**Geotechnical drilling** is a fundamental part of any construction site evaluation. By drilling deep into the ground, engineers and architects gain insight into the conditions below, allowing them to account for environmental hazards. Here are some commonly used geotechnical drilling techniques:
- **Mud Rotary Drilling**: In this method, a rotating drill bit is used to cut through soil and rock. Water or drilling mud is pumped down the drill pipe to remove cuttings and stabilize the borehole. Mud rotary drilling is versatile and cost-effective for shallow, unconsolidated subsurface applications.
- **Hollow Stem Auger Drilling**: This technique uses force and torque applied to an aggressive drill bit and flighted augers (similar to a screw) to create a borehole. The flighted augers are hollow, providing stability while samples are taken or wells are installed. Hollow stem auger drilling is relatively inexpensive and well-suited for sands, silts, or clay environments.
- **Solid Stem Auger Drilling**: Similar to hollow stem auger drilling, solid stem auger drilling uses a non-hollow auger to advance into the subsurface. It's commonly used for soil sampling and well installation.
- **Sonic Drilling**: Sonic drilling resonates a series of connected steel drill pipes to advance into the subsurface. It's efficient and minimizes soil disturbance. Sonic drilling is suitable for various formations.
Each technique has its pros and cons, depending on the specific site conditions and project objectives . Remember that choosing the right method ensures accurate data collection during site investigations.