Geotechnical Investigations AHA (Activity Hazard Analysis / Job Hazard Analysis)
Updated 2026-06-23
A Geotechnical Investigations AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew performing geotechnical investigations safe from the drilling and boring equipment, from utility strikes and ground penetration, and in the test-pit excavation and terrain. Geotechnical investigations explore and test the subsurface soil and rock for engineering design — combining the drilling and boring-equipment/rotating-and- struck-by hazard, the utility-strike and ground-penetration hazard, and the test-pit-excavation and terrain hazard. This guide walks through building a Geotechnical Investigations AHA that names the drilling/boring- equipment, utility-strike/ground-penetration, and test-pit-excavation/terrain hazards and assigns the drilling, utility, and excavation controls that hold up in the field.
Why geotechnical investigations needs its own AHA
Geotechnical investigations explore and characterize the subsurface soil and rock conditions for engineering design and construction — through soil borings, drilling and sampling (SPT, split-spoon, undisturbed sampling), test pits, cone penetration testing (CPT), and in-situ testing — to determine soil properties, rock, groundwater, and bearing conditions. The defining features are the drilling and boring (rotating equipment, rig), the ground penetration (utility-strike hazard), and the test-pit excavation. The hazards combine the drilling and boring- equipment/rotating-and-struck-by (drilling and boring use a drill rig with a rotating drill string/auger — the caught-in/entanglement hazard of the rotating drill string, the struck-by hazards (rig, mast, tooling), and the mast/overhead), the utility-strike and ground-penetration (borings, drilling, CPT, and test pits penetrate the ground — the utility-strike hazard (penetrating buried utilities is serious/fatal), requiring utility locating and boring clearance), the test-pit-excavation and terrain (test pits are excavations — the excavation hazards (cave-in, entry), and the site terrain), and the sample/environmental. The drilling/boring-equipment and the utility-strike/ground-penetration justify a dedicated AHA.
Breaking geotechnical investigations into steps
The steps for a Geotechnical Investigations AHA follow the investigation:
- Plan the investigation and locate utilities (critical)
- Clear the boring/test-pit locations of utilities
- Drill and bore (rotating equipment, mast)
- Sample and test the subsurface
- Excavate the test pits (cave-in protection)
- Manage the drilling, utility, and excavation hazards
- Backfill/secure the borings and pits
- Document the geotechnical data
Each step carries a hazard, and the drilling/boring-equipment, the utility-strike/ground-penetration, and the test-pit-excavation/terrain are where the most significant risks concentrate.
The hazards step by step
Drilling and boring-equipment/rotating-and-struck-by
Drilling and boring use a drill rig with a rotating drill string/auger — the caught-in/entanglement hazard of the rotating drill string, the struck-by hazards (rig, mast, tooling), and the mast/overhead. The controls are keeping clear of the rotating drill string/auger (a major caught-in hazard — no loose clothing, stay clear), struck-by awareness around the rig and tooling, overhead-clearance checks for the mast (near power lines), qualified drill-rig operation, and the drilling controls. The drilling/boring-equipment is a defining hazard — the rotating drill string is a serious caught-in hazard. (These follow the drilling-equipment fundamentals.)
Utility-strike and ground-penetration
Borings, drilling, CPT, and test pits penetrate the ground — the utility-strike hazard (penetrating buried utilities is serious/fatal), requiring utility locating and boring clearance. The controls are utility locating and clearing each boring/test-pit location before penetrating (the critical control — hand-clearing/vacuum- excavating the top of each boring), awareness of underground hazards, and the utility/penetration controls. The utility-strike/ground-penetration is a defining hazard — penetrating a utility is serious, so locating/clearing is critical. (These follow the ground-disturbance fundamentals.)
Test-pit-excavation and terrain
Test pits are excavations — the excavation hazards (cave-in, entry), and the site terrain. The controls are excavation safety for the test pits (cave-in protection, not entering unprotected excavations, competent-person inspection), careful movement on the site terrain, and the excavation/terrain controls. The test-pit-excavation/ terrain is a defining hazard — test pits are excavations with cave-in hazards. (These follow the excavation-safety fundamentals.)
Sample/environmental
The sample handling and environmental (samples, weather, biological) carries the sample/environmental hazard. The controls are safe sample handling, weather/biological protection, and the sample/environmental controls. (These follow the sample-handling fundamentals.)
A simple Geotechnical Investigations AHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Plan / locate | Utility strike | Plan investigation, locate utilities (critical) | project |
| Clear locations | Utility strike | Clear boring/test-pit locations (hand-clear top) | project |
| Drill/bore | Caught-in / rotating | Keep clear of rotating drill string, mast clearance | OSHA 1926.1408 |
| Sample/test | Subsurface | Sample and test the subsurface | project |
| Excavate test pits | Cave-in | Excavation safety, cave-in protection, no unprotected entry | OSHA 1926.652 |
| Backfill/secure | Open hole | Backfill/secure the borings and pits | project |
Utility clearing and drilling/excavation safety
A Geotechnical Investigations AHA centers on utility clearing and drilling/excavation safety. The utility clearing addresses the ground penetration — controlled by utility locating and clearing each boring and test-pit location before penetrating (hand-clearing or vacuum-excavating the top of each), since penetrating a utility is serious or fatal. The drilling/excavation safety addresses the drill rig and test pits — controlled by keeping clear of the rotating drill string (a major caught-in hazard), struck-by awareness, overhead-clearance checks for the mast, and excavation safety for the test pits (cave-in protection, no unprotected entry). And the samples get handling controls. An AHA built on utility clearing and drilling/excavation safety, with sample controls, addresses the hazards that define geotechnical investigations.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, geotechnical investigations explore the subsurface for engineering design, and they combine the hazards of the previous subsurface-investigation doc (drilling and utility strikes) with the added hazard of test-pit excavations. The utility-strike and ground- penetration hazard is a primary defining concern — borings, drilling, cone penetration testing, and test pits all penetrate the ground, and penetrating a buried utility is serious or fatal (drilling or excavating into an electrical line electrocutes, into a gas line can explode), so utility locating and clearing each boring and test-pit location before penetrating is the critical control, including hand-clearing or vacuum-excavating the top few feet of each boring to physically confirm it is clear before the rig or excavator penetrates. This is the same discipline as subsurface investigation: never penetrate unlocated, uncleared ground.
The drilling/boring-equipment and the test-pit-excavation/terrain are the other defining hazards. On the projects I have run, geotechnical drilling uses a drill rig with a rotating drill string or auger, and the rotating drill string is a major caught-in and entanglement hazard (it can catch loose clothing, gloves, or a person), so keeping clear of the rotating drill string, struck-by awareness around the rig and tooling, overhead-clearance checks for the mast near power lines, and qualified drill-rig operation are the controls. And the distinctive addition in geotechnical work is the test pit: test pits are excavations dug to observe and sample the subsurface directly, and they carry the full excavation hazards — cave-in being the deadly one — so excavation safety for the test pits (cave-in protection, not entering unprotected excavations, and competent-person inspection) is a real concern. A test pit is an excavation, and people are sometimes tempted to enter a "small" test pit to observe or sample without protection, which is exactly the cave-in fatality scenario, so the excavation discipline applies fully. The sample handling and environmental hazards round it out. The AHA built on utility clearing and drilling/excavation safety is the one that protects the geotechnical-investigation crew.
The bottom line
A Geotechnical Investigations AHA names the drilling/boring-equipment, the utility-strike/ground-penetration, and the test-pit-excavation/terrain hazards with specific controls — locating and clearing each boring and test pit before penetrating (penetrating a utility is serious/fatal), keeping clear of the rotating drill string with mast clearance, and full excavation safety for the test pits (cave-in protection, no unprotected entry). The utility clearing and the drilling/excavation safety are the defining concerns. The AHA that manages both is the one that protects the crew.
Frequently asked questions
Why is clearing each boring and test-pit location critical?
Borings, drilling, CPT, and test pits all penetrate the ground, and penetrating a buried utility is serious or fatal (drilling or excavating into an electrical line electrocutes, into a gas line can explode). Controls are utility locating and clearing each boring/test-pit location before penetrating (hand-clearing or vacuum-excavating the top few feet to physically confirm it is clear before the rig or excavator penetrates), awareness of underground hazards, and the utility/penetration controls.
Why is the rotating drill string a serious hazard?
Geotechnical drilling uses a drill rig with a rotating drill string or auger, and the rotating drill string is a major caught-in and entanglement hazard (it can catch loose clothing, gloves, or a person). Controls are keeping clear of the rotating drill string/auger (no loose clothing, stay clear), struck-by awareness around the rig and tooling, overhead-clearance checks for the mast (near power lines), qualified drill-rig operation, and the drilling controls.
Why do test pits carry excavation hazards?
Test pits are excavations dug to observe and sample the subsurface directly, so they carry the full excavation hazards — cave-in being the deadly one — and people are sometimes tempted to enter a "small" test pit to observe or sample without protection, which is exactly the cave-in fatality scenario. Controls are excavation safety for the test pits (cave-in protection, not entering unprotected excavations, competent-person inspection), careful movement on the site terrain, and the excavation/terrain controls.
What are geotechnical investigations?
Geotechnical investigations explore and characterize the subsurface soil and rock conditions for engineering design and construction — through soil borings, drilling and sampling, test pits, cone penetration testing, and in-situ testing — to determine soil properties, rock, groundwater, and bearing conditions. Because they involve drilling (rotating/struck-by), ground penetration (utility strike), and test-pit excavations (cave-in), those hazards apply.
Related AHAs and JHAs
- Subsurface Drilling and Sampling AHA — the drilling and sampling detail
- Exploratory Excavations AHA — the test-pit and exploratory excavation
- Excavation and Trenching JHA — the excavation fundamentals for test pits
- Core Drilling and Concrete Saw Cutting JHA — related drilling fundamentals
Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.