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Sitework & Earthworkaka: boringaka: geotechnical boringaka: test boringaka: B-hole

Soil Boring

In Plain English

Drilling a hole in the ground to collect soil samples and determine what's underground before designing foundations.

Definition

A subsurface investigation technique where a drill rig advances a borehole into the ground to retrieve soil samples and perform in-situ tests at various depths. Soil borings are performed by geotechnical engineers to determine soil stratification, bearing capacity, groundwater conditions, and other properties needed for foundation design. The data is summarized in a geotechnical report with boring logs.

Why It Matters in Bidding

Soil borings drive foundation design, which is one of the largest cost and risk variables on any project. If a geotechnical report is available at bid time, the estimator can scope excavation, dewatering, over-excavation, and deep foundations accurately; if borings are missing or limited, that uncertainty must be carried as a qualification or contingency rather than absorbed silently.

Example

Before submitting a bid on a warehouse, the estimator reviews the boring logs in the geotechnical report, sees the water table sits two feet above footing elevation, and adds a dewatering and pumping line item the other bidders may have overlooked.

Related Terms

Soil Compaction TestSubgradeUnderpinningExcavation

Frequently Asked Questions

On most projects the owner commissions and pays for the geotechnical investigation during design, then shares the report with bidders. If borings are not provided, contractors should not assume favorable conditions; instead they qualify the bid based on available data and may price the investigation as an added scope if required.
Boring logs reveal bearing capacity, soil layers, and groundwater, which determine whether you can use shallow spread footings or need piles, piers, or ground improvement. They also flag unsuitable soils requiring removal and replacement. Without this data, foundation pricing is a guess, so estimators rely on the logs to scope excavation and structural support.
Submit your bid with a written qualification stating it is based on assumed soil conditions and excludes unforeseen subsurface issues, rock, or groundwater. Carry a contingency where allowed, and request the report or borings during the RFI period so unknown conditions become a change-order item rather than your loss.

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