Selection of Rotary Drilling Rigs' Drill Rods: Practical Selection Points for Friction Rods and Mechanical Lock Rods

    The drill rod of a rotary drilling rig directly determines the drilling efficiency, adaptability to the formation, and construction cost. The mainstream methods are friction drill rod and machine lock drill rod, which have significant differences in force transmission structure, applicable scenarios, and operational characteristics. Mastering the core differences can quickly and accurately select the appropriate type.

1、 Friction drill rod: preferred for efficient construction in soft formations

    Friction drill rods rely on the frictional force between the conical surfaces of the rods to transmit torque and drilling pressure. They have a simple structure and smooth expansion and contraction, and are commonly used in small and medium-sized drilling rigs.

Core advantages: Simple operation, flexible expansion and contraction, capable of achieving greater drilling depth, lighter weight, and low maintenance cost.

Applicable strata: low resistance strata such as clay, silt, sandy soil, backfill soil, fully weathered rock, etc.

Limitations: Limited pressure capacity, easy to slip when encountering hard rocks and dense formations, resulting in a significant decrease in drilling efficiency.

2、 Machine Lock Drill Rod: Specialized for Hard Rock and Complex Strata

    The machine lock drill rod is mechanically engaged through a locking point structure, forming a rigid connection without pressure loss, and can transmit full pressure and high torque.

Core advantages: Strong compression, strong torsional resistance, no slippage when drilling into hard rock and gravel layers, and stable pore quality.

Applicable strata: high-strength strata such as hard rock, moderately weathered/slightly weathered rock, dense pebble layer, and boulder layer, and can also be compatible with construction in soft strata.

Limitations: Large self weight, few sections, relatively limited drilling depth, precise locking and unlocking required for operation, higher maintenance requirements.

3、 Core principles of selection

    Determine the type based on the formation: soft formation, deep hole, and pursue efficient and low-cost selection of friction drill rods; Hard rock, complex formations, requiring strong pressure selection and locking of drilling rods.

Match parameters with drilling rig: select corresponding specifications of drill rods based on drilling rig tonnage, power head torque, design hole depth, and pile diameter.

Balancing construction costs: prioritizing friction rods in conventional geological formations to reduce investment; Geological complex projects, machine locking rods can reduce failures and improve project schedule guarantee.

In engineering construction, priority should be given to selecting based on the hardness of the formation and drilling resistance. If conditions permit, it can be used in combination, taking into account both universality and professionalism, and maximizing construction efficiency.