), the concrete can begin to set or "bite" onto the casing.

• Concrete Bond: If the concrete reaches its initial set while the casing is still in the hole, the friction increases to a point where a standard rig cannot move it. The extractor's massive vertical force is required to break this bond.

5. Summary Table: Necessity Indicators

Factor

Threshold for Extractor Necessity

Extraction Force

Required force > 80% of Rig Pull-Back capacity.

Casing Diameter

Typically required for diameters > 1,500mm in dense soil.

Borehole Depth

Often necessary for depths exceeding 50 meters.

Time Delay

If extraction starts > 4 hours after the first concrete batch (depending on mix design).

Emergency

When the casing is "stuck" and the rig's winch is stalling.