LCPC and GTR grain size classification

What Nourin reads in the sheet

• The retained and passing values from the grain size analysis sheet;
• The percentages passing the 0.08 mm, 2 mm, 50 mm and 80 mm sieves;
• The methylene blue value VBS and the plasticity index when available;
• The natural water content, the IPI and the consistency index;

What Nourin does with it

• Determines the LCPC class: gravel or sand, clean or clayey, well or poorly graded;
• Calculates the coefficients of uniformity C_u and curvature C_c by interpolation on the curve;
• Assigns the GTR class: A, B, C1/C2, D, R1 to R6 for rocks, F1 to F9 for special soils;
• Adds the moisture state (ts, s, m, h, th) and gives the full symbol, for example B21 m or A2 h;
• Indicates which parameters are missing to resolve an indeterminate case;

References