Boring Log Soil Calculator

Step 1

Gradation

Enter percent passing by dry mass.

1-inch sieve % No. 4 sieve % No. 10 sieve % No. 40 sieve % No. 200 sieve %

Clean-soil gradation coefficients

D10, D30, and D60 are needed to distinguish well-graded from poorly graded clean sands and gravels.

D10 D30 D60

Step 2

Required when fines influence classification.

Water content % Liquid limit (LL) % Plasticity index (PI) %

Water content is reported with the result but does not determine the ASTM D2487 group symbol.

Water producing formation

Overrides the percentage-based moisture term and reports Water Bearing (WB).

Organic soil check

Oven-dried LL %

ASTM D2487 identifies an organic fine-grained soil when oven-dried LL / undried LL is less than 0.75.

Step 3

N is the sum of the second and third 6-inch increments.

First 6 in. Second 6 in. Third 6 in.

This reports the field N-value only. Energy, overburden, rod-length, and dilatancy corrections are outside this calculator.

Calculated result

The calculator will identify missing information rather than infer a classification that the data do not support.

USCS

AASHTO code—

AASHTO Group Index—

SPT N-value—

Field term—

Water content—

Moisture condition—

Cu—

Cc—

Description	Percent
No lesser constituents identified.

Decision-support tool only. Confirm the result against the current ASTM standard and qualified professional judgment.