I. Operational Best Practices

1. Precision Path Planning

• Utilize RTK-GPS systems for real-time trajectory monitoring, ensuring alignment accuracy within ±30 cm. Pre-construction surveys must identify underground utilities to avoid collisions.

2. Dynamic Parameter Adjustment

• Soft Soil Layers (N-value <10): Maintain thrust ≤80 kN and rotation speed 15-20 RPM

• Sandy Gravel Layers (N-value 15-25): Increase thrust to 120 kN, reduce speed to 8-12 RPM

• Hard Rock Formations (Compressive strength >30 MPa): Deploy roller-bit reamers with torque ≥25,000 N·m

3. Mud System Optimization

• Base mud composition: 5-7% bentonite + 0.5-1.0% lubricant + 0.3-0.5% anti-collapse agent

• Flow rate control: 0.8-1.2 m³/min during pilot hole drilling, escalating to 1.5-2.0 m³/min for reaming

II. Comprehensive Maintenance Framework

1. Hydraulic System Care

• Fluid replacement: Replace HM46 anti-wear hydraulic oil every 2,000 hours, coupled with filter element cleaning

• Pressure calibration: Monitor pressure fluctuations (>15% deviation requires pump inspection)

2. Critical Component Servicing

• Drill Pipes: Inspect wall thickness loss (≤15% allowable) every 500 hours; apply thread lubricant to coupling areas

• Reamers: Post-rock-layer operations mandate high-pressure flushing of blade gaps, bearing clearance checks (0.05-0.1 mm tolerance)

3. Cooling System Management

• Daily radiator cleaning to maintain >70% airflow efficiency

• High-temperature environments (>35℃) require auxiliary cooling modules to stabilize oil temperature ≤65℃

III. Specialized Scenario Solutions

1. River Crossings

• Implement dual-wall drill pipes with closed-loop mud systems to prevent contamination

• Install pressure sensors on drill heads (safe differential pressure <1.5 MPa)

2. Hard Rock Penetration

• Progressive reaming: Φ600→Φ900→Φ1200 mm incremental enlargement

• Speed restriction: <1 m/h with 50 cm interval wear inspections

Conclusion: HDD operations require integrating precision engineering with proactive maintenance. By adopting digital monitoring systems that track vibration spectra and oil particulate levels, predictive maintenance can reduce downtime by 40% and extend major overhaul intervals beyond 8,000 hours. Continuous technological adoption ensures sustainable infrastructure development while minimizing ecological footprints.