Entering USCS Classification Data

Select Window > USCS to view the USCS classification window.

Note that many or all of the USCS data entry fields will be automatically filled in with data calculated by the program from your grain size and Atterberg limits tests. If you haven't entered these tests into the program yet, do so now:

Select Test > Enter GrainSize Data.
Enter your grain size distribution data.
Select Test > Enter LIMITS Data.
Enter your Atterberg limits test data.
Select Test > Enter Classifications Data.

The USCS Classification Window

Sieve percentages

Enter these values as numbers between 0 and 100.

The first field requires the percentage retained on the sieve, while the other sieve percentages reflect the percent passing each sieve.

Atterberg limits

Enter the liquid and plastic Atterberg limits for the soil.

The oven-dry liquid limit is used only for classifying possibly organic fine-grained soils (i.e, when 50 percent or more of the sample is fines). The oven-dry liquid limit field may be left blank when classifying coarse-grained soils, or fine-grained soils where the organic content is known to be minimal.

Diameters at X percent

These values, which represent the grain-size in millimeters at which 60, 30, and 10 percent of the sample is finer.

Diameters are required only when classifying coarse-grained soils.
If, after entering your grain size test data, the D10 value is blank, and a coarse-grained soil is being classified, select Test > Enter GrainSize Data then select Window > Chart. Next, add a shaping point on the right-side of the curve that extends the curve below the 10% scale line (this interpolates a D10 value), then return to your classification window (Test > Enter Classifications Data. (Again, since D10 is used only when classifying coarse-grained soils, this procedure is not required if 50% or more of the sample consists of fines.)

Borderline soil type

Second symbol

The software allows you to enter a second classification symbol if you think that the soil is on a borderline between two classifications (see ASTM D2487, Section 1.1). Doing so assigns the soil a dual classification such as "CL/CH" or "GM/SM": the first classification is the one selected by the program, and the classification after the slash is the one you choose.

If you want to assign a dual classification to the soil, click on the Borderline soil type check box, then enter the soil's second classification into the Second symbol box. (Note that the slash "/" is automatically added so you do not need to enter it as part of the second classification.)

The Borderline soil type check box will be disabled if the program classifies your soil using a dual symbol such as GP-GM or CL-ML.

Add the group name to your soil description

Insert Group Name at the Cursor

The box underneath Add the group name to your soil description lists your current soil description: if you'd like to insert the classification group symbol into the description, click inside the box, move the editing cursor to the position where the group symbol is to be located, then click on the Insert Group Name at the Cursor button.