The telescopic drilling technique, which is part of the present invention, is an advanced approach for drilling deep, wide, and stable foundation bores.
Unlike prior art drilling methods, which require multiple casing replacements and frequent extraction of components, the telescopic method relies on a progressive system of conduits that extend the bore without interrupting the drilling process.
his minimizes vibration stress, unnecessary delays, and risks such as bore collapsing during deeper phases of the shaft.
A key principle is that the hollow outer conduit establishes the initial diameter, followed by a first hollow inner conduit and a rotatable inner drill bit that advances the hole with structural accuracy.
Each drill rod segment inserted enables a successive outer bore depth, helping maintain a smooth flow even in mixed soil types or unpredictable rock layers.
Because the outer bore wall remains supported at each stage, including the next casing segment the method significantly enhances operational safety while maintaining precision.
When to use telescopic drilling in construction?
Telescopic drilling becomes essential when foundation loads are high or when engineers must form in situ concrete piles with strict geometric tolerances.
Deep structures, such as energy infrastructure, bridge footings, and commercial tower bases, typically require a method capable of sustaining vertical alignment even across water layer transitions or areas where granular soil shifts under pressure.
This is also useful for environments where drilling operation creates stress on surrounding ground elements. By controlling vibration and stabilizing the bore’s outer conduit engaging the formation, the technique avoids creating cracks, settlement, or deformation in nearby structures.
Ideal for secant pile walls and retaining structures
Secant pile walls demand precision to avoid breached prior segments. With the telescopic method, the outer bore is consistently maintained along the full casing length, reducing the risk of overlap errors.
The system is strong enough to handle changes in outer walls density and ensures the final secant alignment remains within engineering tolerances.
Effective for mixed layers and challenging environments
When present drilling methods struggle with layered soil, including clay, gravel, fractured rock, or water intrusion, the telescopic drilling method provides stability and reduced material expenditures.
Its ability to adapt to different resistances makes it ideal for projects where the initial depth rapidly transitions into more demanding rock layer formations.
Benefits of telescopic drilling method over traditional methods
The telescopic method includes several performance benefits, particularly when the drilling process recommenced after interruptions.
- Extended depth control, reaching twenty five feet or more without removing conduits.
- Reduced vibration stress, minimizing structural strain on both machinery and the ground.
- Better torque delivery, especially when paired with a telescopic Kelly bar to enhance crowd force and rotary drive efficiency.
- Higher efficiency in large-diameter applications, reducing time and material expenditures compared to prior art drills.
- Improved alignment thanks to stable outer bore base support.
Drilling Equipment required for telescopic drilling method
A successful telescopic drilling setup depends on coordinated drilling equipment, properly engineered casing structures, and stable torque transmission components. Because long conduits and special machinery are often required, compatibility with the rotary drive system is crucial.
Hollow outer conduit
The hollow outer conduit defines the outer bore, stabilizes the outer bore base, and prevents the upper section from collapsing during deeper penetration. It also aligns the casing segment with the next drill rod segment.
First inner conduit & second inner conduit
The first inner conduit drives the unitary drill bit head and the ring bit, setting the path for subsequent drilling. The second inner conduit, sometimes called the preceding inner conduit, expands the bore to a successive depth, maintaining the bore’s cylindrical geometry.
Ring drill & ring drill bit systems
A ring drill and ring drill bit, often of five eighths inch diameter, create clean cuts when drilling through stratified materials. Their ability to move longitudinally through the outer bore defined structure helps preserve bore shape and reduces risks of misalignment.
Telescopic Kelly bar integration
The telescopic Kelly bar increases torque stability and ensures that the drill end remains effective in supporting deeper drilling operations. It is especially valuable in terrains where soil types vary or where the formation causes uneven resistance.
Special machinery and rotary drive compatibility
Modern rigs built for telescopic drilling, like those manufactured by Everstar Machinery, enhance torque consistency, casing accuracy, and safety. They also help prevent human injury by reducing reliance on manual retrieval of conduits.
Conclusion
The telescopic drilling technique delivers reliable deep-foundation performance by strengthening bore stability, reducing vibration stress, and minimizing time and material expenditures.
Its staged conduit approach adapts to layered formations, water obstacles, and demanding construction needs more efficiently than prior art drills.
Everstar offers advanced telescopic drilling tools, telescopic Kelly bars, and high-performance drilling machinery engineered for stability and precision.
For equipment selection or project planning support, including such transport logistics our technical specialists are ready to assist with every drilling operation.
