Key Considerations for Rotary Drilling Rigs Operating in Granite Soil Layers English Content:

Granite soil layers are challenging for foundation engineering due to their high hardness, dense structure, and strong compressive strength. Rotary drilling rigs working under these complex geological conditions require not only high-performance tools and equipment but also scientific operational methods and construction strategies. Here are the key considerations for operating rotary drilling rigs in granite soil layers:

1. Selecting the Right Drilling Tools

1. High-Strength Tools
   Granite soil layers demand drilling tools with high strength and wear resistance. Use tools made of hard alloys or high-strength steel, such as rock augers, alloy drill bits, or core barrels.

2. Impact-Assisted Tools
   For extremely dense granite layers, consider using tools with impact functions or adding impact devices to enhance the efficiency of rock breaking.

2. Optimizing Equipment Parameters

1. Adjusting Drilling Pressure
   In granite soil layers, increase drilling pressure appropriately to improve rock-breaking capability. However, avoid excessive pressure to prevent equipment overload or damage to the drill rod.

2. Reducing Rotation Speed
   Lowering the drill bit’s rotation speed reduces equipment wear and improves the drill bit’s grip on the rock, enhancing drilling efficiency.

3. Using Mud Appropriately
   Ensure proper mud flow and pressure during drilling to cool the drill bit, reduce friction, and effectively remove debris.

3. Construction Techniques

1. Segmental Drilling
   Granite soil layers are hard, so adopt segmental drilling. Start with shallow drilling and gradually deepen to reduce the load on the equipment.

2. Regular Borehole Cleaning
   Hard rock generates significant debris that can clog boreholes. Regular cleaning maintains drilling efficiency and stabilizes borehole walls.

3. Monitoring Equipment Status
   Continuously monitor parameters such as vibration, rotation speed, and drilling pressure during operations. Stop immediately if abnormalities are detected to prevent equipment damage from prolonged overload.

4. Strengthening Equipment Maintenance

1. Routine Inspection and Maintenance
   After construction, thoroughly inspect critical components of the rig and replace heavily worn parts, particularly the drill bit and gear components.

2. Lubrication and Protection
   Granite soil layers cause significant wear on equipment. Strengthen lubrication to prevent early damage to metal parts due to high-intensity operations.

3. Hydraulic System Maintenance
   The hydraulic system is the core of the rotary drilling rig. Regularly check for leaks or insufficient pressure to ensure efficient operation.

5. Safety Precautions

1. Geological Survey and Planning
   Before construction, fully understand the thickness and characteristics of the granite layer. Develop a detailed construction plan to minimize unexpected impacts.

2. Preventing Stuck Drill Rods
   Granite layers can easily cause stuck drill rods. Control speed and pressure during drilling and clean the borehole promptly to reduce resistance.

3. Operating Standards and Emergency Plans
   Operators must follow standard procedures and have pre-established emergency plans for issues such as stuck or broken drill rods.

Conclusion

Operating rotary drilling rigs in granite soil layers requires thorough preparation, proper tool selection, optimized construction parameters, and enhanced equipment maintenance. Additionally, scientific strategies and robust safety management are essential to improving efficiency and ensuring project success. By adhering to these considerations, equipment wear can be minimized, construction efficiency improved, and project quality ensured.