What is a kelly bar and how many kinds of kelly bar are there?

What is a kelly bar? A Kelly bar is a specialized component used in the construction and drilling industry, primarily in the drilling of deep foundation piles or boreholes. It is an essential part of various types of drilling rigs, such as rotary drilling rigs, to facilitate the drilling process in challenging ground conditions.

There are several types and configurations of Kelly bars available, each designed for specific drilling applications and conditions. The choice of Kelly bar type depends on factors such as the drilling method, soil conditions, drilling rig design, and the depth of the foundation or borehole being drilled. Here are some common types of Kelly bars:

- Full Lock Kelly Bar:

Full lock Kelly bars have a solid structure with continuous outer and inner sections that are connected throughout their entire length. They provide maximum stability and are suitable for various drilling methods, including rotary drilling and continuous flight auger (CFA) drilling.

Applications: Suitable for a wide range of drilling methods, including rotary drilling, CFA (continuous flight auger) drilling, and drilling in various soil types.

Versatility: Provides maximum stability and torque transmission, making it suitable for most drilling applications.

- Friction Kelly Bar:

Friction Kelly bars are designed with an outer section that is smooth and an inner section with spiral grooves or keys. These bars rely on friction between the inner and outer sections to transmit torque. They are commonly used in rotary drilling and are versatile for various soil types.

Applications: Often used in rotary drilling methods, including bored pile drilling and diaphragm wall construction.

Soil Conditions: Effective in cohesive and non-cohesive soils where friction between the inner and outer sections of the Kelly bar can transmit torque.

- Interlocking Kelly Bar:

Interlocking Kelly bars consist of multiple sections that are connected using interlocking mechanisms. These bars are modular and can be extended or reduced in length as needed. They are suitable for deep foundation drilling and can handle varying drilling depths.

Applications: Suitable for deep foundation drilling where varying drilling depths are required.

Flexibility: Modular design allows for the extension or reduction of the Kelly bar's length to match the depth of the foundation or borehole.

- Telescopic Kelly Bar:

Telescopic Kelly bars are similar to interlocking Kelly bars but have telescoping sections that can extend or retract hydraulically. They are ideal for drilling boreholes to great depths, and their length can be adjusted as required.

Applications: Ideal for drilling very deep foundation piles or boreholes where the drilling depth needs to be adjusted frequently.

Hydraulic Control: The telescoping sections can be extended or retracted hydraulically, allowing for precise control over the drilling depth.

- Short Kelly Bar:

Short Kelly bars are designed for shallow drilling and are typically used when drilling relatively shallow foundation piles or when clearance height is limited. They are shorter in length compared to standard Kelly bars.

Applications: Used for shallow drilling where the depth of the foundation piles or boreholes is relatively limited.

Clearance Height: Suitable for situations with limited overhead clearance, such as under bridges or in confined spaces.

- Reinforced Kelly Bar:

Reinforced Kelly bars are designed to withstand heavy loads and challenging drilling conditions. They are often used in situations where high torque and axial forces are required, such as in hard rock drilling.

Applications: Used in challenging drilling conditions, including hard rock drilling and drilling in abrasive soils.

Heavy-Duty: Designed to withstand high torque and axial forces, making them suitable for demanding applications.

- Kelly Bar with Rock Auger:

Some Kelly bars are specially designed to work with rock augers, which are used for drilling in hard or rocky soil conditions. These bars are often reinforced to handle the increased load and wear associated with rock drilling.

Applications: Specifically designed for drilling in hard or rocky soil conditions where standard drilling tools may struggle.

Strength and Durability: Reinforced construction can handle the abrasion and impact associated with rock drilling.

- Soil Displacement Kelly Bar:

Soil displacement Kelly bars are used in displacement pile construction. They have a unique design that allows for the displacement of soil during drilling, creating a void that can be filled with concrete or another foundation material.

Applications: Used in displacement pile construction, where soil is displaced to create a void that can be filled with concrete or another foundation material.

Specialty Construction: Commonly used in secant pile walls, contiguous pile walls, and other situations where soil replacement is required.

DRILLMASTER ENGINEERING TECHNOLOGY CO., LTD. (DRILLMASTER) is a leading solution provider for foundation engineering. As the main enterprise entity, Drillmaster has three subsidiary companies: UNIMATE HEAVY INDUSTRY CO., LTD., P. A TECH CO., LTD., FOUNTECH ENGINEERING MACHINERY CO., LTD., respectively undertaking functions of fabrication, import, and R & D. Kelly bar is one of the main products for us.

Based on the stable quality and professional service, we have stable partner from over 50 countries and regions such as the U. S, the U. K, Singapore, Indonesia, Mexico, Russia, the Middle East and South America, etc.